Introduction to kpack a Kubernetes Native Container Build Service

1-kpack-introduction.md

Prerequisites

• Docker (https://docs.docker.com/install/)
• kubectl (https://kubernetes.io/docs/tasks/tools/install-kubectl/)
• An image registry like Docker Hub (https://hub.docker.com/)

(Optional) Install local Kubernetes cluster

With kind tool (https://github.com/kubernetes-sigs/kind)

1. Install kind with go 1.11+ or see https://github.com/kubernetes-sigs/kind for alternatives

GO111MODULE="on" go get sigs.k8s.io/kind@v0.7.0

2. Create cluster

kind create cluster

3. Check current context

kubectl config current-context

Alternatives

• https://github.com/kubernetes/minikube
• https://github.com/ubuntu/microk8s

Install kpack (https://github.com/pivotal/kpack)

1. Download kpack release from Github, see https://github.com/pivotal/kpack/releases for the most recent release

kubectl apply -f https://github.com/pivotal/kpack/releases/download/v0.0.8/release-0.0.8.yaml

2. Ensure that the kpack controller has a status of "Running"

kubectl get pods --namespace kpack --watch

3. Check the logs to confirm the kpack controller started without error

kubectl -n kpack logs deployment/kpack-controller -f

4. Create a cluster-builder.yaml file based on the 2-cluster-builder.yaml file below for a ClusterBuilder resource and apply

kubectl apply -f cluster-builder.yaml

5. Ensure that kpack has processed the builder

kubectl get clusterbuilder default-builder -o yaml

Using kpack

1. Create a secret.yaml file with your push credentials for the docker registry based on the 3-secret.yaml file below and apply

kubectl apply -f secret.yaml

2. Create a service-account.yaml file that references the created registry secret based on the 4-service-account.yaml file below and apply

kubectl apply -f service-account.yaml

3. Fork the sample repository https://github.com/buildpack/sample-java-app to test the automatic rebuild functionality

4. Create a kpack image configuration file (image.yaml) with your forked repository based on the 5-image.yaml file below and apply

kubectl apply -f image.yaml

5. Download the kpack log untility (https://github.com/pivotal/kpack/blob/master/docs/logs.md) and tail logs from all builds for an image:

./logs -image java-sample-image

6. Push any update to the forked sample app repository. kpack should recognize the update and automatically rebuild your image.

You can see by viewing the logs(step #5) or by running

kubectl get builds

7. Run the latest image of the app locally with docker

docker run -p 8080:8080 index.docker.io/<docker-registry-username>/kpack-sample-java-app

8. Open localhost:8080 in your favorite browser

Destroy the cluster

kind delete cluster

2-cluster-builder.yaml

apiVersion: build.pivotal.io/v1alpha1
kind: ClusterBuilder
metadata:
  name: default-builder
spec:
  image: gcr.io/paketo-buildpacks/builder:full-cf
  updatePolicy: polling

3-secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: registry-credentials
  annotations:
    build.pivotal.io/docker: https://index.docker.io/v1/
type: kubernetes.io/basic-auth
stringData:
  username: <docker-registry-username>
  password: <docker-registry-password>

4-service-account.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
 name: service-account
secrets:
 - name: registry-credentials

5-image.yaml

apiVersion: build.pivotal.io/v1alpha1
kind: Image
metadata:
  name: java-sample-image
spec:
  tag: <docker-registry-username>/kpack-sample-java-app
  serviceAccount: service-account
  builder:
    name: default-builder
    kind: ClusterBuilder
  source:
    git:
      url: https://github.com/<github-username>/sample-java-app
      revision: master