Helm - the Better Way to Deploy on Kubernetes - Reinhard Nägele - Codemotion Amsterdam 2018
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The document presents an overview of Helm, a package manager for Kubernetes that simplifies the deployment and management of applications. It covers Helm's architecture, key features, templating capabilities, dependencies, and lifecycle hooks. Additionally, it includes examples of usage commands and showcases a demo project for practical illustration.
Helm - the Better Way to Deploy on Kubernetes - Reinhard Nägele - Codemotion Amsterdam 2018
- 1. Reinhard Nägele The Better Way to Deploy on Kubernetes 1 AMSTERDAM | MAY 8-9, 2018
- 2. 2 Reinhard Nägele •Senior IT Consultant at codecentric AG •Kubernetes Helm Charts Maintainer •@unguiculus
- 3. The Package Manager for Kubernetes Compare •Apt •Yum •Homebrew •Chocolatey •… 3
- 5. Terminology •Chart A Helm package. Bundles together a set of Kubernetes resource definitions •Repository Hosts a collection of charts on an HTTP server •Release An instance of a chart running in a Kubernetes cluster 5
- 6. Features •Manage Kubernetes resources as a single unit •Charts can be hosted in a repository •Release history •Go templating support •Access to Kubernetes capabilities •Lifecycle management with hooks •Dependencies •PGP support •Plugin support 6
- 7. Helm Architecture 7 Helm Client Tiller gRPC K8s API Server
- 8. Helm CLI 8 helm init Set up Helm on the cluster helm install/upgrade Install or upgrade a chart helm get/status/list Find out information about running charts helm search Search charts in a repository helm create Create a new chart helm template Render chart templates locally
- 10. Chart.yaml name: redis version: 1.0.4 appVersion: 4.0.2 description: Open source, advanced key-value store. keywords: - redis - keyvalue - database home: http://redis.io/ icon: https://bitnami.com/assets/stacks/redis/img/redis-stack-220x234.png sources: - https://github.com/bitnami/bitnami-docker-redis maintainers: - name: bitnami-bot email: [email protected] 10
- 12. Templating •Standard Kubernetes YAML manifest files •Parameterizable via Go template language •Includes the Sprig template library with lots of additional functions •Chart should provide default values in values.yaml 12 image: {{ .Values.image.repository }}:{{ .Values.image.tag }} imagePullPolicy: {{ .Values.image.pullPolicy }}
- 13. Templating — Flow Control 13 if/else/else if for creating conditional blocks with to specify a scope range which provides a “for each”-style loop
- 14. Templating — Built-in Objects •Values •Release (Release.Name, Release.Namespace, …) •Chart (Chart.Name, Chart.Version, …) •Files (Files.Get, Files.GetBytes) •Capabilities (Capabilities.APIVersions, Capabilities.KubeVersion, …) •Template (Template.Name, Template.BasePath) 14
- 15. Templating — Partials 15 {{- define "sample.labels" }} app: {{ template "sample.name" . }} component: server {{- end }} {{- define "MY_NAME" }} # body of template here {{- end }} apiVersion: apps/v1beta2 kind: Deployment metadata: name: {{ template "sample.fullname" . }} labels: {{ include "sample.labels" . | indent 4 }}
- 16. Dependencies 16 dependencies: - name: apache version: 1.2.3 repository: https://example.com/charts - name: mysql version: 3.2.1 repository: https://another.example.com/charts $ helm dependency build demo-app Hang tight while we grab the latest from your chart repositories... ...Successfully got an update from the "local" chart repository ...Successfully got an update from the "stable" chart repository ...Successfully got an update from the "example" chart repository ...Successfully got an update from the "another" chart repository Update Complete. Happy Helming! Saving 2 charts Downloading apache from repo https://example.com/charts Downloading mysql from repo https://another.example.com/charts requirements.yaml
- 17. Hooks •Perform operations at strategic points in a release lifecycle •Can be weighted for ordering •Resources a hook creates are not tracked or managed as part of the release 17 ‣ pre-install ‣ post-install ‣ pre-delete ‣ post-delete ‣ pre-upgrade ‣ post-upgrade ‣ pre-rollback ‣ post-rollback apiVersion: batch/v1 kind: Job metadata: name: demo-job annotations: "helm.sh/hook": post-delete "helm.sh/hook-delete-policy": hook-succeeded spec: …
- 18. Installing Charts •helm install <chart> •helm install <chart> --name <release> •helm upgrade <release> <chart> •helm upgrade <release> <chart> --install 18 $ helm upgrade proxy stable/traefik --install -f traefik-values.yaml --set dashboard.enabled=true --debug
- 19. Tests 19 •Sanity checks for chart releases •Pod specification with test commands to run •Triggered by test hook annotations ‣ helm.sh/hooks: test-success ‣ helm.sh/hooks: test-failure apiVersion: v1 kind: Pod metadata: name: my-app-test annotations: "helm.sh/hook": test-success spec: containers: - name: my-app-test image: foo/my-app-test:42 ...
- 21. 21 Thank you Reinhard Nägele https://github.com/unguiculus @unguiculus Slides licensed under a Creative Commons Attribution- NonCommercial-ShareAlike 4.0 International License.