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 stable @ v0.9 provides an abstraction for stateless request-based scale-to-zero services.
• Eventing stable @ v0.16 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 v0.20.0 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

The following commands install the Knative Serving component.

1. Install the Custom Resource Definitions (aka CRDs):

   kubectl apply --filename https://github.com/knative/serving/releases/download/v0.20.0/serving-crds.yaml
   

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

   kubectl apply --filename https://github.com/knative/serving/releases/download/v0.20.0/serving-core.yaml
   

3. Pick a networking layer (alphabetical):

   • Ambassador
   • Contour
   • Gloo
   • Istio
   • Kong
   • Kourier
   FEATURE STATE: alpha @ Knative v0.8

   The following commands install Ambassador and enable its Knative integration.

   1. Create a namespace to install Ambassador in:

      kubectl create namespace ambassador
      

   2. 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
      

   3. Give Ambassador the required permissions:

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

   4. Enable Knative support in Ambassador:

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

   5. 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"}}'
      

   6. Fetch the External IP or CNAME:

      kubectl --namespace ambassador get service ambassador
      

      Save this for configuring DNS below.

   FEATURE STATE: stable @ Knative v0.18

   The following commands install Contour and enable its Knative integration.

   1. Install a properly configured Contour:

      kubectl apply --filename https://github.com/knative/net-contour/releases/download/v0.20.0/contour.yaml
      

   2. Install the Knative Contour controller:

      kubectl apply --filename https://github.com/knative/net-contour/releases/download/v0.20.0/net-contour.yaml
      

   3. 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"}}'
      

   4. Fetch the External IP or CNAME:

      kubectl --namespace contour-external get service envoy
      

      Save this for configuring DNS below.

   FEATURE STATE: alpha @ Knative v0.8

   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.

   1. 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.

   2. Install Gloo and the Knative integration:

      glooctl install knative --install-knative=false
      

   3. Fetch the External IP or CNAME:

      glooctl proxy url --name knative-external-proxy
      

      Save this for configuring DNS below.

   FEATURE STATE: stable @ Knative v0.9

   The following commands install Istio and enable its Knative integration.

   1. Installing Istio for Knative

   2. Install the Knative Istio controller:

      kubectl apply --filename https://github.com/knative/net-istio/releases/download/v0.20.0/release.yaml
      

   3. Fetch the External IP or CNAME:

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

      Save this for configuring DNS below.

   FEATURE STATE: @ Knative v0.13

   The following commands install Kong and enable its Knative integration.

   1. 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
      

   2. To configure Knative Serving to use Kong by default:

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

   3. Fetch the External IP or CNAME:

      kubectl --namespace kong get service kong-proxy
      

      Save this for configuring DNS below.

   FEATURE STATE: beta @ Knative v0.17

   The following commands install Kourier and enable its Knative integration.

   1. Install the Knative Kourier controller:

      kubectl apply --filename https://github.com/knative/net-kourier/releases/download/v0.20.0/kourier.yaml
      

   2. 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"}}'
      

   3. Fetch the External IP or CNAME:

      kubectl --namespace kourier-system get service kourier
      

      Save this for configuring DNS below.

4. Configure DNS

   • Magic DNS (xip.io)
   • Real DNS
   • Temporary 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/v0.20.0/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.

5. 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!

Optional Serving extensions

• HPA autoscaling
• TLS with cert-manager
• TLS via HTTP01
• TLS wildcard support
• DomainMapping CRD

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.20.0/serving-hpa.yaml

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.20.0/serving-nscert.yaml

kubectl apply --filename https://github.com/knative/serving/releases/download/v0.20.0/serving-domainmapping-crds.yaml
kubectl wait --for=condition=Established --all crd
kubectl apply --filename https://github.com/knative/serving/releases/download/v0.20.0/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

The following commands install the Knative Eventing component.

1. Install the Custom Resource Definitions (aka CRDs):

   kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.20.0/eventing-crds.yaml
   

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

   kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.20.0/eventing-core.yaml
   

3. Install a default Channel (messaging) layer (alphabetical).

   • Apache Kafka Channel
   • Google Cloud Pub/Sub Channel
   • In-Memory (standalone)
   • NATS Channel

   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/v0.20.0/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/v0.20.0/cloud-run-events.yaml
      

   To learn more about the Google Cloud Pub/Sub Channel, try our sample

   FEATURE STATE: stable @ Knative v0.16

   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/v0.20.0/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/v0.20.0/300-natss-channel.yaml
      

4. Install a Broker (eventing) layer:

   • Apache Kafka Broker
   • MT-Channel-based
   FEATURE STATE: alpha @ Knative v0.17

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

   1. Install the Kafka controller by entering the following command:

      kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka-broker/releases/download/v0.20.0/eventing-kafka-controller.yaml
      

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

      kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka-broker/releases/download/v0.20.0/eventing-kafka-broker.yaml
      

   For more information, see the Kafka Broker documentation.

   FEATURE STATE: stable @ Knative v0.16

   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/v0.20.0/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.

5. 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

kubectl apply --filename https://github.com/knative/eventing/releases/download/v0.20.0/eventing-sugar-controller.yaml

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

kubectl apply --filename https://github.com/knative-sandbox/eventing-github/releases/download/v0.20.0/github.yaml

kubectl apply --filename https://github.com/knative-sandbox/eventing-github/releases/download/v0.20.0/mt-github.yaml

kubectl apply --filename https://github.com/knative-sandbox/eventing-camel/releases/download/v0.20.0/camel.yaml

kubectl apply --filename https://github.com/knative-sandbox/eventing-kafka/releases/download/v0.20.0/source.yaml

# This installs both the Sources and the Channel.
kubectl apply --filename https://github.com/google/knative-gcp/releases/download/v0.20.0/cloud-run-events.yaml

kubectl apply --filename https://github.com/knative-sandbox/eventing-couchdb/releases/download/v0.20.0/couchdb.yaml

kubectl apply --filename https://github.com/vmware-tanzu/sources-for-knative/releases/download/v0.20.0/release.yaml

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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