Helm chart assignment

Tools

• Helm CLI tool
• Recommended editor: Visual Studio Code + Kubernetes extension

Docs

• Getting Started | Helm
• Chart Development Tips and Tricks
• Debugging Templates

Useful commands

• Create chart skeleton: helm create <chart-name>
• Install chart: helm install <release-name> ./gateway-chart -f values-dev.yml (-n <namespace>)
• Upgrade chart: helm upgrade <release-name> ./gateway-chart (-n <namespace>)
  • useful flags: --reset-values --atomic
• Release history: helm history <release-name> (-n <namespace>)
• Release rollback: helm rollback <release-name> <revision> (-n <namespace>)

Tasks

Task 1: Install and experiment with simplest-chart

Demos the absolute basics of a Helm chart. simple-chart only has a single kubernetes Deployment, a ConfigMap and 2 template values.

1. Install: helm install simple ./simplest-chart
2. Test the deployment: kubectl port-forward deploy/simplest-nginx 8888:80
3. Enable HTML override: helm upgrade simple ./simplest-chart --set overrideHtml=true
4. What happened to the deployment's website? Try changing the HTML in the ConfigMap
5. Change image: helm upgrade simple ./simplest-chart --set imageTag=stable
6. Uninstall: helm uninstall simple

In the above commands simple is the release-name. It can be installed several times under different names & namespaces.

Try installing in a different namespace:

1. Create namespace: kubectl create namespace demo
2. Install into namespace: helm install simple ./simplest-chart --namespace demo, what happens?

Task 2: Implement TODOs in gateway-chart

1. Install gateway-chart.
2. Test that the basics are working according to NOTES.txt output.
3. Implement the TODOs in templated manifests.

Success criteria:

• Value api.enabled toggles /api route to the backend container.
• Value service.port controls the exposed port of the nginx proxy.
• Value backend.port controls which port the backend exposes and nginx proxies to (if enabled).
• Value backend.text changes the backend /api response.
• Value replicaCount affects number of pods.

“Definition of done” checks

• helm lint ./gateway-chart passes.
• helm template ./gateway-chart renders valid YAML.

After install:

• / returns gateway text
• /api returns backend text

Task 3: Break stuff!

Break your app, then fix it again:

1. Upgrade the chart using -f values-broken.yml
2. Try to deploy using --atomic --timeout 10s, what happens?
3. Check the values-broken.yml comments
4. Answer and solve the issues one by one.

Task 4: Install 2 versions of gateway-chart at the same time!

1. Install 2 versions of gateway-chart in each their namespace use --namespace x when installing).
2. Do they conflict? How to fix this?

Task 5: Installing from repository

• Charts can be installed from a repository
• Add a repository: helm repo add <name> <url>
• Search for available apps helm search repo <repo>
• Check available versions of specific chart helm search repo <repo>/<chart> --versions
• Install a given app: helm install <repo>/<chart> --version "1.2.3."

Suggested repos you can add:

• https://helm.github.io/examples (hello-world app)
• https://helm.elastic.co (elasticsearch)
• https://charts.gitlab.io/ (gitlab)
• https://github.com/cdwv/awesome-helm?tab=readme-ov-file#repositories--hubs