Overview

Kustomization of https://github.com/fabiand/instanceTypes/

This example does two things:

1. Use kustomize to create custom variants
2. Use Argo CD application to deploy these files to a cluster

This repository is very simple. There is no magic outside of this repository besides Argo CD and Kustomize.

Kustomize

overlays/staging/kustomization.yaml shows what kind of modifications are done to the stock instanceTypes. The same is true for the production overlay.

Application

staging.app.argocd.yaml defines how Argo CD should consume this repo, and sync it to the cluster. Argo CD has built-in support for kustomize, therefore nothing else is needed.

Local build

Locally the custom instanceTypes can be produced by running:

$ kubectl kustomize

Deploy to cluster with Argo on OpenShift

Note The yaml below assumes the namespace fabiand Adjust the yaml if you want to deploy the custom ITs elsewhere

The file staging.app.argocd.yaml is an Argo Application definition. Submitting this file to an Argo enabled cluster will automate the whole deplpoyment.

1. Install OpenShift GitOps Operator and

1. Install OpenShift GitOps using the regular OperatorHub workflow
2. Enable Argo in a namespace by creating an ArgoCD object (Use the Operator UI to do this)

2. Deploy the /staging instanceTypes/ "App"

# Deploy the small app:
$ oc apply -n fabiand -f staging.app.argocd.yaml
application.argoproj.io/it-staging created

That's it. Argo CD will pick up the new app, and start deploying it immediately.

3. Verify deployment of custom instanceTypes

Within seconds, argo should have reconciled the app. This means the repo was cloned, kustomize applied, and resulting artifacts deployed to the cluster:

$ oc get virtualmachineinstancetypes -n fabiand
NAME              AGE
staging-c1.2xlarge    52s
staging-c1.4xlarge    52s
staging-c1.large      52s
staging-c1.medium     52s
staging-cx1.2xlarge   52s
staging-cx1.4xlarge   52s
staging-cx1.large     52s
staging-cx1.medium    52s
…

4. Optional: View Argo CD dashboard

Optionally you can log into the Argo CD dashbaord in oreder to check what's going on:

# Get the Argo admin password:
$ oc get -n fabiand secret argocd-cluster -o jsonpath='{.data.admin\.password}' | base64 -d
Tc7E9v1neFp8BAOZG…

# Get the Argo dashboard path with:
$ oc get -n fabiand argocd argocd -o jsonpath="{.status.host}"
argocd-server-fabiand.apps.example.com

Now log into the Argo CD dashboard using admin and the password from the last step.

5. Optional: Comparing overlays

It's helpful to compare how overlays / environments differ, you can do this by:

$ kubectl kustomize overlays/staging > staging.yaml
$ kubectl kustomize overlays/production > production.yaml
$ vimdiff staging.yaml production.yaml

References

Relevant links

• Argo CD
  • https://redhat-scholars.github.io/argocd-tutorial/argocd-tutorial/index.html
• Kustomize
  • https://kubernetes.io/docs/tasks/manage-kubernetes-objects/kustomization/
  • https://github.com/kubernetes-sigs/kustomize
• GitOps patterns
  • https://developers.redhat.com/articles/2022/07/20/git-workflows-best-practices-gitops-deployments
  • https://codefresh.io/blog/stop-using-branches-deploying-different-gitops-environments/
  • https://codefresh.io/blog/how-to-model-your-gitops-environments-and-promote-releases-between-them/
  • https://codefresh.io/blog/applied-gitops-with-kustomize/