Basic Helm Commands

All the helm commands are executed in command line interface (helm cli).

1. helm help

This is the command that helps you find out the right command to do something.

2. helm search

There are two ways to search the chart.

2.1. Search in the artifacthub.io - helm search hub <chart name>

2.2. Search in the repository - helm search repo <chart name>

But before run helm search repo <chart name> command, you must ensure that the repo has been added in your machine. To do so, run the command helm repo add <repository url>

3. helm install

Before installing any chart, you must need to ensure that the repository is added locally. To do so, run the command helm repo add <repository url>

To verify if the repo is added or not, use helm repo list command

Now, install the chart using helm install <release name> <repo name>/<chart name>

In the above snapshot, my-prometheus is the release name, prometheus-community is the repo name, and prometheus is the chart name. After installing the chart, validate the resources created in the k8s cluster.

To install a specific version, run the below command helm install <release name> <repo name>/<chart name> --version <version number>

4. helm list

This is the command that helps you list all the releases in your k8s cluster.

5. helm uninstall

This is the command that helps you uninstall the releases in your k8s cluster.

After uninstalling the chart, validate the resources deleted in the k8s cluster.

Sub Commands

You can find the sub commands using helm <command> help

6. helm repo list

This command lists all the repository added in your local machine.

7. helm repo remove

This command lists all the repository removed in your local machine.

Remember that when you install any chart, default values will be picked and created k8s objects in the cluster. You cannot modify that during the installation of the chart

If you want to override the default values, there are three ways.

First approach

Overrides the values through runtime arguments like below

helm install --set <variable name>=<value to override> <repo name>/<chart name>

Example:
helm install --set replicaCount=3 prometheus-community/prometheus

helm install --set replicaCount=3 --set maintainer="satheeshpandianj@gmail.com" prometheus-community/prometheus

Second approach

Keep all the values to be overridden in a separate YAML file and pass that file during installation.

custom-file.yaml

replicaCount: 1
maintainer: "satheeshpandianj@gmail.com"

helm install --values <YAML file name including the path> <repo name>/<chart name>

Example:
helm install --values ~/custom-file.yaml prometheus-community/prometheus

Third approach

Download the chart directory locally and update values.yaml file with updated values. To do so, use the below command

helm pull <repo name> or helm pull --untar <repo name>

Then install the chart from locally. To do so, use the below command helm install <release name> <local repo directory path>

8. helm history

This command helps to see all the revisions for a particular release. helm history <release name>

9. helm rollback

This command helps to roll back to a previous version for a particular release. helm rollback <release name>