OpenWhisk Actions on Managed Knative on IBM Standard Kubernetes Cluster

Doug Davis announced managed Knative on IBM Cloud Kubernetes services in February 2019. He has a blog post (Introducing Managed Knative on IBM Cloud Kubernetes Service) explaining how to enable managed Knative add-on in your Kuberentes cluster. And recently OpenWhisk community started prototyping OpenWhisk runtimes (specifically NodeJS) so that OpenWhisk actions can be deployed/invoked on Knative. We have a blog post (How to run OpenWhisk Actions on Knative?) demonstrating how-to on Docker for Desktop and minikube. Let’s experiment with IBM Kubernetes service and see how it differs from other enviornments.

Pre-requisites:

• IBM Standard Kubernetes Cluster with version 1.12.7 in Single Zone/Multi Zone with a flavor of 4 Cores 16GB RAM and 3 Worker Nodes. Feel free to go and grab 🥘 while you create your standard cluster 😄.
• IBM Cloud CLI to download the kubeconfig files for your cluster using:

ibmcloud ks cluster-config <cluster-name>

• kubectl configured to access IBM Kubernetes Cluster, verify:

kubectl cluster-info

• Enable Knative add-on (with some ☕️):

ibmcloud ks cluster-addon-enable knative <cluster-name>

• Verify that all pods are Running under istio-system, knative-build, knative-serving, knative-eventing, and knative-monitoring.

kubectl get pods --all-namespaces
NAMESPACE            NAME                                            READY   STATUS              RESTARTS   AGE
istio-system         cluster-local-gateway-6d8585d55d-jmmwn          1/1     Running             0          79s
...
knative-build        build-controller-865d99747c-lj9sh               1/1     Running             0          109s
...
knative-eventing     eventing-controller-64bf9bbf79-ccq5p            2/2     Running             0          79s
...
knative-monitoring   elasticsearch-logging-0                         1/1     Running             0          108s
...
knative-serving      activator-58fb6bdff4-5tsjh                      0/2     PodInitializing     0          78s
...
knative-sources      controller-manager-0                            1/1     Running             0          106s

Now, let’s follow the six steps process of building and serving OpenWhisk actions on Knative:

Build and Serve OpenWhisk Runtime on Knative

Step 1: Register Secrets for Your Container Registry on Knative

Knative needs access to your container registry in order to push locally built container image. I am using Docker Hub here but you can use any registry of your choice by changing the registry name under annotation.

Save this file as docker-secret.yaml after replacing DOCKERHUB_USERNAME_BASE64_ENCODED and DOCKERHUB_PASSWORD_BASE64_ENCODEDwith your Docker Hub username/password.

docker-secret.yaml.tmpl

Apply the secret resource manifest for Docker Hub:

$ kubectl apply -f docker-secret.yaml
secret/dockerhub-user-pass created

Verify secret exists:

$ kubectl get secret dockerhub-user-pass
NAME                    TYPE                                  DATA      AGE
dockerhub-user-pass     kubernetes.io/basic-auth              2       21s

Step 2: Create Service Account for our Knative Builds

Create a service account to link the build process with the registry secret created in Step 1 so that Knative build system can push container images to the registry using these credentials.

service-account.yaml

$ kubectl apply -f service-account.yaml
serviceaccount/openwhisk-runtime-builder created

Verify the service account exists:

$ kubectl get serviceaccount/openwhisk-runtime-builder
NAME                        SECRETS   AGE
openwhisk-runtime-builder   2         3m46s

Step 3: Install the Build Template for the NodeJS Runtime

Deploy OpenWhisk Build Template:

$ kubectl apply -f https://raw.githubusercontent.com/apache/incubator-openwhisk-runtime-nodejs/master/core/nodejsActionBase/buildtemplate.yaml
buildtemplate.build.knative.dev/openwhisk-nodejs-runtime created

Verify the Build Template exists:

$ kubectl get buildtemplate openwhisk-nodejs-runtime
NAME                       AGE
openwhisk-nodejs-runtime   2m

Step 4: Deploy NodeJS Runtime with Hello World Action Code

Configure the build file to point to your Docker Hub repo by replacing DOCKER_USERNAME with your username.

build.yaml

Deploy NodeJS runtime with action code:

$ kubectl apply -f build.yaml
build.build.knative.dev/nodejs-10-helloworld-with-params created

Verify the build pod exists:

$ kubectl get build.build.knative.dev/nodejs-10-helloworld-with-params
NAME                              SUCCEEDED   REASON   STARTTIME   COMPLETIONTIME
nodejs-10-helloworld-with-params   True                 8m

Step 5: Serve NodeJS Runtime as a Knative Service

Now that we have built the OpenWhisk NodeJS runtime image with the helloworld function baked into it, we can deploy that image as a Knative Service.

Configure the service template to point to the Docker Hub repo where the OpenWhisk runtime (built in step 4) will be pulled from. Replace ${DOCKER_USERNAME} and create service.yaml:

service.yaml

Deploy the runtime:

$ kubectl apply -f service.yaml
service.serving.knative.dev/nodejs-helloworld-with-params created

Step 6: Run Hello World Action

This is where it differs in the way we invoke the Knative service on IBM Kubernetes vs Docker for Desktop/minikube using JSON payload:

params.json

kubectl get ksvc nodejs-helloworld-with-params
NAME                            DOMAIN                                                                                  LATESTCREATED                         LATESTREADY                           READY   REASON
nodejs-helloworld-with-params   nodejs-helloworld-with-params.default.<cluster-name>.<region>.containers.appdomain.cloud   nodejs-helloworld-with-params-f2w4p   nodejs-helloworld-with-params-f2w4p   True
curl nodejs-helloworld-with-params.default.<cluster-name>.<region>.containers.appdomain.cloud -H "Content-Type: application/json" -d '@params.json'
{"payload":"Hello Jill from OK!"}

Hooray! 💃 We have our hello world action running on Knative on IBM Kubernetes.

Note that I was hitting memory limitation in installing Knative on free IBM Kubernetes cluster.

Enjoy! 👊