# Why deploy k8s using Helm Normal: - Your app -> hard-code yaml (deployment/service/ingress) -> Kubectl -> AKS => Use Helm to simplify the application deployment process and avoid hardcoded deployment variables and settings. => Repeatable, reliable, manageable, resuable across mutil teams and env New: - Your app -> Helm chart -> AKS Helm components: - Client: is where helm was installed and responsible for creating and submitting the manifest files required to deploy aks application. (Communicate between user and k8s cluster) - Charts: file to describe how the application deployed (chart/value/template) - Releases: The application or a group of application deployed using Chart - Repositories: discoverability and reusability of helm pacakges # Concept If 2 component depends on each other, try to use 1 chart and set the dependency If 2 component are independent, create 1 chart for each component (Easier for bugfix and upgrade) # Commands ```bash title="Create your own chart" helm create (Will create chart file template) ``` # Work with repos ```bash title="Helm repo cli" helm repo add azure-marketplace https://marketplace.azurecr.io/helm/v1/repo helm repo update helm repo list helm search repo ``` # To install a chart (This similar to `kubectl apply` command) Run `helm install` to install a chart from: - Chart folder: `helm install ./drone-webapp` - A packaged `.tgz` tar archive chart: `helm install ./drone-webapp.tgz` - A Helm repository: `helm install azure-marketplace/aspnet-core` ```bash title="Debuging cli" helm install --debug --dry-run ./drone-webapp ``` # Lets install aspnet ```bash title="Step to release using helm" az aks get-credentials -g learn-helm-deploy-aks-rg -n learn-helm-deploy-aks # To release helm install azure-marketplace/aspnet-core # To query all the installed release on the cluster helm list helm get manifest (To get manifest file of a release, optional --revision) helm delete (To delete a realease) # Install with set values helm install --set replicaCount=5 azure-marketplace/aspnet-core # Upgrade a release helm upgrade ./app-chart (This bassically create new revision) helm history helm rollback

(Run helm history to check first) ``` # Write a custom chart or extends it ## Template and function To display the value as a string, you use `{{ quote .Values.ingress.enabled }}` or `{{ .Values.ingress.enabled | quote }}` Chaning mutiple function: `{{ .Values.ingress.enabled | upper | quote }}` Helm chart template support ~60 built-in function ## Conditional ```yml {{- if | pipeline | -}} # Do something {{- else if | other pipeline | -}} # Do something else {{- else -}} # Default case {{- end }} ``` ## List ```yml | value.yml ingress: enabled: true extraHosts: - name: host1.local path: / - name: host2.local path: / - name: host3.local path: / ``` ```yml | template.yml apiVersion: extensions/v1 kind: Ingress metadata: spec: rules: ... {{- range .Values.ingress.extraHosts }} - host: {{ .name }} http: paths: - path: {{ .path }} ... {{- end }} ... ```

helm (1)

Helm learning notes