Deploying an Express Handler to Knative

• Installing Knative (for Kubernetes in Docker for Mac)
• Installing the Express Action build template
• Build and deploy your handler
• Testing your Handler

Installing Knative

1. Ramp up memory usage of Kubernetes

• Click on the Docker logo in the toolbar and select Preferences...
• Move the Memory slider to at least 6.0GiB
• Click Apply & Restart

2. Install Istio using NodePort rather than LoadBalancer (there is no LoadBalancer in the embedded Kubernetes in Docker for Mac) and reducing the memory usage of Pilot from 2048Mi to 512Mi:

curl -L http://storage.googleapis.com/knative-releases/serving/latest/istio.yaml | sed 's/LoadBalancer/NodePort/' | sed 's/2048/512/' | kubectl apply -f -

3. Enable Istio injection:

kubectl label namespace default istio-injection=enabled

4. Wait for Istio to come up:

$ kubectl get pods --namespace=istio-system

5. Install Knative*-Lite* with NodePort rather than LoadBalancer:

curl -L http://storage.googleapis.com/knative-releases/serving/latest/release-lite.yaml | sed 's/LoadBalancer/NodePort/' | kubectl apply -f -

6. Wait for Knative Serving and Knative Build to come up:

kubectl get pods --namespace=knative-serving
kubectl get pods --namespace=knative-build

Installing the Express Action build template

1. Create the following as express-action.yaml for the “express-action” build template:

apiVersion: build.knative.dev/v1alpha1
kind: BuildTemplate
metadata:
  name: express-action 
spec:
  parameters:
  - name: IMAGE
    description: The name of the image to push
  - name: DOCKERFILE
    description: Path to the Dockerfile to build.
    default: /workspace/Dockerfile

  steps:
  - name: get-dockerfile
    image: ubuntu
    imagePullPolicy: IfNotPresent
    command: ["/bin/bash"]
    args: ["-c", "apt-get update;apt-get install -y wget;wget https://raw.githubusercontent.com/seabaylea/expressjs-action-build/master/Dockerfile-build -O /workspace/Dockerfile-build;"]
  - name: build-and-push 
    image: gcr.io/kaniko-project/executor
    imagePullPolicy: IfNotPresent
    args:
    - --dockerfile=/workspace/Dockerfile-build
    - --destination=${IMAGE}

2. Install the template:

kubectl apply -f express-action.yaml

Build and deploy your handler

1. Create the following as my-express-action.yaml your applications build definition:

apiVersion: serving.knative.dev/v1alpha1
kind: Service
metadata:
  name: my-express-action 
  namespace: default
spec:
  runLatest:
    configuration:
      build:
        apiVersion: build.knative.dev/v1alpha1
        kind: Build
        spec:
          serviceAccountName: build-bot
          source:
            git:
              url: https://github.com/seabaylea/action.git
              revision: master
          template:
            name: express-action 
            arguments:
              - name: IMAGE
                value: docker.io/seabaylea/my-express-action:latest
      revisionTemplate:
        spec:
          container:
            image: docker.io/seabaylea/my-express-action:latest
            imagePullPolicy: IfNotPresent

2. Build and install your application:

kubectl apply -f my-express-action.yaml

3. Check the deployments and make sure its listed

kubectl get deployments

Should respond with:

NAME                              DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
my-express-action-00001-deployment   1         1         1            1           1m

4. Get the deployed service

kubectl get service my-express-action

Should respond with:

NAME             TYPE           CLUSTER-IP   EXTERNAL-IP                                             PORT(S)   AGE
my-express-action   ExternalName   <none>       knative-ingressgateway.istio-system.svc.cluster.local   <none>    1m

Testing your Handler

1. Find the NodePort for your application:

kubectl get svc knative-ingressgateway -n istio-system

Should respond with:

NAME                     TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)                                                                                                                   AGE
knative-ingressgateway   NodePort   10.111.249.41   <none>        80:32380/TCP,443:32390/TCP,31400:32400/TCP,15011:30535/TCP,8060:30364/TCP,853:32032/TCP,15030:32150/TCP,15031:30732/TCP   1h

Grab the port mapped to 80, in this case 32380.

2. Access the service using cURL:

curl -v -H "Host: my-express-action.default.example.com" http://127.0.0.1:32380

The structure for Host is {service-name}.{namespace}.example.com

3. Check that you get the expected response:

* Rebuilt URL to: http://127.0.0.1:32380/
*   Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 32380 (#0)
> GET / HTTP/1.1
> Host: my-express-action.default.example.com
> User-Agent: curl/7.61.1
> Accept: */*
> 
< HTTP/1.1 200 OK
< content-length: 20
< content-type: text/html; charset=utf-8
< date: Thu, 06 Dec 2018 11:46:48 GMT
< etag: W/"14-VKC9Q8ZTduiYvUDeKbM7TN/QrTA"
< server: envoy
< x-envoy-upstream-service-time: 8244
< x-powered-by: Express
< 
* Connection #0 to host 127.0.0.1 left intact
Hello Knative World!