This example demonstrates how to build images with Knative build, starting from source stored in a GitHub repository.
Two variations are offered, one with a plain Knative Build, the other using a BuildTemplate.
First, you need to have Knative installed.
Please refer to the installation instructions for the options you have for installing Knative build
Both examples require a registry to push the created image into. For the simplicities sake, we install an insecure and unprotected registry directly into the current namespace.
kubectl create -f registry.ymlThis registry is only available within from the current namespace as registry.
Of course, feel free to adapt the examples below to use another registry which is more accessible than that.
To start a simple build with the Jib Maven Plugin you create the build with
kubectl create -f build-with-jib.ymlAs always, you might want to have a look into the descriptor, it contains some useful comments.
To monitor the build check the pods:
kubectl get pods
NAME READY STATUS RESTARTS AGE
random-generator-with-jib-pod-b68481 0/1 Init:1/3 0 7s
registry-59df4ddcdc-jhkdg 1/1 Running 0 42sand the logs
kubectl logs random-generator-with-jib-pod-b68481 -c build-step-build-and-push
[INFO] Scanning for projects...
Downloading: https://repo.maven.apache.org/maven2/....
....
[INFO]
[INFO] Containerizing application to registry:80/k8spatterns/random-generator...
[WARNING] Base image 'gcr.io/distroless/java' does not use a specific image digest - build may not be reproducible
[INFO] Retrieving registry credentials for registry:80...
[INFO] Getting base image gcr.io/distroless/java...
[INFO] Building dependencies layer...
[INFO] Building resources layer...
[INFO] Building classes layer...
[INFO]
[INFO] Container entrypoint set to [java, -cp, /app/resources:/app/classes:/app/libs/*, io.k8spatterns.examples.RandomGeneratorApplication]
[INFO]
[INFO] Built and pushed image as registry:80/k8spatterns/random-generator
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 24.203 s
[INFO] Finished at: 2019-01-22T11:24:16Z
[INFO] Final Memory: 39M/403M
[INFO] ------------------------------------------------------------------------In order to deploy see this application, see below.
As alternative you can build the application with a BuildTemplate.
First, install the template:
kubectl create -f maven-kaniko-buildtemplate.ymlYou can verify the template with
kubectl get buildtemplate
NAME AGE
maven-kaniko 7sNow start the build which uses this template:
kubectl create -f build-with-template.ymlYou can watch the progress of the build with
kubectl get pods
NAME READY STATUS RESTARTS AGE
random-generator-with-template-pod-0ae221 0/1 Completed 0 1m
kubectl logs random-generator-with-template-pod-0ae221 -c build-step-maven-build
.....
kubectl logs random-generator-with-template-pod-0ae221 -c build-step-image-build-and-push
.....When you have build the random-generator with one of the methods above, you can deploy it easily.
Unfortunately, for picking up images, Kubernetes (or at least Minikube) doesn’t support service DNS lookups in the image: field of a container specification.
So we need to insert the IP adress directly which you can do while deploying, like in:
cat random-generator-deploy.yml | \
sed -e "s/registry:80/$(kubectl get svc registry -o jsonpath={.spec.clusterIP}):80/" | \
kubectl create -f -This will also install an Ingress object which allows you access the service easily from outside the cluster.
If you are testing with Minikube, you should be sure that you have the Ingress addon enabled with minikube addons enable ingress before deploying the application.
On Minikube you then access the service with
curl -sL http://random-service.$(minikube ip).nip.io | jq .