kubernetes, devops,

Helm Chart

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This document represents an upstream version created during my learning process, proof-of-concepts (PoCs), and other experimental practices. The complete and finalized version of this document might be published on the website techbeatly.com and will be periodically updated.

Using Helm Helm Commands

Installing Helm

Installation doc

Use scripts or package managers.

$ curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

## or
$ brew install helm

Check version

$ helm version
version.BuildInfo{Version:"v3.8.0", GitCommit:"d14138609b01886f544b2025f5000351c9eb092e", GitTreeState:"clean", GoVersion:"go1.17.6"}

$ helm version --short

Helm Repositoty aka Artifact Hub

Artifact Hub is the place where you can find the Kubernetes package bundles.

Managing Helm Chart Repositories

helm repo add stable REPO_URL
helm repo add stable https://charts.helm.sh/stable

helm repo list                    # list repos

helm search repo [keyword] [flags]
helm search repo stable
helm search repo stable/tomcat    # search for repos
helm search hub                   # search in the artifact hub

helm repo update                  # update local helm charts from repo

helm env                          # show environment
helm list                         # display deployed apps

Updating helm local chart list

$ helm repo update
Hang tight while we grab the latest from your chart repositories...
...Successfully got an update from the "stable" chart repository
...Successfully got an update from the "bitnami" chart repository
Update Complete. ⎈Happy Helming!⎈

Creating Helm chart

$ helm create my-chart

The chart skeleton will be created in a directory as shown below.

$ tree myapp-chart 
├── Chart.yaml
├── charts
├── templates
│   ├── NOTES.txt
│   ├── _helpers.tpl
│   ├── deployment.yaml
│   ├── hpa.yaml
│   ├── ingress.yaml
│   ├── service.yaml
│   ├── serviceaccount.yaml
│   └── tests
│       └── test-connection.yaml
└── values.yaml

3 directories, 10 files
  • Chart.yaml - metadata about the chart
  • charts - directory containing other charts
  • templates - k8s manifest template files
  • templates/helpers.tpl - Go template helpes
  • templates/hpa.yaml - Kubernetes horizontal pod autoscaler (HPA) template
  • templates/values.yaml - default values for the chart

Deploying applications using helm

Note: Make sure you have access to Kubernetes or OpenShift cluster from your current environment.

Search for repos and find the appropriate one.

$ helm search repo nginx

## search for pre-releases
$ helm search repo nginx --devel  

## search for specific versions
$ helm search repo nginx-ingress --version ^1.0.0

Select and add the repo (in this case bitnami)

$ helm repo add bitnami https://charts.bitnami.com/bitnami

Install application (eg: bitnami/nginx)

$ helm install nginx-web-server bitnami/nginx
NAME: nginx-web-server
LAST DEPLOYED: Sat Jan 29 12:14:33 2022
NAMESPACE: default
STATUS: deployed

** Please be patient while the chart is being deployed **

NGINX can be accessed through the following DNS name from within your cluster:

    nginx-web-server.default.svc.cluster.local (port 80)

To access NGINX from outside the cluster, follow the steps below:

1. Get the NGINX URL by running these commands:

  NOTE: It may take a few minutes for the LoadBalancer IP to be available.
        Watch the status with: 'kubectl get svc --namespace default -w nginx-web-server'

    export SERVICE_PORT=$(kubectl get --namespace default -o jsonpath="{.spec.ports[0].port}" services nginx-web-server)
    export SERVICE_IP=$(kubectl get svc --namespace default nginx-web-server -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
    echo "http://${SERVICE_IP}:${SERVICE_PORT}"

You can also deploy application using local helm charts by helm install APP_NAME HELM_CHART_DIRECTORY

helm install nodejs-demoapp helm-chart-efk-stack

Verify the deployment

$ kubectl get all
NAME                                  READY   STATUS    RESTARTS   AGE
pod/nginx-web-server-7d9489c4-xzbz9   1/1     Running   0          5m50s

NAME                       TYPE           CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
service/kubernetes         ClusterIP       <none>        443/TCP        129m
service/nginx-web-server   LoadBalancer   <pending>     80:32565/TCP   5m50s

NAME                               READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/nginx-web-server   1/1     1            1           5m50s

NAME                                        DESIRED   CURRENT   READY   AGE
replicaset.apps/nginx-web-server-7d9489c4   1         1         1       5m50s

Remove deployment

## remove the release from the cluster
$ helm uninstall nginx-web-server 
## delete deployment and release history
$ helm delete nginx-web-server 

Download helm charts

helm pull bitnami/nginx

Package and Distribute helm charts

helm package ./myapp-chart 
Successfully packaged chart and saved it to: /Users/gini/workarea/cp/myapp-chart-0.1.0.tgz

Using variables

helm install my-app-1 my-app --values app-1.values.yaml
helm install my-app-2 my-app --values app-2.values.yaml

Managing releases

helm install [NAME] [CHART]
helm upgrade [RELEASE][CHART]
helm rollback <RELEASE> [REVISION] [flags]
helm history [NAME]


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