Sample Docker App for Knative

Requirements

For the deployment and inspection of the Knative application discussed here, we are using the following tools:

• kubectl: The Kubernetes command-line tool for interacting with a Kubernetes deployment.
• ytt - YAML Templating Tool is the structure aware templating tool that @cppforlife and I developed for better templating of YAML configuration.
• kapp - Kubernetes Application Manager is the Kubernetes workflow management tool released by @cppforlife that consumes the generated output from ytt.
• IBM Kubernetes Service (IKS): the demo uses a Kubernetes cluster on IBM Cloud to launch and run the sample application. Some of the adjustments to the deployment process are specific to IKS.

The combination of ytt and kapp can be an alternative to a HELM chart+workflow management. While this project is pretty small for the purpose of the tool, it can be a good starting point.

Build the app

Build locally:

Run the following:

$ VERSION=<app-version> # this should be v1 or v2
$ ./hack/build.sh $VERSION 

Build the Docker image to push to a registry:

The Dockerfile builds the go app and puts it in the local registry. You can then upload it to dockerhub or your registry of choice.

$ REPO=<your-docker-registry>
$ VERSION=<app-version> # this should be v1 or v2
$ ./hack/dockerize.sh ${REPO} ${VERSION}
$ docker push ${REPO}:${VERSION}

Sample app + Knative

This application is meant to serve as a sample to demonstrate how Knative can be used as a serverless platform, how to apply revisions to a Knative serverless app, and how to achieve blue-green deployment and HPA. For the details of going through the tutorial, follow this tutorial document.