Installing a cluster on bare metal with network customizations

In OKD version 4.6, you can install a cluster on bare metal infrastructure that you provision with customized network configuration options. By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing MTU and VXLAN configurations.

You must set most of the network configuration parameters during installation, and you can modify only kubeProxy configuration parameters in a running cluster.

Prerequisites

Machine requirements for a cluster with user-provisioned infrastructure

For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.

Required machines

The smallest OKD clusters require the following hosts:

  • One temporary bootstrap machine

  • Three control plane, or master, machines

  • At least two compute machines, which are also known as worker machines. If you are running a three-node cluster, running zero compute machines is supported. Running one compute machine is not supported.

The cluster requires the bootstrap machine to deploy the OKD cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster.

To maintain high availability of your cluster, use separate physical hosts for these cluster machines.

The bootstrap and control plane machines must use Fedora CoreOS (FCOS) as the operating system. However, the compute machines can choose between Fedora CoreOS (FCOS) or Fedora 7.9.

See Red Hat Enterprise Linux technology capabilities and limits.

Network connectivity requirements

All the Fedora CoreOS (FCOS) machines require network in initramfs during boot to fetch Ignition config files from the Machine Config Server. During the initial boot, the machines require either a DHCP server or that static IP addresses be set in order to establish a network connection to download their Ignition config files. Additionally, each OKD node in the cluster must have access to a Network Time Protocol (NTP) server. If a DHCP server provides NTP servers information, the chrony time service on the Fedora CoreOS (FCOS) machines read the information and can sync the clock with the NTP servers.

Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

MachineOperating SystemvCPU [1]Virtual RAMStorageIOPS [2]

Bootstrap

FCOS

4

16 GB

100 GB

300

Control plane

FCOS

4

16 GB

100 GB

300

Compute

FCOS

2

8 GB

100 GB

300

  1. One vCPU is equivalent to one physical core when simultaneous multithreading (SMT), or hyperthreading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = vCPUs.

  2. OKD and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.

Certificate signing requests management

Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager only approves the kubelet client CSRs. The machine-approver cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.

Creating the user-provisioned infrastructure

Before you deploy an OKD cluster that uses user-provisioned infrastructure, you must create the underlying infrastructure.

Prerequisites

Procedure

  1. Configure DHCP or set static IP addresses on each node.

  2. Provision the required load balancers.

  3. Configure the ports for your machines.

  4. Configure DNS.

  5. Ensure network connectivity.

Networking requirements for user-provisioned infrastructure

All the Fedora CoreOS (FCOS) machines require network in initramfs during boot to fetch Ignition config from the machine config server.

During the initial boot, the machines require either a DHCP server or that static IP addresses be set on each host in the cluster in order to establish a network connection, which allows them to download their Ignition config files.

It is recommended to use the DHCP server to manage the machines for the cluster long-term. Ensure that the DHCP server is configured to provide persistent IP addresses and host names to the cluster machines.

The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.

You must configure the network connectivity between machines to allow cluster components to communicate. Each machine must be able to resolve the host names of all other machines in the cluster.

Table 1. All machines to all machines
ProtocolPortDescription

ICMP

N/A

Network reachability tests

TCP

1936

Metrics

9000-9999

Host level services, including the node exporter on ports 9100-9101 and the Cluster Version Operator on port 9099.

10250-10259

The default ports that Kubernetes reserves

10256

openshift-sdn

UDP

4789

VXLAN and Geneve

6081

VXLAN and Geneve

9000-9999

Host level services, including the node exporter on ports 9100-9101.

TCP/UDP

30000-32767

Kubernetes node port

Table 2. All machines to control plane
ProtocolPortDescription

TCP

6443

Kubernetes API

Table 3. Control plane machines to control plane machines
ProtocolPortDescription

TCP

2379-2380

etcd server and peer ports

Network topology requirements

The infrastructure that you provision for your cluster must meet the following network topology requirements.

OKD requires all nodes to have internet access to pull images for platform containers and provide telemetry data to Red Hat.

Load balancers

Before you install OKD, you must provision two load balancers that meet the following requirements:

  1. API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:

    • Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the API routes.

    • A stateless load balancing algorithm. The options vary based on the load balancer implementation.

    Do not configure session persistence for an API load balancer.

    Configure the following ports on both the front and back of the load balancers:

    Table 4. API load balancer
    PortBack-end machines (pool members)InternalExternalDescription

    6443

    Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the /readyz endpoint for the API server health check probe.

    X

    X

    Kubernetes API server

    22623

    Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.

    X

    Machine config server

    The load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the /readyz endpoint to the removal of the API server instance from the pool. Within the time frame after /readyz returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.

  2. Application Ingress load balancer: Provides an Ingress point for application traffic flowing in from outside the cluster. Configure the following conditions:

    • Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the Ingress routes.

    • A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.

    Configure the following ports on both the front and back of the load balancers:

    Table 5. Application Ingress load balancer
    PortBack-end machines (pool members)InternalExternalDescription

    443

    The machines that run the Ingress router pods, compute, or worker, by default.

    X

    X

    HTTPS traffic

    80

    The machines that run the Ingress router pods, compute, or worker, by default.

    X

    X

    HTTP traffic

If the true IP address of the client can be seen by the load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.

A working configuration for the Ingress router is required for an OKD cluster. You must configure the Ingress router after the control plane initializes.

NTP configuration

OKD clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.

If a DHCP server provides NTP server information, the chrony time service on the Fedora CoreOS (FCOS) machines read the information and can sync the clock with the NTP servers.

Additional resources

User-provisioned DNS requirements

DNS is used for name resolution and reverse name resolution. DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Fedora CoreOS (FCOS) uses the reverse records to set the host name for all the nodes. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OKD needs to operate.

The following DNS records are required for an OKD cluster that uses user-provisioned infrastructure. In each record, <cluster_name> is the cluster name and <base_domain> is the cluster base domain that you specify in the install-config.yaml file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>..

Table 6. Required DNS records
ComponentRecordDescription

Kubernetes API

api.<cluster_name>.<base_domain>.

Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

api-int.<cluster_name>.<base_domain>.

Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. These records must be resolvable from all the nodes within the cluster.

The API server must be able to resolve the worker nodes by the host names that are recorded in Kubernetes. If the API server cannot resolve the node names, then proxied API calls can fail, and you cannot retrieve logs from pods.

Routes

*.apps.<cluster_name>.<base_domain>.

Add a wildcard DNS A/AAAA or CNAME record that refers to the load balancer that targets the machines that run the Ingress router pods, which are the worker nodes by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

Bootstrap

bootstrap.<cluster_name>.<base_domain>.

Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the bootstrap machine. These records must be resolvable by the nodes within the cluster.

Master hosts

<master><n>.<cluster_name>.<base_domain>.

DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes (also known as the master nodes). These records must be resolvable by the nodes within the cluster.

Worker hosts

<worker><n>.<cluster_name>.<base_domain>.

Add DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the worker nodes. These records must be resolvable by the nodes within the cluster.

You can use the nslookup <hostname> command to verify name resolution. You can use the dig -x <ip_address> command to verify reverse name resolution for the PTR records.

The following example of a BIND zone file shows sample A records for name resolution. The purpose of the example is to show the records that are needed. The example is not meant to provide advice for choosing one name resolution service over another.

Sample DNS zone database

  1. $TTL 1W
  2. @ IN SOA ns1.example.com. root (
  3. 2019070700 ; serial
  4. 3H ; refresh (3 hours)
  5. 30M ; retry (30 minutes)
  6. 2W ; expiry (2 weeks)
  7. 1W ) ; minimum (1 week)
  8. IN NS ns1.example.com.
  9. IN MX 10 smtp.example.com.
  10. ;
  11. ;
  12. ns1 IN A 192.168.1.5
  13. smtp IN A 192.168.1.5
  14. ;
  15. helper IN A 192.168.1.5
  16. helper.ocp4 IN A 192.168.1.5
  17. ;
  18. ; The api identifies the IP of your load balancer.
  19. api.ocp4 IN A 192.168.1.5
  20. api-int.ocp4 IN A 192.168.1.5
  21. ;
  22. ; The wildcard also identifies the load balancer.
  23. *.apps.ocp4 IN A 192.168.1.5
  24. ;
  25. ; Create an entry for the bootstrap host.
  26. bootstrap.ocp4 IN A 192.168.1.96
  27. ;
  28. ; Create entries for the master hosts.
  29. master0.ocp4 IN A 192.168.1.97
  30. master1.ocp4 IN A 192.168.1.98
  31. master2.ocp4 IN A 192.168.1.99
  32. ;
  33. ; Create entries for the worker hosts.
  34. worker0.ocp4 IN A 192.168.1.11
  35. worker1.ocp4 IN A 192.168.1.7
  36. ;
  37. ;EOF

The following example BIND zone file shows sample PTR records for reverse name resolution.

Sample DNS zone database for reverse records

  1. $TTL 1W
  2. @ IN SOA ns1.example.com. root (
  3. 2019070700 ; serial
  4. 3H ; refresh (3 hours)
  5. 30M ; retry (30 minutes)
  6. 2W ; expiry (2 weeks)
  7. 1W ) ; minimum (1 week)
  8. IN NS ns1.example.com.
  9. ;
  10. ; The syntax is "last octet" and the host must have an FQDN
  11. ; with a trailing dot.
  12. 97 IN PTR master0.ocp4.example.com.
  13. 98 IN PTR master1.ocp4.example.com.
  14. 99 IN PTR master2.ocp4.example.com.
  15. ;
  16. 96 IN PTR bootstrap.ocp4.example.com.
  17. ;
  18. 5 IN PTR api.ocp4.example.com.
  19. 5 IN PTR api-int.ocp4.example.com.
  20. ;
  21. 11 IN PTR worker0.ocp4.example.com.
  22. 7 IN PTR worker1.ocp4.example.com.
  23. ;
  24. ;EOF

Generating an SSH private key and adding it to the agent

If you want to perform installation debugging or disaster recovery on your cluster, you must provide an SSH key to both your ssh-agent and the installation program. You can use this key to access the bootstrap machine in a public cluster to troubleshoot installation issues.

In a production environment, you require disaster recovery and debugging.

You can use this key to SSH into the master nodes as the user core. When you deploy the cluster, the key is added to the core user’s ~/.ssh/authorized_keys list.

You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.

On clusters running Fedora CoreOS (FCOS), the SSH keys specified in the Ignition config files are written to the /home/core/.ssh/authorized_keys.d/core file. However, the Machine Config Operator manages SSH keys in the /home/core/.ssh/authorized_keys file and configures sshd to ignore the /home/core/.ssh/authorized_keys.d/core file. As a result, newly provisioned OKD nodes are not accessible using SSH until the Machine Config Operator reconciles the machine configs with the authorized_keys file. After you can access the nodes using SSH, you can delete the /home/core/.ssh/authorized_keys.d/core file.

Procedure

  1. If you do not have an SSH key that is configured for password-less authentication on your computer, create one. For example, on a computer that uses a Linux operating system, run the following command:

    1. $ ssh-keygen -t ed25519 -N '' \
    2. -f <path>/<file_name> (1)
    1Specify the path and file name, such as ~/.ssh/id_rsa, of the new SSH key. If you have an existing key pair, ensure your public key is in the your ~/.ssh directory.

    Running this command generates an SSH key that does not require a password in the location that you specified.

    If you plan to install an OKD cluster that uses FIPS Validated / Modules in Process cryptographic libraries on the x86_64 architecture, do not create a key that uses the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.

  2. Start the ssh-agent process as a background task:

    1. $ eval "$(ssh-agent -s)"

    Example output

    1. Agent pid 31874

    If your cluster is in FIPS mode, only use FIPS-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.

  3. Add your SSH private key to the ssh-agent:

    1. $ ssh-add <path>/<file_name> (1)

    Example output

    1. Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
    1Specify the path and file name for your SSH private key, such as ~/.ssh/id_rsa

Next steps

  • When you install OKD, provide the SSH public key to the installation program.

Obtaining the installation program

Before you install OKD, download the installation file on a local computer.

Prerequisites

  • You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure

  1. Download installer from https://github.com/openshift/okd/releases

    The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.

    Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OKD uninstallation procedures for your specific cloud provider.

  2. Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:

    1. $ tar xvf openshift-install-linux.tar.gz
  3. From the Pull Secret page on the Red Hat OpenShift Cluster Manager site, download your installation pull secret as a .txt file. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OKD components.

    Using a pull secret from the Red Hat OpenShift Cluster Manager site is not required. You can use a pull secret for another private registry. Or, if you do not need the cluster to pull images from a private registry, you can use {"auths":{"fake":{"auth":"aWQ6cGFzcwo="}}} as the pull secret when prompted during the installation.

    If you do not use the pull secret from the Red Hat OpenShift Cluster Manager site:

    • Red Hat Operators are not available.

    • The Telemetry and Insights operators do not send data to Red Hat.

    • Content from the Red Hat Container Catalog registry, such as image streams and Operators, are not available.

Installing the OpenShift CLI by downloading the binary

You can install the OpenShift CLI (oc) in order to interact with OKD from a command-line interface. You can install oc on Linux, Windows, or macOS.

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OKD 4.6. Download and install the new version of oc.

Installing the OpenShift CLI on Linux

You can install the OpenShift CLI (oc) binary on Linux by using the following procedure.

Procedure

  1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

  2. Download oc.tar.gz.

  3. Unpack the archive:

    1. $ tar xvzf <file>
  4. Place the oc binary in a directory that is on your PATH.

    To check your PATH, execute the following command:

    1. $ echo $PATH

After you install the OpenShift CLI, it is available using the oc command:

  1. $ oc <command>

Installing the OpenShift CLI on Windows

You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

  1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

  2. Download oc.zip.

  3. Unzip the archive with a ZIP program.

  4. Move the oc binary to a directory that is on your PATH.

    To check your PATH, open the command prompt and execute the following command:

    1. C:\> path

After you install the OpenShift CLI, it is available using the oc command:

  1. C:\> oc <command>

Installing the OpenShift CLI on macOS

You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

  1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

  2. Download oc.tar.gz.

  3. Unpack and unzip the archive.

  4. Move the oc binary to a directory on your PATH.

    To check your PATH, open a terminal and execute the following command:

    1. $ echo $PATH

After you install the OpenShift CLI, it is available using the oc command:

  1. $ oc <command>

Manually creating the installation configuration file

For installations of OKD that use user-provisioned infrastructure, you manually generate your installation configuration file.

Prerequisites

  • Obtain the OKD installation program and the access token for your cluster.

Procedure

  1. Create an installation directory to store your required installation assets in:

    1. $ mkdir <installation_directory>

    You must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OKD version.

  2. Customize the following install-config.yaml file template and save it in the <installation_directory>.

    You must name this configuration file install-config.yaml.

  3. Back up the install-config.yaml file so that you can use it to install multiple clusters.

    The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

Installation configuration parameters

Before you deploy an OKD cluster, you provide parameter values to describe your account on the cloud platform that hosts your cluster and optionally customize your cluster’s platform. When you create the install-config.yaml installation configuration file, you provide values for the required parameters through the command line. If you customize your cluster, you can modify the install-config.yaml file to provide more details about the platform.

After installation, you cannot modify these parameters in the install-config.yaml file.

The openshift-install command does not validate field names for parameters. If an incorrect name is specified, the related file or object is not created, and no error is reported. Ensure that the field names for any parameters that are specified are correct.

Required configuration parameters

Required installation configuration parameters are described in the following table:

Table 7. Required parameters
ParameterDescriptionValues

apiVersion

The API version for the install-config.yaml content. The current version is v1. The installer may also support older API versions.

String

baseDomain

The base domain of your cloud provider. The base domain is used to create routes to your OKD cluster components. The full DNS name for your cluster is a combination of the baseDomain and metadata.name parameter values that uses the <metadata.name>.<baseDomain> format.

A fully-qualified domain or subdomain name, such as example.com.

metadata

Kubernetes resource ObjectMeta, from which only the name parameter is consumed.

Object

metadata.name

The name of the cluster. DNS records for the cluster are all subdomains of {{.metadata.name}}.{{.baseDomain}}.

String of lowercase letters, hyphens (-), and periods (.), such as dev.

platform

The configuration for the specific platform upon which to perform the installation: aws, baremetal, azure, openstack, ovirt, vsphere. For additional information about platform.<platform> parameters, consult the following table for your specific platform.

Object

Network configuration parameters

You can customize your installation configuration based on the requirements of your existing network infrastructure. For example, you can expand the IP address block for the cluster network or provide different IP address blocks than the defaults.

Only IPv4 addresses are supported.

Table 8. Network parameters
ParameterDescriptionValues

networking

The configuration for the cluster network.

Object

You cannot modify parameters specified by the networking object after installation.

networking.networkType

The cluster network provider Container Network Interface (CNI) plug-in to install.

Either OpenShiftSDN or OVNKubernetes. The default value is OVNKubernetes.

networking.clusterNetwork

The IP address blocks for pods.

The default value is 10.128.0.0/14 with a host prefix of /23.

If you specify multiple IP address blocks, the blocks must not overlap.

An array of objects. For example:

  1. networking:
  2. clusterNetwork:
  3. - cidr: 10.128.0.0/14
  4. hostPrefix: 23

networking.clusterNetwork.cidr

Required if you use networking.clusterNetwork. An IP address block.

An IPv4 network.

An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between 0 and 32.

networking.clusterNetwork.hostPrefix

The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23 then each node is assigned a /23 subnet out of the given cidr. A hostPrefix value of 23 provides 510 (2^(32 - 23) - 2) pod IP addresses.

A subnet prefix.

The default value is 23.

networking.serviceNetwork

The IP address block for services. The default value is 172.30.0.0/16.

The OpenShift SDN and OVN-Kubernetes network providers support only a single IP address block for the service network.

An array with an IP address block in CIDR format. For example:

  1. networking:
  2. serviceNetwork:
  3. - 172.30.0.0/16

networking.machineNetwork

The IP address blocks for machines.

If you specify multiple IP address blocks, the blocks must not overlap.

An array of objects. For example:

  1. networking:
  2. machineNetwork:
  3. - cidr: 10.0.0.0/16

networking.machineNetwork.cidr

Required if you use networking.machineNetwork. An IP address block. The default value is 10.0.0.0/16 for all platforms other than libvirt. For libvirt, the default value is 192.168.126.0/24.

An IP network block in CIDR notation.

For example, 10.0.0.0/16.

Set the networking.machineNetwork to match the CIDR that the preferred NIC resides in.

Optional configuration parameters

Optional installation configuration parameters are described in the following table:

Table 9. Optional parameters
ParameterDescriptionValues

additionalTrustBundle

A PEM-encoded X.509 certificate bundle that is added to the nodes’ trusted certificate store. This trust bundle may also be used when a proxy has been configured.

String

compute

The configuration for the machines that comprise the compute nodes.

Array of machine-pool objects. For details, see the following “Machine-pool” table.

compute.architecture

Determines the instruction set architecture of the machines in the pool. Currently, heteregeneous clusters are not supported, so all pools must specify the same architecture. Valid values are amd64 (the default).

String

compute.hyperthreading

Whether to enable or disable simultaneous multithreading, or hyperthreading, on compute machines. By default, simultaneous multithreading is enabled to increase the performance of your machines’ cores.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.

Enabled or Disabled

compute.name

Required if you use compute. The name of the machine pool.

worker

compute.platform

Required if you use compute. Use this parameter to specify the cloud provider to host the worker machines. This parameter value must match the controlPlane.platform parameter value.

aws, azure, gcp, openstack, ovirt, vsphere, or {}

compute.replicas

The number of compute machines, which are also known as worker machines, to provision.

A positive integer greater than or equal to 2. The default value is 3.

controlPlane

The configuration for the machines that comprise the control plane.

Array of MachinePool objects. For details, see the following “Machine-pool” table.

controlPlane.architecture

Determines the instruction set architecture of the machines in the pool. Currently, heterogeneous clusters are not supported, so all pools must specify the same architecture. Valid values are amd64 (the default).

String

controlPlane.hyperthreading

Whether to enable or disable simultaneous multithreading, or hyperthreading, on control plane machines. By default, simultaneous multithreading is enabled to increase the performance of your machines’ cores.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.

Enabled or Disabled

controlPlane.name

Required if you use controlPlane. The name of the machine pool.

master

controlPlane.platform

Required if you use controlPlane. Use this parameter to specify the cloud provider that hosts the control plane machines. This parameter value must match the compute.platform parameter value.

aws, azure, gcp, openstack, ovirt, vsphere, or {}

controlPlane.replicas

The number of control plane machines to provision.

The only supported value is 3, which is the default value.

credentialsMode

The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported.

Not all CCO modes are supported for all cloud providers. For more information on CCO modes, see the Cloud Credential Operator entry in the Red Hat Operators reference content.

Mint, Passthrough, Manual, or an empty string (“”).

imageContentSources

Sources and repositories for the release-image content.

Array of objects. Includes a source and, optionally, mirrors, as described in the following rows of this table.

imageContentSources.source

Required if you use imageContentSources. Specify the repository that users refer to, for example, in image pull specifications.

String

imageContentSources.mirrors

Specify one or more repositories that may also contain the same images.

Array of strings

publish

How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes.

Internal or External. The default value is External.

Setting this field to Internal is not supported on non-cloud platforms.

If the value of the field is set to Internal, the cluster will become non-functional. For more information, refer to BZ#1953035.

sshKey

The SSH key or keys to authenticate access your cluster machines.

For production OKD clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your ssh-agent process uses.

One or more keys. For example:

  1. sshKey:
  2. <key1>
  3. <key2>
  4. <key3>

Sample install-config.yaml file for bare metal

You can customize the install-config.yaml file to specify more details about your OKD cluster’s platform or modify the values of the required parameters.

  1. apiVersion: v1
  2. baseDomain: example.com (1)
  3. compute: (2)
  4. - hyperthreading: Enabled (3)
  5. name: worker
  6. replicas: 0 (4)
  7. controlPlane: (2)
  8. hyperthreading: Enabled (3)
  9. name: master
  10. replicas: 3 (5)
  11. metadata:
  12. name: test (6)
  13. networking:
  14. clusterNetwork:
  15. - cidr: 10.128.0.0/14 (7)
  16. hostPrefix: 23 (8)
  17. networkType: OVNKubernetes
  18. serviceNetwork: (9)
  19. - 172.30.0.0/16
  20. platform:
  21. none: {} (10)
  22. pullSecret: '{"auths": ...}' (11)
  23. sshKey: 'ssh-ed25519 AAAA...' (12)
1The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.
2The controlPlane section is a single mapping, but the compute section is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -, and the first line of the controlPlane section must not. Although both sections currently define a single machine pool, it is possible that future versions of OKD will support defining multiple compute pools during installation. Only one control plane pool is used.
3Whether to enable or disable simultaneous multithreading (SMT), or hyperthreading. By default, SMT is enabled to increase the performance of your machines’ cores. You can disable it by setting the parameter value to Disabled. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.

Simultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the hyperthreading parameter has no effect.

If you disable hyperthreading, whether in the BIOS or in the install-config.yaml, ensure that your capacity planning accounts for the dramatically decreased machine performance.

4You must set the value of the replicas parameter to 0. This parameter controls the number of workers that the cluster creates and manages for you, which are functions that the cluster does not perform when you use user-provisioned infrastructure. You must manually deploy worker machines for the cluster to use before you finish installing OKD.
5The number of control plane machines that you add to the cluster. Because the cluster uses this values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.
6The cluster name that you specified in your DNS records.
7A block of IP addresses from which pod IP addresses are allocated. This block must not overlap with existing physical networks. These IP addresses are used for the pod network. If you need to access the pods from an external network, you must configure load balancers and routers to manage the traffic.
8The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, which allows for 510 (2^(32 - 23) - 2) pod IPs addresses. If you are required to provide access to nodes from an external network, configure load balancers and routers to manage the traffic.
9The IP address pool to use for service IP addresses. You can enter only one IP address pool. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
10You must set the platform to none. You cannot provide additional platform configuration variables for your platform.
11The pull secret that you obtained from the Red Hat OpenShift Cluster Manager site. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OKD components.
12The public portion of the default SSH key for the core user in Fedora CoreOS (FCOS).

For production OKD clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your ssh-agent process uses.

Network configuration phases

When specifying a cluster configuration prior to installation, there are several phases in the installation procedures when you can modify the network configuration:

Phase 1

After entering the openshift-install create install-config command. In the install-config.yaml file, you can customize the following network-related fields:

  • networking.networkType

  • networking.clusterNetwork

  • networking.serviceNetwork

  • networking.machineNetwork

    For more information on these fields, refer to “Installation configuration parameters”.

    Set the networking.machineNetwork to match the CIDR that the preferred NIC resides in.

Phase 2

After entering the openshift-install create manifests command. If you must specify advanced network configuration, during this phase you can define a customized Cluster Network Operator manifest with only the fields you want to modify.

You cannot override the values specified in phase 1 in the install-config.yaml file during phase 2. However, you can further customize the cluster network provider during phase 2.

Specifying advanced network configuration

You can use advanced configuration customization to integrate your cluster into your existing network environment by specifying additional configuration for your cluster network provider. You can specify advanced network configuration only before you install the cluster.

Modifying the OKD manifest files created by the installation program is not supported. Applying a manifest file that you create, as in the following procedure, is supported.

Prerequisites

  • Create the install-config.yaml file and complete any modifications to it.

  • Create the Ignition config files for your cluster.

Procedure

  1. Change to the directory that contains the installation program and create the manifests:

    1. $ ./openshift-install create manifests --dir=<installation_directory>

    where:

    <installation_directory>

    Specifies the name of the directory that contains the install-config.yaml file for your cluster.

  2. Create a stub manifest file for the advanced network configuration that is named cluster-network-03-config.yml in the <installation_directory>/manifests/ directory:

    1. $ cat <<EOF > <installation_directory>/manifests/cluster-network-03-config.yml
    2. apiVersion: operator.openshift.io/v1
    3. kind: Network
    4. metadata:
    5. name: cluster
    6. spec:
    7. EOF

    where:

    <installation_directory>

    Specifies the directory name that contains the manifests/ directory for your cluster.

  3. Open the cluster-network-03-config.yml file in an editor and specify the advanced network configuration for your cluster, such as in the following example:

    Specify a different VXLAN port for the OpenShift SDN network provider

    1. apiVersion: operator.openshift.io/v1
    2. kind: Network
    3. metadata:
    4. name: cluster
    5. spec:
    6. defaultNetwork:
    7. openshiftSDNConfig:
    8. vxlanPort: 4800
  4. Save the cluster-network-03-config.yml file and quit the text editor.

  5. Optional: Back up the manifests/cluster-network-03-config.yml file. The installation program deletes the manifests/ directory when creating the cluster.

Cluster Network Operator configuration

The configuration for the cluster network is specified as part of the Cluster Network Operator (CNO) configuration and stored in a custom resource (CR) object that is named cluster. The CR specifies the fields for the Network API in the operator.openshift.io API group.

The CNO configuration inherits the following fields during cluster installation from the Network API in the Network.config.openshift.io API group and these fields cannot be changed:

clusterNetwork

IP address pools from which pod IP addresses are allocated.

serviceNetwork

IP address pool for services.

defaultNetwork.type

Cluster network provider, such as OpenShift SDN or OVN-Kubernetes.

You can specify the cluster network provider configuration for your cluster by setting the fields for the defaultNetwork object in the CNO object named cluster.

Cluster Network Operator configuration object

The fields for the Cluster Network Operator (CNO) are described in the following table:

Table 10. Cluster Network Operator configuration object
FieldTypeDescription

metadata.name

string

The name of the CNO object. This name is always cluster.

spec.clusterNetwork

array

A list specifying the blocks of IP addresses from which pod IP addresses are allocated and the subnet prefix length assigned to each individual node in the cluster. For example:

  1. spec:
  2. clusterNetwork:
  3. - cidr: 10.128.0.0/19
  4. hostPrefix: 23
  5. - cidr: 10.128.32.0/19
  6. hostPrefix: 23

This value is ready-only and specified in the install-config.yaml file.

spec.serviceNetwork

array

A block of IP addresses for services. The OpenShift SDN and OVN-Kubernetes Container Network Interface (CNI) network providers support only a single IP address block for the service network. For example:

  1. spec:
  2. serviceNetwork:
  3. - 172.30.0.0/14

This value is ready-only and specified in the install-config.yaml file.

spec.defaultNetwork

object

Configures the Container Network Interface (CNI) cluster network provider for the cluster network.

spec.kubeProxyConfig

object

The fields for this object specify the kube-proxy configuration. If you are using the OVN-Kubernetes cluster network provider, the kube-proxy configuration has no effect.

defaultNetwork object configuration

The values for the defaultNetwork object are defined in the following table:

Table 11. defaultNetwork object
FieldTypeDescription

type

string

Either OpenShiftSDN or OVNKubernetes. The cluster network provider is selected during installation. This value cannot be changed after cluster installation.

OKD uses the OVN-Kubernetes Container Network Interface (CNI) cluster network provider by default.

openshiftSDNConfig

object

This object is only valid for the OpenShift SDN cluster network provider.

ovnKubernetesConfig

object

This object is only valid for the OVN-Kubernetes cluster network provider.

Configuration for the OpenShift SDN CNI cluster network provider

The following table describes the configuration fields for the OpenShift SDN Container Network Interface (CNI) cluster network provider.

Table 12. openshiftSDNConfig object
FieldTypeDescription

mode

string

Configures the network isolation mode for OpenShift SDN. The default value is NetworkPolicy.

The values Multitenant and Subnet are available for backwards compatibility with OKD 3.x but are not recommended. This value cannot be changed after cluster installation.

mtu

integer

The maximum transmission unit (MTU) for the VXLAN overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU.

If the auto-detected value is not what you expected it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes.

If your cluster requires different MTU values for different nodes, you must set this value to 50 less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of 9001, and some have an MTU of 1500, you must set this value to 1450.

This value cannot be changed after cluster installation.

vxlanPort

integer

The port to use for all VXLAN packets. The default value is 4789. This value cannot be changed after cluster installation.

If you are running in a virtualized environment with existing nodes that are part of another VXLAN network, then you might be required to change this. For example, when running an OpenShift SDN overlay on top of VMware NSX-T, you must select an alternate port for the VXLAN, because both SDNs use the same default VXLAN port number.

On Amazon Web Services (AWS), you can select an alternate port for the VXLAN between port 9000 and port 9999.

Example OpenShift SDN configuration

  1. defaultNetwork:
  2. type: OpenShiftSDN
  3. openshiftSDNConfig:
  4. mode: NetworkPolicy
  5. mtu: 1450
  6. vxlanPort: 4789
Configuration for the OVN-Kubernetes CNI cluster network provider

The following table describes the configuration fields for the OVN-Kubernetes CNI cluster network provider.

Table 13. ovnKubernetesConfig object
FieldTypeDescription

mtu

integer

The maximum transmission unit (MTU) for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU.

If the auto-detected value is not what you expected it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes.

If your cluster requires different MTU values for different nodes, you must set this value to 100 less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of 9001, and some have an MTU of 1500, you must set this value to 1400.

This value cannot be changed after cluster installation.

genevePort

integer

The port to use for all Geneve packets. The default value is 6081. This value cannot be changed after cluster installation.

Example OVN-Kubernetes configuration

  1. defaultNetwork:
  2. type: OVNKubernetes
  3. ovnKubernetesConfig:
  4. mtu: 1400
  5. genevePort: 6081

kubeProxyConfig object configuration

The values for the kubeProxyConfig object are defined in the following table:

Table 14. kubeProxyConfig object
FieldTypeDescription

iptablesSyncPeriod

string

The refresh period for iptables rules. The default value is 30s. Valid suffixes include s, m, and h and are described in the Go time package documentation.

Because of performance improvements introduced in OKD 4.3 and greater, adjusting the iptablesSyncPeriod parameter is no longer necessary.

proxyArguments.iptables-min-sync-period

array

The minimum duration before refreshing iptables rules. This field ensures that the refresh does not happen too frequently. Valid suffixes include s, m, and h and are described in the Go time package. The default value is:

  1. kubeProxyConfig:
  2. proxyArguments:
  3. iptables-min-sync-period:
  4. - 0s

Creating the Ignition config files

Because you must manually start the cluster machines, you must generate the Ignition config files that the cluster needs to make its machines.

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

Prerequisites

  • Obtain the OKD installation program and the pull secret for your cluster.

Procedure

  • Obtain the Ignition config files:

    1. $ ./openshift-install create ignition-configs --dir=<installation_directory> (1)
    1For <installation_directory>, specify the directory name to store the files that the installation program creates.

    If you created an install-config.yaml file, specify the directory that contains it. Otherwise, specify an empty directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OKD version.

    The following files are generated in the directory:

    1. .
    2. ├── auth
    3. ├── kubeadmin-password
    4. └── kubeconfig
    5. ├── bootstrap.ign
    6. ├── master.ign
    7. ├── metadata.json
    8. └── worker.ign

Creating Fedora CoreOS (FCOS) machines

Before you install a cluster on bare metal infrastructure that you provision, you must create FCOS machines for it to use. To create the machines, follow either the steps to use an ISO image or network PXE booting.

There are several methods of configuring FCOS during ISO and PXE installations. These include:

  • Kernel arguments: For a PXE install, you can APPEND arguments to the kernel of the live installer. For an ISO install, you can interrupt the live installation boot process to add kernel arguments. In both cases, you can use special coreos.inst.* arguments to direct the installer, as well as standard boot arguments for turning standard kernel services on or off.

  • Ignition configs: You must generate an OKD Ignition config file (*.ign) for the type of node you are installing (worker, control plane, or bootstrap). You pass the location of the Ignition config to the installed system so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by the installer and should not be used to include the standard worker and master Ignition configs.

  • coreos-installer: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run the coreos-installer command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.

Whether to use an ISO or PXE install depends on your situation. A PXE install requires an available DHCP service and more preparation, but can make the installation process more automated. An ISO install is a more manual process and can be inconvenient if you are setting up more than a few machines.

Creating Fedora CoreOS (FCOS) machines using an ISO image

Before you install a cluster on infrastructure that you provision, you must create FCOS machines for it to use. You can use an ISO image to create the machines.

Prerequisites

  • Obtain the Ignition config files for your cluster.

  • Have access to an HTTP server that can be accessed from your computer, and from the machines that you create.

Procedure

  1. Upload the control plane, compute, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.

    If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

  2. Obtain the FCOS images from the FCOS Downloads page

  3. Use the ISO to start the FCOS installation. Use one of the following installation options:

    • Burn the ISO image to a disk and boot it directly.

    • Use ISO redirection via a LOM interface.

  4. Boot the ISO image. You can interrupt the installation boot process to add kernel arguments. However, for this ISO procedure you should use the coreos-installer command instead of adding kernel arguments. If you run the live installer without options or interruption, the installer boots up to a shell prompt on the live system, ready for you to install FCOS to disk.

  5. Review the Advanced FCOS installation reference section for different ways of configuring features, such as networking and disk partitions, before running the coreos-installer.

  6. Run the coreos-installer command. At a minimum, you must identify the Ignition config file location for your node type, and the location of the disk you are installing to. Here is an example:

    1. $ sudo coreos-installer install \
    2. --ignition-url=https://host/worker.ign /dev/sda
  7. After FCOS installs, the system reboots. During the system reboot, it applies the Ignition config file that you specified.

  8. Continue to create the other machines for your cluster.

    You must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, which is the default, also create at least two compute machines before you install the cluster.

Creating Fedora CoreOS (FCOS) machines by PXE or iPXE booting

Before you install a cluster that uses manually-provisioned FCOS nodes, such as bare metal, you must create FCOS machines for it to use. You can use PXE or iPXE booting to create the machines.

Prerequisites

  • Obtain the Ignition config files for your cluster.

  • Configure suitable PXE or iPXE infrastructure.

  • Have access to an HTTP server that you can access from your computer.

Procedure

  1. Upload the master, worker, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.

    You can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

  2. Obtain the FCOS kernel, initramfs and rootfs files from the FCOS Downloads page

  3. Upload the additional files that are required for your booting method:

    • For traditional PXE, upload the kernel and initramfs files to your TFTP server and the rootfs file to your HTTP server.

    • For iPXE, upload the kernel, initramfs, and rootfs files to your HTTP server.

      If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

  4. Configure the network boot infrastructure so that the machines boot from their local disks after FCOS is installed on them.

  5. Configure PXE or iPXE installation for the FCOS images.

    Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:

    • For PXE:

      1. DEFAULT pxeboot
      2. TIMEOUT 20
      3. PROMPT 0
      4. LABEL pxeboot
      5. KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> (1)
      6. APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign (2) (3)
      1Specify the location of the live kernel file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported.
      2If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
      3Specify locations of the FCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the initramfs file, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to the APPEND line to configure networking or other boot options.

      This configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more console= arguments to the APPEND line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?.

    • For iPXE:

      1. kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign (1) (2)
      2. initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img (3)
      3. boot
      1Specify locations of the FCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file.
      2If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
      3Specify the location of the initramfs file that you uploaded to your HTTP server.

      This configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more console= arguments to the kernel line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?.

  6. If you use PXE UEFI, perform the following actions:

    1. Provide the shimx64.efi and grubx64.efi EFI binaries and the grub.cfg file that are required for booting the system.

      • Extract the necessary EFI binaries by mounting the FCOS ISO to your host and then mounting the images/efiboot.img file to your host:

        1. $ mkdir -p /mnt/iso
        1. $ mkdir -p /mnt/efiboot
        1. $ mount -o loop rhcos-installer.x86_64.iso /mnt/iso
        1. $ mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot
      • From the efiboot.img mount point, copy the EFI/redhat/shimx64.efi and EFI/redhat/grubx64.efi files to your TFTP server:

        1. $ cp /mnt/efiboot/EFI/redhat/shimx64.efi .
        1. $ cp /mnt/efiboot/EFI/redhat/grubx64.efi .
        1. $ umount /mnt/efiboot
        1. $ umount /mnt/iso
      • Copy the EFI/redhat/grub.cfg file that is included in the FCOS ISO to your TFTP server.

    2. Edit the grub.cfg file to include arguments similar to the following:

      1. menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os {
      2. linuxefi rhcos-<version>-live-kernel-<architecture> coreos.inst.install_dev=/dev/sda coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign
      3. initrdefi rhcos-<version>-live-initramfs.<architecture>.img
      4. }

      where:

      rhcos-<version>-live-kernel-<architecture>

      Specifies the kernel file that you uploaded to your TFTP server.

      http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img

      Specifies the location of the live rootfs image that you uploaded to your HTTP server.

      http://<HTTP_server>/bootstrap.ign

      Specifies the location of the bootstrap Ignition config file that you uploaded to your HTTP server.

      rhcos-<version>-live-initramfs.<architecture>.img

      Specifies the location of the initramfs file that you uploaded to your TFTP server.

      For more information on how to configure a PXE server for UEFI boot, see the Red Hat Knowledgebase article: How to configure/setup a PXE server for UEFI boot for Red Hat Enterprise Linux?.

  7. Continue to create the machines for your cluster.

    You must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, which is the default, also create at least two compute machines before you install the cluster.

Advanced Fedora CoreOS (FCOS) installation configuration

A key benefit for manually provisioning the Fedora CoreOS (FCOS) nodes for OKD is to be able to do configuration that is not available through default OKD installation methods. This section describes some of the configurations that you can do using techniques that include:

  • Passing kernel arguments to the live installer

  • Running coreos-installer manually from the live system

  • Embedding Ignition configs in an ISO

The advanced configuration topics for manual Fedora CoreOS (FCOS) installations detailed in this section relate to disk partitioning, networking, and using Ignition configs in different ways.

Using advanced networking options for PXE and ISO installations

Networking for OKD nodes uses DHCP by default to gather all necessary configuration settings. To set up static IP addresses or configure special settings, such as bonding, you can do one of the following:

  • Pass special kernel parameters when you boot the live installer.

  • Use a machine config to copy networking files to the installed system.

  • Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.

To configure a PXE or iPXE installation, use one of the following options:

  • See the “Advanced RHCOS installation reference” tables.

  • Use a machine config to copy networking files to the installed system.

To configure an ISO installation, use the following procedure.

Procedure

  1. Boot the ISO installer.

  2. From the live system shell prompt, configure networking for the live system using available RHEL tools, such as nmcli or nmtui.

  3. Run the coreos-installer command to install the system, adding the --copy-network option to copy networking configuration. For example:

    1. $ coreos-installer install --copy-network \
    2. --ignition-url=http://host/worker.ign /dev/sda

    The —copy-network option only copies networking configuration found under /etc/NetworkManager/system-connections. In particular, it does not copy the system hostname.

  4. Reboot into the installed system.

Disk partitioning

The disk partitions are created on OKD cluster nodes during the Fedora CoreOS (FCOS) installation. Each FCOS node of a particular architecture uses the same partition layout, unless the default partitioning configuration is overridden. During the FCOS installation, the size of the root file system is increased to use the remaining available space on the target device.

However, there are two cases where you might want to intervene to override the default partitioning when installing an OKD node:

  • Create separate partitions: For greenfield installations on an empty disk, you might want to add separate storage to a partition. This is officially supported for making /var or a subdirectory of /var, such as /var/lib/etcd, a separate partition, but not both.

    Kubernetes supports only two filesystem partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them.

  • Retain existing partitions: For a brownfield installation where you are reinstalling OKD on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to coreos-installer that allow you to retain existing data partitions.

Creating a separate /var partition

In general, disk partitioning for OKD should be left to the installer. However, there are cases where you might want to create separate partitions in a part of the filesystem that you expect to grow.

OKD supports the addition of a single partition to attach storage to either the /var partition or a subdirectory of /var. For example:

  • /var/lib/containers: Holds container-related content that can grow as more images and containers are added to a system.

  • /var/lib/etcd: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage.

  • /var: Holds data that you might want to keep separate for purposes such as auditing.

Storing the contents of a /var directory separately makes it easier to grow storage for those areas as needed and reinstall OKD at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.

Because /var must be in place before a fresh installation of Fedora CoreOS (FCOS), the following procedure sets up the separate /var partition by creating a machine config that is inserted during the openshift-install preparation phases of an OKD installation.

Procedure

  1. Create a directory to hold the OKD installation files:

    1. $ mkdir $HOME/clusterconfig
  2. Run openshift-install to create a set of files in the manifest and openshift subdirectories. Answer the system questions as you are prompted:

    1. $ openshift-install create manifests --dir $HOME/clusterconfig
    2. ? SSH Public Key ...
    3. $ ls $HOME/clusterconfig/openshift/
    4. 99_kubeadmin-password-secret.yaml
    5. 99_openshift-cluster-api_master-machines-0.yaml
    6. 99_openshift-cluster-api_master-machines-1.yaml
    7. 99_openshift-cluster-api_master-machines-2.yaml
    8. ...
  3. Create a MachineConfig object and add it to a file in the openshift directory. For example, name the file 98-var-partition.yaml, change the disk device name to the name of the storage device on the worker systems, and set the storage size as appropriate. This attaches storage to a separate /var directory.

    1. apiVersion: machineconfiguration.openshift.io/v1
    2. kind: MachineConfig
    3. metadata:
    4. labels:
    5. machineconfiguration.openshift.io/role: worker
    6. name: 98-var-partition
    7. spec:
    8. config:
    9. ignition:
    10. version: 3.1.0
    11. storage:
    12. disks:
    13. - device: /dev/<device_name> (1)
    14. partitions:
    15. - sizeMiB: <partition_size>
    16. startMiB: <partition_start_offset> (2)
    17. label: var
    18. filesystems:
    19. - path: /var
    20. device: /dev/disk/by-partlabel/var
    21. format: xfs
    22. systemd:
    23. units:
    24. - name: var.mount
    25. enabled: true
    26. contents: |
    27. [Unit]
    28. Before=local-fs.target
    29. [Mount]
    30. Where=/var
    31. What=/dev/disk/by-partlabel/var
    32. [Install]
    33. WantedBy=local-fs.target
    1The storage device name of the disk that you want to partition.
    2When adding a data partition to the boot disk, a minimum value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of FCOS might overwrite the beginning of the data partition.

    When creating a separate /var partition, you cannot use different instance types for worker nodes, if the different instance types do not have the same device name.

  4. Run openshift-install again to create Ignition configs from a set of files in the manifest and openshift subdirectories:

    1. $ openshift-install create ignition-configs --dir $HOME/clusterconfig
    2. $ ls $HOME/clusterconfig/
    3. auth bootstrap.ign master.ign metadata.json worker.ign

Now you can use the Ignition config files as input to the ISO or PXE manual installation procedures to install Fedora CoreOS (FCOS) systems.

Retaining existing partitions

For an ISO installation, you can add options to the coreos-installer command line that causes the installer to maintain one or more existing partitions. For a PXE installation, you can APPEND coreos.inst.* options to preserve partitions.

Saved partitions might be partitions from an existing OKD system that has data partitions that you want to keep. Here are a few tips:

  • If you save existing partitions, and those partitions do not leave enough space for FCOS, installation will fail without damaging the saved partitions.

  • Identify the disk partitions you want to keep either by partition label or by number.

For an ISO installation

This example preserves any partition in which the partition label begins with data (data*):

  1. # coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
  2. --save-partlabel 'data*' /dev/sda

The following example illustrates running the coreos-installer in a way that preserves the sixth (6) partition on the disk:

  1. # coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
  2. --save-partindex 6 /dev/sda

This example preserves partitions 5 and higher:

  1. # coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign
  2. --save-partindex 5- /dev/sda

In the previous examples where partition saving is used, coreos-installer recreates the partition immediately.

For a PXE installation

This APPEND option preserves any partition in which the partition label begins with ‘data’ (‘data*‘):

  1. coreos.inst.save_partlabel=data*

This APPEND option preserves partitions 5 and higher:

  1. coreos.inst.save_partindex=5-

This APPEND option preserves partition 6:

  1. coreos.inst.save_partindex=6

Identifying Ignition configs

When doing an FCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:

  • Permanent install Ignition config: Every manual FCOS installation needs to pass one of the Ignition config files generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, to carry out the installation.

    It is not recommended to modify these files.

    For PXE installations, you pass the Ignition configs on the APPEND line using the coreos.inst.ignition_url= option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on the coreos-installer command line with the --ignition-url= option. In both cases, only HTTP and HTTPS protocols are supported.

  • Live install Ignition config: This type must be created manually and should be avoided if possible, as it is not supported by Red Hat. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before and/or after the FCOS system installs to disk. This method should only be used for performing tasks that must be performed once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.

    For PXE or ISO boots, you can create the Ignition config and APPEND the ignition.config.url= option to identify the location of the Ignition config. You also need to append ignition.firstboot ignition.platform.id=metal or the ignition.config.url option will be ignored.

Embedding an Ignition config in the FCOS ISO

You can embed a live install Ignition config directly in an FCOS ISO image. When the ISO image is booted, the embedded config will be applied automatically.

Procedure

  1. Download the coreos-installer binary from the following image mirror page: https://mirror.openshift.com/pub/openshift-v4/clients/coreos-installer/latest/.

  2. Retrieve the FCOS ISO image and the Ignition config file, and copy them into an accessible directory, such as /mnt:

    1. # cp rhcos-<version>-live.x86_64.iso bootstrap.ign /mnt/
    2. # chmod 644 /mnt/rhcos-<version>-live.x86_64.iso
  3. Run the following command to embed the Ignition config into the ISO:

    1. # ./coreos-installer iso ignition embed -i /mnt/bootstrap.ign \
    2. /mnt/rhcos-<version>-live.x86_64.iso

    You can now use that ISO to install FCOS using the specified live install Ignition config.

    Using coreos-installer iso ignition embed to embed a file generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, is unsupported and not recommended.

  4. To show the contents of the embedded Ignition config and direct it into a file, run:

    1. # ./coreos-installer iso ignition show /mnt/rhcos-<version>-live.x86_64.iso > mybootstrap.ign
    1. # diff -s bootstrap.ign mybootstrap.ign

    Example output

    1. Files bootstrap.ign and mybootstrap.ign are identical
  5. To remove the Ignition config and return the ISO to its pristine state so you can reuse it, run:

    1. # ./coreos-installer iso ignition remove /mnt/rhcos-<version>-live.x86_64.iso

    You can now embed another Ignition config into the ISO or use the ISO in its pristine state.

Advanced FCOS installation reference

This section illustrates the networking configuration and other advanced options that allow you to modify the Fedora CoreOS (FCOS) manual installation process. The following tables describe the kernel arguments and command-line options you can use with the FCOS live installer and the coreos-installer command.

Routing and bonding options at FCOS boot prompt

If you install FCOS from an ISO image, you can add kernel arguments manually when you boot that image to configure the node’s networking. If no networking arguments are used, the installation defaults to using DHCP.

When adding networking arguments, you must also add the rd.neednet=1 kernel argument.

The following table describes how to use ip=, nameserver=, and bond= kernel arguments for live ISO installs.

Ordering is important when adding kernel arguments: ip=, nameserver=, and then bond=.

Routing and bonding options for ISO

The following table provides examples for configuring networking of your Fedora CoreOS (FCOS) nodes. These are networking options that are passed to the dracut tool during system boot. For more information about the networking options supported by dracut, see the dracut.cmdline manual page.

DescriptionExamples

To configure an IP address, either use DHCP (ip=dhcp) or set an individual static IP address (ip=<host_ip>). Then identify the DNS server IP address (nameserver=<dns_ip>) on each node. This example sets:

  • The node’s IP address to 10.10.10.2

  • The gateway address to 10.10.10.254

  • The netmask to 255.255.255.0

  • The hostname to core0.example.com

  • The DNS server address to 4.4.4.41

  1. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
  2. nameserver=4.4.4.41

Specify multiple network interfaces by specifying multiple ip= entries.

  1. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
  2. ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none

Disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used.

  1. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none
  2. ip=::::core0.example.com:enp2s0:none

You can combine DHCP and static IP configurations on systems with multiple network interfaces.

  1. ip=enp1s0:dhcp
  2. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none

Optional: You can configure VLANs on individual interfaces by using the vlan= parameter.

To configure a VLAN on a network interface and use a static IP address:

  1. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none
  2. vlan=enp2s0.100:enp2s0

To configure a VLAN on a network interface and to use DHCP:

  1. ip=enp2s0.100:dhcp
  2. vlan=enp2s0.100:enp2s0

You can provide multiple DNS servers by adding a nameserver= entry for each server.

  1. nameserver=1.1.1.1
  2. nameserver=8.8.8.8

Optional: Bonding multiple network interfaces to a single interface is supported using the bond= option. In these two examples:

  • The syntax for configuring a bonded interface is: bond=name[:network_interfaces][:options]

  • name is the bonding device name (bond0), network_interfaces represents a comma-separated list of physical (ethernet) interfaces (em1,em2), and options is a comma-separated list of bonding options. Enter modinfo bonding to see available options.

  • When you create a bonded interface using bond=, you must specify how the IP address is assigned and other information for the bonded interface.

To configure the bonded interface to use DHCP, set the bond’s IP address to dhcp. For example:

  1. bond=bond0:em1,em2:mode=active-backup
  2. ip=bond0:dhcp

To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:

  1. bond=bond0:em1,em2:mode=active-backup
  2. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none

Optional: You can configure VLANs on bonded interfaces by using the vlan= parameter.

To configure the bonded interface with a VLAN and to use DHCP:

  1. ip=bond0.100:dhcp
  2. bond=bond0:em1,em2:mode=active-backup
  3. vlan=bond0.100:bond0

To configure the bonded interface with a VLAN and to use a static IP address:

  1. ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0.100:none
  2. bond=bond0:em1,em2:mode=active-backup
  3. vlan=bond0.100:bond0
coreos.inst boot options for ISO or PXE install

While you can pass most standard installation boot arguments to the live installer, there are several arguments that are specific to the FCOS live installer.

  • For ISO, these options can be added by interrupting the FCOS installer.

  • For PXE or iPXE, these options must be added to the APPEND line before starting the PXE kernel. You cannot interrupt a live PXE install.

The following table shows the FCOS live installer boot options for ISO and PXE installs.

Table 15. coreos.inst boot options
ArgumentDescription

coreos.inst.install_dev

Required. The block device on the system to install to. It is recommended to use the full path, such as /dev/sda, although sda is allowed.

coreos.inst.ignition_url

Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded.

coreos.inst.save_partlabel

Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist.

coreos.inst.save_partindex

Optional: Comma-separated indexes of partitions to preserve during the install. Ranges m-n are permitted, and either m or n can be omitted. The specified partitions do not need to exist.

coreos.inst.insecure

Optional: Permits the OS image that is specified by coreos.inst.image_url to be unsigned.

coreos.inst.image_url

Optional: Download and install the specified FCOS image.

  • This argument should not be used in production environments and is intended for debugging purposes only.

  • While this argument can be used to install a version of FCOS that does not match the live media, it is recommended that you instead use the media that matches the version you want to install.

  • If you are using coreos.inst.image_url, you must also use coreos.inst.insecure. This is because the bare-metal media are not GPG-signed for OKD.

  • Only HTTP and HTTPS protocols are supported.

coreos.inst.skip_reboot

Optional: The system will not reboot after installing. Once the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only.

coreos.inst.platform_id

Optional: The Ignition platform ID of the platform the FCOS image is being installed on. Default is metal. This option determines whether or not to request an Ignition config from the cloud provider, such as VMware. For example: coreos.inst.platform_id=vmware.

ignition.config.url

Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how coreos-installer is invoked, or to run code before or after the installation. This is different from coreos.inst.ignition_url, which is the Ignition config for the installed system.

coreos-installer options for ISO install

You can also install FCOS by invoking the coreos-installer command directly from the command line. The kernel arguments in the previous table provide a shortcut for automatically invoking coreos-installer at boot time, but you can pass similar arguments directly to coreos-installer when running it from a shell prompt.

The following table shows the options and subcommands you can pass to the coreos-installer command from a shell prompt during a live install.

Table 16. coreos-installer command-line options, arguments, and subcommands

Command-line options

Option

Description

-u, —image-url <url>

Specify the image URL manually.

-f, —image-file <path>

Specify a local image file manually.

-i, —ignition-file <path>

Embed an Ignition config from a file.

-I, —ignition-url <URL>

Embed an Ignition config from a URL.

—ignition-hash <digest>

Digest type-value of the Ignition config.

-p, —platform <name>

Override the Ignition platform ID.

—append-karg <arg>…​

Append the default kernel argument.

—delete-karg <arg>…​

Delete the default kernel argument.

-n, —copy-network

Copy the network configuration from the install environment.

+

The —copy-network option only copies networking configuration found under /etc/NetworkManager/system-connections. In particular, it does not copy the system hostname.

—network-dir <path>

For use with -n. Default is /etc/NetworkManager/system-connections/.

—save-partlabel <lx>..

Save partitions with this label glob.

—save-partindex <id>…​

Save partitions with this number or range.

—offline

Force offline installation.

—insecure

Skip signature verification.

—insecure-ignition

Allow Ignition URL without HTTPS or hash.

—architecture <name>

Target CPU architecture. Default is x86_64.

—preserve-on-error

Do not clear partition table on error.

-h, —help

Print help information.

Command-line argument

Argument

Description

<device>

The destination device.

coreos-installer embedded Ignition commands

Command

Description

$ coreos-installer iso ignition embed <options> —ignition-file <file_path> <ISO_image>

Embed an Ignition config in an ISO image.

coreos-installer iso ignition show <options> <ISO_image>

Show the embedded Ignition config from an ISO image.

coreos-installer iso ignition remove <options> <ISO_image>

Remove the embedded Ignition config from an ISO image.

coreos-installer ISO Ignition options

Option

Description

-f, —force

Overwrite an existing Ignition config.

-i, —ignition-file <path>

The Ignition config to be used. Default is stdin.

-o, —output <path>

Write the ISO to a new output file.

-h, —help

Print help information.

coreos-installer PXE Ignition commands

Command

Description

Note that not all of these options are accepted by all subcommands.

coreos-installer pxe ignition wrap <options>

Wrap an Ignition config in an image.

coreos-installer pxe ignition unwrap <options> <image_name>

Show the wrapped Ignition config in an image.

coreos-installer pxe ignition unwrap <options> <initrd_name>

Show the wrapped Ignition config in an initrd image.

coreos-installer PXE Ignition options

Option

Description

-i, —ignition-file <path>

The Ignition config to be used. Default is stdin.

-o, —output <path>

Write the ISO to a new output file.

-h, —help

Print help information.

Creating the cluster

To create the OKD cluster, you wait for the bootstrap process to complete on the machines that you provisioned by using the Ignition config files that you generated with the installation program.

Prerequisites

  • Create the required infrastructure for the cluster.

  • You obtained the installation program and generated the Ignition config files for your cluster.

  • You used the Ignition config files to create FCOS machines for your cluster.

  • Your machines have direct Internet access or have an HTTP or HTTPS proxy available.

Procedure

  1. Monitor the bootstrap process:

    1. $ ./openshift-install --dir=<installation_directory> wait-for bootstrap-complete \ (1)
    2. --log-level=info (2)
    1For <installation_directory>, specify the path to the directory that you stored the installation files in.
    2To view different installation details, specify warn, debug, or error instead of info.

    Example output

    1. INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
    2. INFO API v1.19.0 up
    3. INFO Waiting up to 30m0s for bootstrapping to complete...
    4. INFO It is now safe to remove the bootstrap resources

    The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.

  2. After bootstrap process is complete, remove the bootstrap machine from the load balancer.

    You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

Logging in to the cluster by using the CLI

You can log in to your cluster as a default system user by exporting the cluster kubeconfig file. The kubeconfig file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OKD installation.

Prerequisites

  • You deployed an OKD cluster.

  • You installed the oc CLI.

Procedure

  1. Export the kubeadmin credentials:

    1. $ export KUBECONFIG=<installation_directory>/auth/kubeconfig (1)
    1For <installation_directory>, specify the path to the directory that you stored the installation files in.
  2. Verify you can run oc commands successfully using the exported configuration:

    1. $ oc whoami

    Example output

    1. system:admin

Approving the certificate signing requests for your machines

When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.

Prerequisites

  • You added machines to your cluster.

Procedure

  1. Confirm that the cluster recognizes the machines:

    1. $ oc get nodes

    Example output

    1. NAME STATUS ROLES AGE VERSION
    2. master-0 Ready master 63m v1.19.0
    3. master-1 Ready master 63m v1.19.0
    4. master-2 Ready master 64m v1.19.0
    5. worker-0 NotReady worker 76s v1.19.0
    6. worker-1 NotReady worker 70s v1.19.0

    The output lists all of the machines that you created.

    The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

  2. Review the pending CSRs and ensure that you see the client requests with the Pending or Approved status for each machine that you added to the cluster:

    1. $ oc get csr

    Example output

    1. NAME AGE REQUESTOR CONDITION
    2. csr-8b2br 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending
    3. csr-8vnps 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending
    4. ...

    In this example, two machines are joining the cluster. You might see more approved CSRs in the list.

  3. If the CSRs were not approved, after all of the pending CSRs for the machines you added are in Pending status, approve the CSRs for your cluster machines:

    Because the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. Once the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the machine-approver if the Kubelet requests a new certificate with identical parameters.

    For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.

    • To approve them individually, run the following command for each valid CSR:

      1. $ oc adm certificate approve <csr_name> (1)
      1<csr_name> is the name of a CSR from the list of current CSRs.
    • To approve all pending CSRs, run the following command:

      1. $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve

      Some Operators might not become available until some CSRs are approved.

  4. Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

    1. $ oc get csr

    Example output

    1. NAME AGE REQUESTOR CONDITION
    2. csr-bfd72 5m26s system:node:ip-10-0-50-126.us-east-2.compute.internal Pending
    3. csr-c57lv 5m26s system:node:ip-10-0-95-157.us-east-2.compute.internal Pending
    4. ...
  5. If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:

    • To approve them individually, run the following command for each valid CSR:

      1. $ oc adm certificate approve <csr_name> (1)
      1<csr_name> is the name of a CSR from the list of current CSRs.
    • To approve all pending CSRs, run the following command:

      1. $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
  6. After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

    1. $ oc get nodes

    Example output

    1. NAME STATUS ROLES AGE VERSION
    2. master-0 Ready master 73m v1.20.0
    3. master-1 Ready master 73m v1.20.0
    4. master-2 Ready master 74m v1.20.0
    5. worker-0 Ready worker 11m v1.20.0
    6. worker-1 Ready worker 11m v1.20.0

    It can take a few minutes after approval of the server CSRs for the machines to transition to the Ready status.

Additional information

Initial Operator configuration

After the control plane initializes, you must immediately configure some Operators so that they all become available.

Prerequisites

  • Your control plane has initialized.

Procedure

  1. Watch the cluster components come online:

    1. $ watch -n5 oc get clusteroperators

    Example output

    1. NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE
    2. authentication 4.6.0 True False False 3h56m
    3. cloud-credential 4.6.0 True False False 29h
    4. cluster-autoscaler 4.6.0 True False False 29h
    5. config-operator 4.6.0 True False False 6h39m
    6. console 4.6.0 True False False 3h59m
    7. csi-snapshot-controller 4.6.0 True False False 4h12m
    8. dns 4.6.0 True False False 4h15m
    9. etcd 4.6.0 True False False 29h
    10. image-registry 4.6.0 True False False 3h59m
    11. ingress 4.6.0 True False False 4h30m
    12. insights 4.6.0 True False False 29h
    13. kube-apiserver 4.6.0 True False False 29h
    14. kube-controller-manager 4.6.0 True False False 29h
    15. kube-scheduler 4.6.0 True False False 29h
    16. kube-storage-version-migrator 4.6.0 True False False 4h2m
    17. machine-api 4.6.0 True False False 29h
    18. machine-approver 4.6.0 True False False 6h34m
    19. machine-config 4.6.0 True False False 3h56m
    20. marketplace 4.6.0 True False False 4h2m
    21. monitoring 4.6.0 True False False 6h31m
    22. network 4.6.0 True False False 29h
    23. node-tuning 4.6.0 True False False 4h30m
    24. openshift-apiserver 4.6.0 True False False 3h56m
    25. openshift-controller-manager 4.6.0 True False False 4h36m
    26. openshift-samples 4.6.0 True False False 4h30m
    27. operator-lifecycle-manager 4.6.0 True False False 29h
    28. operator-lifecycle-manager-catalog 4.6.0 True False False 29h
    29. operator-lifecycle-manager-packageserver 4.6.0 True False False 3h59m
    30. service-ca 4.6.0 True False False 29h
    31. storage 4.6.0 True False False 4h30m
  2. Configure the Operators that are not available.

Image registry removed during installation

On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed. This allows openshift-installer to complete installations on these platform types.

After installation, you must edit the Image Registry Operator configuration to switch the managementState from Removed to Managed.

The Prometheus console provides an ImageRegistryRemoved alert, for example:

“Image Registry has been removed. ImageStreamTags, BuildConfigs and DeploymentConfigs which reference ImageStreamTags may not work as expected. Please configure storage and update the config to Managed state by editing configs.imageregistry.operator.openshift.io.”

Image registry storage configuration

The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.

Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

Configuring block registry storage

To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Block storage volumes are supported but not recommended for use with the image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.

Procedure

  1. To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only one (1) replica:

    1. $ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
  2. Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.

  3. Edit the registry configuration so that it references the correct PVC.

Completing installation on user-provisioned infrastructure

After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.

Prerequisites

  • Your control plane has initialized.

  • You have completed the initial Operator configuration.

Procedure

  1. Confirm that all the cluster components are online with the following command:

    1. $ watch -n5 oc get clusteroperators

    Example output

    1. NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE
    2. authentication 4.6.0 True False False 3h56m
    3. cloud-credential 4.6.0 True False False 29h
    4. cluster-autoscaler 4.6.0 True False False 29h
    5. config-operator 4.6.0 True False False 6h39m
    6. console 4.6.0 True False False 3h59m
    7. csi-snapshot-controller 4.6.0 True False False 4h12m
    8. dns 4.6.0 True False False 4h15m
    9. etcd 4.6.0 True False False 29h
    10. image-registry 4.6.0 True False False 3h59m
    11. ingress 4.6.0 True False False 4h30m
    12. insights 4.6.0 True False False 29h
    13. kube-apiserver 4.6.0 True False False 29h
    14. kube-controller-manager 4.6.0 True False False 29h
    15. kube-scheduler 4.6.0 True False False 29h
    16. kube-storage-version-migrator 4.6.0 True False False 4h2m
    17. machine-api 4.6.0 True False False 29h
    18. machine-approver 4.6.0 True False False 6h34m
    19. machine-config 4.6.0 True False False 3h56m
    20. marketplace 4.6.0 True False False 4h2m
    21. monitoring 4.6.0 True False False 6h31m
    22. network 4.6.0 True False False 29h
    23. node-tuning 4.6.0 True False False 4h30m
    24. openshift-apiserver 4.6.0 True False False 3h56m
    25. openshift-controller-manager 4.6.0 True False False 4h36m
    26. openshift-samples 4.6.0 True False False 4h30m
    27. operator-lifecycle-manager 4.6.0 True False False 29h
    28. operator-lifecycle-manager-catalog 4.6.0 True False False 29h
    29. operator-lifecycle-manager-packageserver 4.6.0 True False False 3h59m
    30. service-ca 4.6.0 True False False 29h
    31. storage 4.6.0 True False False 4h30m

    Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:

    1. $ ./openshift-install --dir=<installation_directory> wait-for install-complete (1)
    1For <installation_directory>, specify the path to the directory that you stored the installation files in.

    Example output

    1. INFO Waiting up to 30m0s for the cluster to initialize...

    The command succeeds when the Cluster Version Operator finishes deploying the OKD cluster from Kubernetes API server.

    The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

  2. Confirm that the Kubernetes API server is communicating with the pods.

    1. To view a list of all pods, use the following command:

      1. $ oc get pods --all-namespaces

      Example output

      1. NAMESPACE NAME READY STATUS RESTARTS AGE
      2. openshift-apiserver-operator openshift-apiserver-operator-85cb746d55-zqhs8 1/1 Running 1 9m
      3. openshift-apiserver apiserver-67b9g 1/1 Running 0 3m
      4. openshift-apiserver apiserver-ljcmx 1/1 Running 0 1m
      5. openshift-apiserver apiserver-z25h4 1/1 Running 0 2m
      6. openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8 1/1 Running 0 5m
      7. ...
    2. View the logs for a pod that is listed in the output of the previous command by using the following command:

      1. $ oc logs <pod_name> -n <namespace> (1)
      1Specify the pod name and namespace, as shown in the output of the previous command.

      If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

Additional resources

Next steps