Basic Commands

1. helm install: This command is used to install a chart and create a new release. Example: helm install my-release stable/mysqlUse case: Installing a MySQL database using the stable/mysql chart.
2. helm upgrade: This command is used to upgrade a release to a new version of a chart or modify its configuration.Example: helm upgrade my-release stable/mysql --set mysqlRootPassword=newpasswordUse case: Upgrading the my-release MySQL database to a new version and changing the root password.
3. helm rollback: This command is used to roll back a release to a previous version.Example: helm rollback my-release 1 Use case: Reverting the my-release MySQL database to version 1 after encountering issues with version 2.
4. helm delete: This command is used to delete a release and free up the resources associated with it.Example: helm delete my-release Use case: Removing the my-release MySQL database from the Kubernetes cluster.
5. helm list: This command is used to list all the installed releases.Example: helm listUse case: Checking the list of installed releases in the cluster.
6. helm status: This command is used to get the status of a release.Example: helm status my-releaseUse case: Checking the status of the my-release MySQL database.
7. helm search: This command is used to search for available charts in Helm repositories.Example: helm search repo mysqlUse case: Searching for available MySQL-related charts in Helm repositories.
8. helm dependency update: This command is used to download the dependencies for a chart.Example: helm dependency update my-chartUse case: Downloading the dependencies required for the custom chart named my-chart.

Intermediate Commands

1. helm repo add: This command is used to add a Helm repository to your local environment.Example: helm repo add stable https://charts.helm.sh/stableUse case: Adding the stable repository to your local Helm environment to access charts from the stable repository.
2. helm repo update: This command is used to update the local cache of Helm repositories.Example: helm repo updateUse case: Refreshing the local cache to ensure that you have the latest versions of the charts from the added repositories.
3. helm lint: This command is used to lint a chart to validate its syntax and configuration.Example: helm lint my-chartUse case: Checking the syntax and configuration of a custom chart named my-chart to ensure it is valid.
4. helm package: This command is used to package a chart directory into a compressed chart archive.Example: helm package my-chartUse case: Creating a compressed chart archive from a chart directory named my-chart to distribute or install it locally.
5. helm history: This command is used to view the release history of a chart.Example: helm history my-releaseUse case: Viewing the history of the my-release chart, including the revision numbers, dates, and statuses of the previous releases.
6. helm show: This command is used to display information about a chart or a release.Example: helm show chart stable/mysqlUse case: Displaying information about the stable/mysql chart, such as its description, maintainers, and dependencies.
7. helm template: This command is used to render a chart locally without installing it.Example: helm template my-chartUse case: Generating the Kubernetes manifests from a chart named my-chart without deploying it, useful for inspection or customization purposes.

Deploying a Chart to Kubernetes Cluster

	# Confirm Helm version
	$ helm version
	# Add a helm repository to use the charts in the following demos
	# using this custom repository as the charts in the stable repository have been deprecated.
	$ helm repo add stable https://charts.helm.sh/stable
	# Search for a chart
	$ helm search repo stable/mysql
	# confirm current context
	$ kubectl config current-context
	# test connection to cluster
	$ kubectl get nodes
	# list helm repositories
	$ helm repo list
	# search repository for a mysql chart
	$ helm search repo stable/mysql
	# show chart definition
	$ helm show chart stable/mysql
	# show chart README
	$ helm show readme stable/mysql
	# pipe README to file
	$ helm show readme stable/mysql > C:\Temp\README.txt
	# show chart values
	$ helm show values stable/mysql > C:\Temp\values.txt
	# test deployment of chart
	$ helm install mysql stable/mysql --dry-run --debug
	# deploy chart
	$ helm install mysql stable/mysql
	# confirm deployment
	$ helm list

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Retrieving information about a Release

	# view deployments
	$ helm list
	# view status of release
	$ helm status mysql
	# get release manifests
	$ helm get manifest mysql > C:\Temp\manifests.txt
	# get release values - no user values were supplied so file will be blank
	$ helm get values mysql > C:\Temp\values.txt
	# get release notes
	$ helm get notes mysql > C:\Temp\notes.txt
	# get all from release
	$ helm get all mysql > C:\Temp\all.txt
	# view kubernetes objects
	$ kubectl get all
	# view release history
	$ helm history mysql
	# uninstall a release
	$ helm uninstall mysql --keep-history
	# confirm
	$ helm list
	# confirm with --all flag
	$ helm list --all
	# delete release
	$ helm delete mysql
	# confirm with --all flag
	$ helm list --all

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Upgrading a Release

	# search the repository for a chart
	$ helm search repo stable/mysql
	# search the stable repository for a chart and retrieve the different versions (2 in the repo)
	$ helm search repo stable/mysql --versions
	# install a specific version of the chart
	$ helm install mysql stable/mysql --version 1.6.3
	# confirm release deployed
	$ helm list
	# view kubernetes objects
	$ kubectl get all
	# upgrade the release
	$ helm upgrade mysql stable/mysql --version 1.6.4
	# confirm release upgraded
	$ helm list
	# view history of release
	$ helm history mysql
	# view kubernetes objects
	$ kubectl get all

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Rolling back a Release

	# view release
	helm list
	# view release history
	helm history mysql
	# view kubernetes objects
	kubectl get all
	# view replicasets
	kubectl get replicasets
	# rollback release
	helm rollback mysql 1
	# view release history
	helm history mysql
	# view kubernetes objects
	kubectl get all
	# view replicasets
	kubectl get replicasets
	# view secrets
	kubectl get secrets
	###################################################################################################
	# Rolling back without the old replicaset
	###################################################################################################
	# clean up previous release
	helm delete mysql
	# deploy specific version of chart
	helm install mysql stable/mysql --version 1.6.3
	# upgrade release
	helm upgrade mysql stable/mysql --version 1.6.4
	# confirm history
	helm history mysql
	# view kubernetes objects
	kubectl get all
	# view replicasets
	kubectl get replicaset
	# delete old replicaset - replace NAME with the old replicaset name
	kubectl delete replicaset NAME
	# confirm deletion
	kubectl get replicaset
	# try a rollback with kubectl - will fail as we have deleted the old replicaset
	kubectl rollout undo deployment/mysql
	# but we still have the history of the release in Helm
	helm history mysql
	# rollback with helm
	helm rollback mysql 1
	# confirm status of release
	helm list
	# confirm rollback
	helm history mysql
	# view replicaset
	kubectl get replicaset
	# the old replicaset is back!
	# this is due to the release history being stored as secrets in the k8s cluster
	kubectl get secrets
	# let's a look at one of those secrets
	kubectl get secret sh.helm.release.v1.mysql.v1 -o yaml
	$ kubectl get secret sh.helm.release.v1.mysql.v1 -o jsonpath="{ .data.release }" | base64 -d | base64 -d | gunzip -c | jq '.chart.templates[].data' | tr -d '"' | base64 -d
	# the secret is encoded. For further information on decoding these secrets, see here: -
	# https://dbafromthecold.com/2020/08/10/decoding-helm-secrets/

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Helm Tutorials: helm show commands

	helm show chart: Displays the information and metadata of a chart.
	$ helm show chart mychart
	helm show readme: Shows the README file of a chart.
	helm show readme mychart
	helm show values: Displays the default values.yaml file of a chart.
	$ helm show values mychart
	helm show all: Shows all the information available for a chart, including its metadata, README, and values.
	$ helm show all mychart

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Rajesh Kumar

I’m a DevOps/SRE/DevSecOps/Cloud Expert passionate about sharing knowledge and experiences. I am working at Cotocus. I blog tech insights at DevOps School, travel stories at Holiday Landmark, stock market tips at Stocks Mantra, health and fitness guidance at My Medic Plus, product reviews at I reviewed , and SEO strategies at Wizbrand. 

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