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Kubernetes Helm

Helm

Helm is a package manager for deploying applicatons.

Adding stable repository

helm repo add <alias> <helm repo>
helm repo add stable https://charts.helm.sh/stable

Search chart in a repo

helm search repo stable/mysql

Deploy application using helm

helm install <Name of the application> <repo/chart-name>
Eg: helm install mysql testing/mysql

Confirm current context

kubectl config current-context

Chart definition

helm show chart <repo/chartname>
helm show readme <repo/chartname>
helm show values <chart-name>

dry run

helm install <name-of -the-application> <chart name>  --dry-run --debug

Confirm deployment

helm list

List pods, services, deployments and replica sets

kubectl get all 

status of the release

helm status <app-deployed>
eg: helm status mysql
helm get manifest <chart-deployed>

View release hhistory

helm history mysql

Unistall a release

helm uninstall mysql --keep-history
helm delete mysql

Show all the version of a helm chart

helm search repo mysql --versions

Install specific version of the chart

helm install mysql daya/mysql --version <version>
eg: helm install mysql testing/mysql --version 1.16.3


Search all the versions for a specific chart

helm search repo "daya/mysql" --versions



Rolling upgrade

helm upgrade mysql daya/mysql --version <version>


helm history mysql
REVISION        UPDATED                         STATUS          CHART           APP VERSION     DESCRIPTION
1               Fri Jan  7 12:42:53 2022        superseded      mysql-1.6.3     5.7.28          Install complete
2               Fri Jan  7 17:50:08 2022        deployed        mysql-1.6.4     5.7.30          Upgrade complete


Rollback 

helm rollback mysql <revision number>

Pull down a chart 

helm pull stable/mysql --untar

Helm Chart Structure

Helm Repository:

Helm repo is any http server which stores tar files.

  1. https://artifacthub.io/
  2. https://hub.helm.sh

Creating helm chart

helm create <chart-name>

Create a simple deployment spec

helm create deployment nginx --image=nginx --dry-run=client --output=yaml

Package the chart

helm package <local location> --destination C:/Charts
















































Happy Learning😀

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