Helm – The package manager for Kubernetes
- 1. Helm The package manager for Kubernetes Fabian Rosenthal <code@xennis.org>
- 2. Introduction
- 3. Motivation ● Install common software ○ Use ready YAMLs instead of starting from scratch ● Different continuous integration stages ○ Reuse and parameterise your YAMLs instead of duplicating them
- 4. Introduction ● Tool for managing Kubernetes charts ● Charts are packages of pre-configured Kubernetes resources ○ Example repository: https://github.com/kubernetes/charts
- 5. Introduction ● Consists of a client (Helm) and a server (Tiller) ○ Helm runs outside of the cluster ○ Tiller runs inside the cluster and manages releases Kubernetes API TillerHelm
- 6. Install or upgrade a release Kubernetes API API server Tiller Pod Helm Fuu Deployment Fuu Service Fuu Config
- 7. Setup
- 8. Install Helm ● Download the binary: https://github.com/kubernetes/helm#install ● Add it to your $PATH ● Enable completion: source <(helm completion zsh)
- 9. Initialize Helm and install Tiller ● Create a cluster $ minikube start ● Install Tiller $ helm init $ kubectl get pods --namespace kube-system Kubernetes API Helm Tiller
- 10. Create a service account ● Create a service account and role $ kubectl create serviceaccount --namespace kube-system tiller $ kubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tiller ● Adjust Tiller deployment to use account $ kubectl patch deploy --namespace kube-system tiller-deploy -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}' Source: https://github.com/kubernetes/helm/issues/2224#issuecomment-299939178
- 12. Install a release ● Install a release $ helm install --name <release> <chart> ● Manage release(s) $ helm ls $ helm delete <release> $ helm status <release>
- 13. Upgrade and rollback a release ● Upgrade a release $ helm upgrade -f config.yaml <release> <chart> ● List release history and rollback to a revision $ helm history <release> $ helm rollback <release> <revision>
- 14. Monitoring with Prometheus Running Prometheus with alert manager, push gateway and k8s monitoring? Just one line: $ helm install stable/prometheus (See: https://github.com/kubernetes/charts/tree/master/stable/prometheus)
- 15. Prometheus $ kubectl port-forward <pod> 9090
- 16. Upgrade the Prometheus release ● Change configuration in command line $ helm upgrade my-release stable/prometheus --set alertmanager.enabled=false ● Change configuration by a values file $ cat config.yaml alertmanager: enabled: true $ helm upgrade my-release stable/prometheus -f config.yaml
- 17. Cloud launcher with Kubeapps ● Install Kubeapps ● Deploy it and start the dashboard $ kubeapps up $ kubeapps dashboard ● Remove it $ kubeapps down
- 19. Create a chart
- 20. Create a chart ● Create a new chart $ helm create <name> ● Create a package and install it $ helm package <name> $ helm install <name>-0.1.0.tgz
- 21. Files of a chart ● Charts.yaml: Information about the chart ● requirements.yaml: Listing dependencies ● values.yaml: Default configuration values ● templates/*.yaml: Templates ● templates/_*: Helpers ● templates/NOTES.txt: Usage notes (See also: https://docs.helm.sh/developing_charts/)
- 22. Write a template ● Built-in objects ○ Chart, Release, Values, ... ● Control structures ○ if/else, range, ... ● Functions ○ default, quote, upper, sha256sum, … ○ Most can be pipelined: {{ .Values.favorite.city | default "Hamburg" | quote }}
- 23. Check a chart ● Verify chart is well-formed $ helm lint <name> ● Render chart templates locally $ helm template <name>
- 24. Useful Kubernetes tools ● Kubetest (https://github.com/garethr/kubetest) ○ Unit test Kubernetes configurations ● Kubeval (https://github.com/garethr/kubeval) ○ Validate Kubernetes configuration supports multiple Kubernetes versions
- 25. … and
- 26. Organize charts for all your services ● One chart for all services or one chart per service? ● Helpful ○ Subcharts of a chart can be created ○ Chart with a dependency to another chart can be defined
- 27. Links ● Helm documentation https://docs.helm.sh ● Dirk Jablonski “Steering the course with Helm” https://www.slideshare.net/djablonski/steering-the-course-with-helm ● Helm repository https://github.com/kubernetes/helm ● Helm charts https://github.com/kubernetes/charts