Configure IP autodetection

Configure IP autodetection

Big picture

Configure IP autodetection for Calico nodes to ensure the correct IP address is used for routing.

Value

When you install Calico on a node, an IP address and subnet is automatically detected. Calico provides several ways to configure IP/subnet autodetection, and supports configuring specific IPs for:

Hosts with multiple external interfaces
Host interfaces with multiple IP addresses
Changes to cross subnet packet encapsulation
Changes to host IP address

Features

This how-to guide uses the following Calico features:

Node resource

Concepts

Autodetecting node IP address and subnet

For internode routing, each Calico node must be configured with an IPv4 address and/or an IPv6 address. When you install Calico on a node, a node resource is automatically created using routing information that is detected from the host. For some deployments, you may want to update autodetection to ensure nodes get the correct IP address.

Sample default node resource after installation

apiVersion: projectcalico.org/v3
kind: Node
metadata:
  name: node-hostname
spec:
  bgp:
    asNumber: 64512
    ipv4Address: 10.244.0.1/24
    ipv6Address: 2000:db8:85a3::8a2e:370:7335/120
    ipv4IPIPTunnelAddr: 192.168.0.1

Autodetection methods

By default, Calico uses the first-found method; the first valid IP address on the first interface (excluding local interfaces such as the docker bridge). However, you can change the default method to any of the following:

Address assigned to Kubernetes node (kubernetes-internal-ip)
Address used by the node to reach a particular IP or domain (can-reach)
Regex to include matching interfaces (interface)
Regex to exclude matching interfaces (skip-interface)
A list of IP ranges in CIDR format to determine valid IP addresses on the node to choose from (cidrs)

For more details on autodetection methods, see node configuration reference.

How to

Change the autodetection method
Manually configure IP address and subnet for a node

Change the autodetection method

Operator
Manifest

As noted previously, the default autodetection method is first valid interface found (first-found). To use a different autodetection method, edit the default Installation custom resource, specifying the method. Below are examples of the supported autodetection methods:

note

To configure the default autodetection method for IPv6 for any of the below methods, use the field nodeAddressAutodetectionV6.

Kubernetes Node IP

Calico will select the first internal IP address listed in the Kubernetes node’s Status.Addresses field.

kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
  name: default
spec:
  calicoNetwork:
    nodeAddressAutodetectionV4:
      kubernetes: NodeInternalIP

Source address used to reach an IP or domain name

Calico will choose the IP address that is used to reach the given “can reach” IP address or domain. For example:

kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
  name: default
spec:
  calicoNetwork:
    nodeAddressAutodetectionV4:
      canReach: 8.8.8.8

Including matching interfaces

Calico will choose an address on each node from an interface that matches the given regex. For example:

kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
  name: default
spec:
  calicoNetwork:
    nodeAddressAutodetectionV4:
      interface: eth.*

Excluding matching interfaces

Calico will choose an address on each node from an interface that does not match the given regex. For example:

kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
  name: default
spec:
  calicoNetwork:
    nodeAddressAutodetectionV4:
      skipInterface: eth.*

Including CIDRs

Calico will select any IP address from the node that falls within the given CIDRs. For example:

kind: Installation
apiVersion: operator.tigera.io/v1
metadata:
  name: default
spec:
  calicoNetwork:
    nodeAddressAutodetectionV4:
      cidrs:
        - '192.168.200.0/24'

As noted previously, the default autodetection method is first valid interface found (first-found). To use a different autodetection method, use the following kubectl set env command, specifying the method:

IPv4

kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=<autodetection-method>

IPv6

kubectl set env daemonset/calico-node -n kube-system IP6_AUTODETECTION_METHOD=<autodetection-method>

Where autodetection methods are based on:

Kubernetes Node IP

Calico will select the first internal IP address listed in the Kubernetes node’s Status.Addresses field.
```
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=kubernetes-internal-ip
```
Source address used to reach an IP or domain name

Calico will choose the IP address that is used to reach the given “can reach” IP address or domain. For example:
```
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=can-reach=www.google.com
```
Including matching interfaces

Calico will choose an address on each node from an interface that matches the given regex. For example:
```
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=interface=eth.*
```
Excluding matching interfaces

Calico will choose an address on each node from an interface that does not match the given regex. For example:
```
kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=skip-interface=eth.*
```

Including CIDRs

Calico will select any IP address from the node that falls within the given CIDRs. For example:

kubectl set env daemonset/calico-node -n kube-system IP_AUTODETECTION_METHOD=cidr=192.168.200.0/24,172.15.0.0/24

Manually configure IP address and subnet for a node

In the following scenarios, you may want to configure a specific IP and subnet:

Hosts with multiple external interfaces
Host interfaces with multiple IP addresses
Changes to cross subnet packet encapsulation
Changes to host IP address
Operator
Manifest

You can configure specific IP address and subnet for a node by disabling IP autodetection and then updating the Node resource.

Disable autodetection

To disable autodetection method, update the proper NodeAddressAutodetection field in the Installation resource:

apiVersion: operator.tigera.io/v1
kind: Installation
metadata:
  name: default
spec:
  calicoNetwork:
    nodeAddressAutodetectionV4: {}
    nodeAddressAutodetectionV6: {}

Configure IP and subnet using node resource

You can configure the IP address and subnet on a Node resource.

Use calicoctl patch to update the current node configuration. For example:

calicoctl patch node kind-control-plane \
  --patch='{"spec":{"bgp": {"ipv4Address": "10.0.2.10/24", "ipv6Address": "fd80:24e2:f998:72d6::/120"}}}'

You can configure specific IP address and subnet for a node using environment variables or by updating the Node resource. Because you can configure IP address and subnet using either environment variables or node resource, the following table describes how values are synchronized.

If this environment variable…	Is…	Then…
IP/IP6	Explicitly set	The specified values are used, and the Node resource is updated.
	Set to autodetect	The requested method is used (first-found, can-reach, interface, skip-interface, kubernetes-internal-ip), and the Node resource is updated.
	Not set, but Node resource has IP/IP6 values	Node resource value is used.
IP	Not set, and there is no IP value in Node resource	Autodetects an IPv4 address and subnet, and updates Node resource.
IP6	Not set, and there is a no IP6 value in Node resource	No IP6 routing is performed on the node.

Configure IP and subnet using environment variables

To configure IP and subnet values using environment variables, use a kubectl set env command. For example:

kubectl set env daemonset/calico-node -n kube-system IP=10.0.2.10/24 IP6=fd80:24e2:f998:72d6::/120

note

If the subnet is omitted, the defaults are: /32 (IPv4) and /128 (IPv6). We recommend that you include the subnet information for clarity when specifying IP addresses.

Configure IP and subnet using node resource

You can also configure the IP address and subnet on a Node resource.

note

When configuring the IP address on a Node resource, you may want to disable IP address options or environment variables on the node. IP options on the container take precedence, and will overwrite the values you configure on the node resource.

Use calicoctl patch to update the current node configuration. For example:

calicoctl patch node kind-control-plane \
  --patch='{"spec":{"bgp": {"ipv4Address": "10.0.2.10/24", "ipv6Address": "fd80:24e2:f998:72d6::/120"}}}'

Additional resources

For details on autodetection methods, see the node configuration reference.
For calicoctl environment variables, see Configuring calico/node
Node resource
Reference documentation for calicoctl patch