schwannden / helm-and-kustomize

Studies the differences between helm and kustomize

Helm & Kustomization

This repository deploys a demo backend app in raw kubernetes object yaml files, using helm chart, and using kustomization. And discuss their differences. One can use this as a starting point to:

1. Learn helm chart.
2. Lean kustomization.
3. Learn the differences between them.

Requirement

1. k3d: we use this to provision a k8s cluster as playground.
2. just: our project command line interface (similar to make but much better).

Preparation

1. cd demo-backend
2. just build

Our backend service has an api /status, and can be built in demo-backend folder with just build. The api detect ENV's value and return different response accordingly.

• When ENV is dev or is missing, it returns
  • {"status":"ok", "ENV":"dev", "cpu":0.4, "memory_usage":2243194880}
• When ENV is not dev, it returns
  • {"status":"ok","ENV":"actual env value"}

Case Study

Raw K8s

1. Deploy with just install.
2. curl 127.0.0.1:8080/status to check for result.
3. Manually update the deployment.yaml's ENV value.
4. Redeploy with just install.
5. curl 127.0.0.1:8080/status to check for result change.

Takeaways

1. Requires manually updating in a complicated yaml file.
2. Requires updating multiple location if we decide to change some shared value like port.
3. Not clear to our user which values are expose for customization.

helm chart

1. Deploy with just install
2. curl 127.0.0.1:8080/status to check for result.
3. Manually update the values.yaml's ENV value.
4. Upgrade helm installation with just upgrade.
5. curl 127.0.0.1:8080/status to check for result change.

Takeaways

1. Much more convenient to change common values through values.yaml.
2. Still has difficulty manage different deployment's specific settings.
   • Can't use different branch, as it is not friendly for continuous development.

Kustomization

1. Deploy with just install prod
2. curl 127.0.0.1:8080/status to check for result.
3. just uninstall prod
4. just install dev
5. curl 127.0.0.1:8080/status to check for result change.

Takeaways

1. Much more convenient to maintain settings for different deployments.
2. lack the helm like installation management function (version control, rollback, ...etc).

Helm + Kustomize

1. To be continued...