Installing Knative

Installing Knative

This guide walks you through the installation of the latest version of Knative. Note if you are upgrading an existing installation, follow the instructions here.

Knative has two components, which can be installed and used independently or together. To help you pick and choose the pieces that are right for you, here is a brief description of each:

Serving provides an abstraction for stateless request-based scale-to-zero services.
Eventing provides abstractions to enable binding event sources (e.g. Github Webhooks, Kafka) and consumers (e.g. Kubernetes or Knative Services).

Before you begin

This guide assumes that you want to install an upstream Knative release on a Kubernetes cluster. A growing number of vendors have managed Knative offerings; see the Knative Offerings page for a full list.

Knative v0.21.0 requires a Kubernetes cluster v1.17 or newer, as well as a compatible kubectl. This guide assumes that you’ve already created a Kubernetes cluster, and that you are using bash in a Mac or Linux environment; some commands will need to be adjusted for use in a Windows environment.

Installing the Serving component

Install the Custom Resource Definitions (aka CRDs):

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-crds.yaml

Install the core components of Serving (see below for optional extensions):

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-core.yaml

Pick a networking layer (alphabetical):

Ambassador
Contour
Gloo
Istio
Kong
Kourier

The following commands install Ambassador and enable its Knative integration.

Create a namespace to install Ambassador in:
```
kubectl create namespace ambassador
```

Install Ambassador:

kubectl apply --namespace ambassador \
  --filename https://getambassador.io/yaml/ambassador/ambassador-crds.yaml \
  --filename https://getambassador.io/yaml/ambassador/ambassador-rbac.yaml \
  --filename https://getambassador.io/yaml/ambassador/ambassador-service.yaml

Give Ambassador the required permissions:

kubectl patch clusterrolebinding ambassador -p '{"subjects":[{"kind": "ServiceAccount", "name": "ambassador", "namespace": "ambassador"}]}'

Enable Knative support in Ambassador:

kubectl set env --namespace ambassador  deployments/ambassador AMBASSADOR_KNATIVE_SUPPORT=true

To configure Knative Serving to use Ambassador by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"ambassador.ingress.networking.knative.dev"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace ambassador get service ambassador
```
Save this for configuring DNS below.

The following commands install Contour and enable its Knative integration.

Install a properly configured Contour:

kubectl apply --filename https://github.com/knative/net-contour/releases/download/v0.21.0/contour.yaml

Install the Knative Contour controller:

kubectl apply --filename https://github.com/knative/net-contour/releases/download/v0.21.0/net-contour.yaml

To configure Knative Serving to use Contour by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"contour.ingress.networking.knative.dev"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace contour-external get service envoy
```
Save this for configuring DNS below.

For a detailed guide on Gloo integration, see Installing Gloo for Knative in the Gloo documentation.

The following commands install Gloo and enable its Knative integration.

Make sure glooctl is installed (version 1.3.x and higher recommended):
```
glooctl version
```
If it is not installed, you can install the latest version using:
```
curl -sL https://run.solo.io/gloo/install | sh
export PATH=$HOME/.gloo/bin:$PATH
```
Or following the Gloo CLI install instructions.

Install Gloo and the Knative integration:

glooctl install knative --install-knative=false

Fetch the External IP or CNAME:
```
glooctl proxy url --name knative-external-proxy
```
Save this for configuring DNS below.

The following commands install Istio and enable its Knative integration.

Install a properly configured Istio (Advanced installation)

kubectl apply --filename https://github.com/knative/net-istio/releases/download/v0.21.0/istio.yaml

Install the Knative Istio controller:

kubectl apply --filename https://github.com/knative/net-istio/releases/download/v0.21.0/net-istio.yaml

Fetch the External IP or CNAME:

kubectl --namespace istio-system get service istio-ingressgateway

Save this for configuring DNS below.

The following commands install Kong and enable its Knative integration.

Install Kong Ingress Controller:

kubectl apply --filename https://raw.githubusercontent.com/Kong/kubernetes-ingress-controller/0.9.x/deploy/single/all-in-one-dbless.yaml

To configure Knative Serving to use Kong by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"kong"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace kong get service kong-proxy
```
Save this for configuring DNS below.

The following commands install Kourier and enable its Knative integration.

Install the Knative Kourier controller:

kubectl apply --filename https://github.com/knative/net-kourier/releases/download/v0.21.0/kourier.yaml

To configure Knative Serving to use Kourier by default:

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress.class":"kourier.ingress.networking.knative.dev"}}'

Fetch the External IP or CNAME:
```
kubectl --namespace kourier-system get service kourier
```
Save this for configuring DNS below.

Configure DNS
We ship a simple Kubernetes Job called “default domain” that will (see caveats) configure Knative Serving to use xip.io as the default DNS suffix.
```
kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-default-domain.yaml
```
Caveat: This will only work if the cluster LoadBalancer service exposes an IPv4 address or hostname, so it will not work with IPv6 clusters or local setups like Minikube. For these, see “Real DNS” or “Temporary DNS”.

To configure DNS for Knative, take the External IP or CNAME from setting up networking, and configure it with your DNS provider as follows:
- If the networking layer produced an External IP address, then configure a wildcard A record for the domain:
```
# Here knative.example.com is the domain suffix for your cluster
*.knative.example.com == A 35.233.41.212
```
- If the networking layer produced a CNAME, then configure a CNAME record for the domain:
```
# Here knative.example.com is the domain suffix for your cluster
*.knative.example.com == CNAME a317a278525d111e89f272a164fd35fb-1510370581.eu-central-1.elb.amazonaws.com
```
Once your DNS provider has been configured, direct Knative to use that domain:
```
# Replace knative.example.com with your domain suffix
kubectl patch configmap/config-domain \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"knative.example.com":""}}'
```
If you are using curl to access the sample applications, or your own Knative app, and are unable to use the “Magic DNS (xip.io)” or “Real DNS” methods, there is a temporary approach. This is useful for those who wish to evaluate Knative without altering their DNS configuration, as per the “Real DNS” method, or cannot use the “Magic DNS” method due to using, for example, minikube locally or IPv6 clusters.

To access your application using curl using this method:
1. After starting your application, get the URL of your application:
```
kubectl get ksvc
```
  The output should be similar to:
```
NAME            URL                                        LATESTCREATED         LATESTREADY           READY   REASON
helloworld-go   http://helloworld-go.default.example.com   helloworld-go-vqjlf   helloworld-go-vqjlf   True
```
2. Instruct curl to connect to the External IP or CNAME defined by the networking layer in section 3 above, and use the -H "Host:" command-line option to specify the Knative application’s host name. For example, if the networking layer defines your External IP and port to be http://192.168.39.228:32198 and you wish to access the above helloworld-go application, use:
```
curl -H "Host: helloworld-go.default.example.com" http://192.168.39.228:32198
```
  In the case of the provided helloworld-go sample application, the output should, using the default configuration, be:
```
Hello Go Sample v1!
```
Refer to the “Real DNS” method for a permanent solution.
Monitor the Knative components until all of the components show a STATUS of Running or Completed:
```
kubectl get pods --namespace knative-serving
```

At this point, you have a basic installation of Knative Serving!

Knative also supports the use of the Kubernetes Horizontal Pod Autoscaler (HPA) for driving autoscaling decisions. The following command will install the components needed to support HPA-class autoscaling:

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-hpa.yaml

Knative supports automatically provisioning TLS certificates via cert-manager. The following commands will install the components needed to support the provisioning of TLS certificates via cert-manager.

First, install cert-manager version 0.12.0 or higher

Next, install the component that integrates Knative with cert-manager:

kubectl apply --filename https://github.com/knative/net-certmanager/releases/download/v0.21.0/release.yaml

Now configure Knative to automatically configure TLS certificates.

Knative supports automatically provisioning TLS certificates using Let’s Encrypt HTTP01 challenges. The following commands will install the components needed to support that.

First, install the net-http01 controller:

kubectl apply --filename https://github.com/knative/net-http01/releases/download/v0.21.0/release.yaml

Next, configure the certificate.class to use this certificate type.

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"certificate.class":"net-http01.certificate.networking.knative.dev"}}'

Lastly, enable auto-TLS.

kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"autoTLS":"Enabled"}}'

If you are using a Certificate implementation that supports provisioning wildcard certificates (e.g. cert-manager with a DNS01 issuer), then the most efficient way to provision certificates is with the namespace wildcard certificate controller. The following command will install the components needed to provision wildcard certificates in each namespace:

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-nscert.yaml

Note this will not work with HTTP01 either via cert-manager or the net-http01 options.

The DomainMapping CRD allows a user to map a Domain Name that they own to a specific Knative Service.

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-domainmapping-crds.yaml
kubectl wait --for=condition=Established --all crd
kubectl apply --filename https://github.com/knative/serving/releases/download/v0.21.0/serving-domainmapping.yaml

Getting started with Serving

Deploy your first app with the getting started with Knative app deployment guide. You can also find a number of samples for Knative Serving here.

Installing the Eventing component

Install the Custom Resource Definitions (aka CRDs):

kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.21.0/eventing-crds.yaml

Install the core components of Eventing (see below for optional extensions):

kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.21.0/eventing-core.yaml

Install a default Channel (messaging) layer (alphabetical).
1. First, Install Apache Kafka for Kubernetes
2. Then install the Apache Kafka Channel:
```
curl -L "https://github.com/knative-sandbox/eventing-kafka/releases/download/v0.21.0/channel-consolidated.yaml" \
 | sed 's/REPLACE_WITH_CLUSTER_URL/my-cluster-kafka-bootstrap.kafka:9092/' \
 | kubectl apply --filename -
```
To learn more about the Apache Kafka channel, try our sample
1. Install the Google Cloud Pub/Sub Channel:
```
# This installs both the Channel and the GCP Sources.
kubectl apply --filename https://github.com/google/knative-gcp/releases/download/v0.21.0/cloud-run-events.yaml
```
To learn more about the Google Cloud Pub/Sub Channel, try our sample

The following command installs an implementation of Channel that runs in-memory. This implementation is nice because it is simple and standalone, but it is unsuitable for production use cases.
```
kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.21.0/in-memory-channel.yaml
```
1. First, Install NATS Streaming for Kubernetes
2. Then install the NATS Streaming Channel:
```
kubectl apply --filename https://github.com/knative-sandbox/eventing-natss/releases/download/v0.21.0/300-natss-channel.yaml
```

Install a Broker (eventing) layer:

Apache Kafka Broker
MT-Channel-based

The following commands install the Apache Kafka broker, and run event routing in a system namespace, knative-eventing, by default.

Install the Kafka controller by entering the following command:

kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka-broker/releases/download/v0.21.0/eventing-kafka-controller.yaml

Install the Kafka Broker data plane by entering the following command:

kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka-broker/releases/download/v0.21.0/eventing-kafka-broker.yaml

For more information, see the Kafka Broker documentation.

The following command installs an implementation of Broker that utilizes Channels and runs event routing components in a System Namespace, providing a smaller and simpler installation.

kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.21.0/mt-channel-broker.yaml

To customize which broker channel implementation is used, update the following ConfigMap to specify which configurations are used for which namespaces:

apiVersion: v1
kind: ConfigMap
metadata:
  name: config-br-defaults
  namespace: knative-eventing
data:
  default-br-config: |
    # This is the cluster-wide default broker channel.
    clusterDefault:
      brokerClass: MTChannelBasedBroker
      apiVersion: v1
      kind: ConfigMap
      name: imc-channel
      namespace: knative-eventing
    # This allows you to specify different defaults per-namespace,
    # in this case the "some-namespace" namespace will use the Kafka
    # channel ConfigMap by default (only for example, you will need
    # to install kafka also to make use of this).
    namespaceDefaults:
      some-namespace:
        brokerClass: MTChannelBasedBroker
        apiVersion: v1
        kind: ConfigMap
        name: kafka-channel
        namespace: knative-eventing

The referenced imc-channel and kafka-channel example ConfigMaps would look like:

apiVersion: v1
kind: ConfigMap
metadata:
  name: imc-channel
  namespace: knative-eventing
data:
  channelTemplateSpec: |
    apiVersion: messaging.knative.dev/v1
    kind: InMemoryChannel
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: kafka-channel
  namespace: knative-eventing
data:
  channelTemplateSpec: |
    apiVersion: messaging.knative.dev/v1alpha1
    kind: KafkaChannel
    spec:
      numPartitions: 3
      replicationFactor: 1

In order to use the KafkaChannel make sure it is installed on the cluster as discussed above.

Monitor the Knative components until all of the components show a STATUS of Running:
```
kubectl get pods --namespace knative-eventing
```

At this point, you have a basic installation of Knative Eventing!

Optional Eventing extensions

Apache Kafka Sink
Sugar Controller
Github Source
Apache Camel-K Source
Apache Kafka Source
GCP Sources
Apache CouchDB Source
VMware Sources and Bindings

Install the Kafka controller:

kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka-broker/releases/download/v0.21.0/eventing-kafka-controller.yaml

Install the Kafka Sink data plane:

kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka-broker/releases/download/v0.21.0/eventing-kafka-sink.yaml

For more information, see the Kafka Sink documentation.

The following command installs the Eventing Sugar Controller:

kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.21.0/eventing-sugar-controller.yaml

The Knative Eventing Sugar Controller will react to special labels and annotations and produce Eventing resources. For example:

When a Namespace is labeled with eventing.knative.dev/injection=enabled, the controller will create a default broker in that namespace.
When a Trigger is annotated with eventing.knative.dev/injection=enabled, the controller will create a Broker named by that Trigger in the Trigger’s Namespace.

The following command enables the default Broker on a namespace (here default):

kubectl label namespace default eventing.knative.dev/injection=enabled

The following command installs the single-tenant Github source:

kubectl apply --filename https://github.com/knative-sandbox/eventing-github/releases/download/v0.21.0/github.yaml

The single-tenant GitHub source creates one Knative service per GitHub source.

The following command installs the multi-tenant GitHub source:

kubectl apply --filename https://github.com/knative-sandbox/eventing-github/releases/download/v0.21.0/mt-github.yaml

The multi-tenant GitHub source creates only one Knative service handling all GitHub sources in the cluster. This source does not support logging or tracing configuration yet.

To learn more about the Github source, try our sample

The following command installs the Apache Camel-K Source:

kubectl apply --filename https://github.com/knative-sandbox/eventing-camel/releases/download/v0.21.0/camel.yaml

To learn more about the Apache Camel-K source, try our sample

The following command installs the Apache Kafka Source:

kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka/releases/download/v0.21.0/source.yaml

To learn more about the Apache Kafka source, try our sample

The following command installs the GCP Sources:

# This installs both the Sources and the Channel.
kubectl apply --filename https://github.com/google/knative-gcp/releases/download/v0.21.0/cloud-run-events.yaml

To learn more about the Cloud Pub/Sub source, try our sample.

To learn more about the Cloud Storage source, try our sample.

To learn more about the Cloud Scheduler source, try our sample.

To learn more about the Cloud Audit Logs source, try our sample.

The following command installs the Apache CouchDB Source:

kubectl apply --filename https://github.com/knative-sandbox/eventing-couchdb/releases/download/v0.21.0/couchdb.yaml

To learn more about the Apache CouchDB source, read the documentation.

The following command installs the VMware Sources and Bindings:

kubectl apply --filename https://github.com/vmware-tanzu/sources-for-knative/releases/download/v0.21.0/release.yaml

To learn more about the VMware sources and bindings, try our samples.

Getting started with Eventing

You can find a number of samples for Knative Eventing here. A quick-start guide is available here.

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