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Helm Commands

- Command 1: helm ls​

- The command:

helm ls -n NAMESPACE

Or...

helm list -n NAMESPACE

- Description:

This command lists all the releases for a specified namespace (uses current namespace context if namespace not specified).


- Command 2: helm create​

- The command:

helm create CHART_NAME

- Description:

create a new chart with the given name.

This command creates a chart directory along with the common files and directories used in a chart. helm create takes a path for an argument. If directories in the given path do not exist, Helm will attempt to create them as it goes. If the given destination exists and there are files in that directory, conflicting files will be overwritten, but other files will be left alone.

For example, helm create foo will create a directory structure that looks something like this:

foo/
├── .helmignore   # Contains patterns to ignore when packaging Helm charts.
├── Chart.yaml    # Information about your chart
├── values.yaml   # The default values for your templates
├── charts/       # Charts that this chart depends on
└── templates/    # The template files
    └── tests/    # The test files

- Command 3: helm uninstall​

- The command:

helm uninstall RELEASE_NAME -n NAMESPACE

- Description:

Uninstall a release.

This command takes a release name and uninstalls the release. It removes all of the resources associated with the last release of the chart as well as the release history, freeing it up for future use.

The --keep-history flag​

In the past, this was the default. Now, running uninstall deletes everything. If you want to uninstall a chart, but keep its history, use this flag.


- Command 4: helm install​

- The command:

helm install RELEASE_NAME path/to/chart-root --values path/to/values.yaml -n NAMESPACE --debug

- Description:

This command installs a chart archive, and gives it a nickname which you provide.

  • The -f, --values flags specify values in a YAML file or a URL (can specify multiple).
  • The --debug flag enables verbose output.
  • The --dry-run flag simulates an install. --dry-run is similar to --dry-run=client, which means that it will not attempt cluster connections, while setting --dry-run=server attempts to connect the cluster.
  • The --force flag forces resource updates through a replacement strategy.
  • The --verify flag verifies the package before using it.
  • The --wait flag will wait until all Pods, PVCs, Services, and minimum number of Pods of a Deployment, StatefulSet, or ReplicaSet are in a ready state before marking the release as successful. It will wait for as long as --timeout.

The install argument must be a chart reference, a path to a packaged chart, a path to an unpacked chart directory, or a URL.

When using a path to an unpacked chart directory:

  1. The root directory must include a Chart.yaml file.
  2. Inside that Chart.yaml file, you MUST specify:
    • a name field
    • an version field
  3. The root directory needs to include a folder named templates. This isn't required per-say, since the operation won't fail if one does not exist. However, even though running helm ls would show that a chart has been created, nothing would actually be deployed to your cluster! So while technically it is not required, it is sort of required.
  4. The templates folder is where you include all your yaml files, whether it be a config for a deployment, or a service, or a configmap. The names of the files don't matter, since kubernetes/helm looks inside the file and derives what resource it is based on its Kind.
  5. The root folder may include a values.yaml file, to which you would point when invoking the install command, along with the flag of --values.

Another way to set values

To override values in a chart, use either the '--values' flag and pass in a file or use the '--set' flag and pass configuration from the command line, to force a string value use '--set-string'. You can use '--set-file' to set individual values from a file when the value itself is too long for the command line or is dynamically generated. You can also use '--set-json' to set json values (scalars/objects/arrays) from the command line.

- Example Usage:

helm install user ./user --values ./user/values.yaml -n NAMESPACE --create-namespace

- Command 5: helm upgrade​

- The command:

helm upgrade RELEASE_NAME path/to/chart-root --values path/to/values.yaml -n NAMESPACE

- Description:

This command upgrades a release to a new version of a chart.

The upgrade arguments must be a release and chart.

- A. The CHART argument:​

The chart argument can be either: a path to a chart directory, a packaged chart, a fully qualified URL, or a chart reference ('example/mariadb'). For chart references, the latest version will be specified unless the '--version' flag is set.

- B. The --values flag:​

To override values in a chart, use either the --values flag and pass in a file or use the --set flag and pass configuration from the command line, to force string values, use --set-string. You can use --set-file to set individual values from a file when the value itself is too long for the command line or is dynamically generated. You can also use --set-json to set json values (scalars/objects/arrays) from the command line.
You can specify the --values/-f flag multiple times. Priority will be given to the last values.yaml specified (the one on the most-right). If both values.yaml and values-override.yaml contained a key called Test, the value set in values-override.yaml would win.

- C. The --reuse-values flag:​

Re-use values from last release. When upgrading, reuse the last release's values, and merge in any overrides. If --reset-values is specified, this flag ignored.
Imagine this situation: You initially install a chart with...

helm install my-release my-chart --set image.tag=1.0.0 --set replicas=3

Later, you want to only change the image tag:

helm upgrade my-release my-chart --set image.tag=2.0.0

If you don't use --reuse-values, then:

  • replicas will reset to the chart default (e.g., let's say 1),
  • Because you're only passing image.tag, Helm thinks "oh, I should use only these values."

- D. The --dry-run flag​

The --dry-run mode would only go through the first few steps of helm install, meaning it will load the charts, merge values from values.yaml, render the required k8s templates, but it will not submit them to the k8s API server, and thus, will not get created.

To sum up, the --dry-run flag will output all generated chart manifests, including Secrets which can contain sensitive values. You can hide Kubernetes Secrets using the --hide-secret flag. Please carefully consider how and when these flags are used.

- Usage Example:

helm upgrade --install users-service ./toolbox/deploy/charts/users-service --values ./toolbox/deploy/charts/users-service/values.yaml -n application

- Command 6: helm status​

- The command: status

helm status CHART_NAME -n NAMESPACE

- Description:

The helm status commands is useful when using the helm install command. When running helm install, Helm does not wait until all of the resources are running before it exits. Many charts require Docker images that are over 600MB in size, and may take a long time to install into the cluster. So, to keep track of a release's state, or to re-read configuration information, you can use helm status.

Display the status of the named release.

This command shows the status of a named release. The status consists of:

  • last deployment time

  • k8s namespace in which the release lives

  • state of the release (can be: unknown, deployed, uninstalled, superseded, failed, uninstalling, pending-install, pending-upgrade or pending-rollback)

  • revision of the release

  • description of the release (can be completion message or error message, need to enable --show-desc)

  • list of resources that this release consists of (need to enable --show-resources)

  • details on last test suite run, if applicable

  • additional notes provided by the chart


- Command 7: helm history​

- The command:

helm history RELEASE_NAME -n NAMESPACE

- Description:

Fetch a release's history.

history prints out historical revisions for a given release. A default maximum of 256 revisions will be returned. Setting --max configures the maximum length of the revision list returned.


- Command 8: helm rollback​

- The command:

helm rollback RELEASE_NAME REVISION_NUMBER -n NAMESPACE

- Description:

Roll back a release to a previous revision.

The first argument of the rollback command is the name of a release, and the second is a revision (version) number. If this argument is omitted or set to 0, it will roll back to the previous release.


- Command 9: helm template​

- The command:

helm template CHART path/to/chart --values path/to/values.yaml

- Description:

Render chart templates locally and display the output.

Any values that would normally be looked up or retrieved in-cluster will be faked locally. Additionally, none of the server-side testing of chart validity (e.g. whether an API is supported) is done.

The template command outputs clean templates, ready to be used by a kubernetes API server, so if you like doing all the applying job yourself, and just want helm to help you with the creation of the charts, you have an option for that as well.

Note that creating a template does not communicate with the server at all, not even for validating that the resource template yaml is ok. This is as opposed to the --dry-run flag on helm upgrade, which does. This is what makes helm template so useful, that it doesn't need the credentials to talk to a k8x cluster, just to have a template validated.

- Command 10: helm package​

- The command:

helm package path/to/root [flags] --version VERSION_NUMBER --debug

- Description:

Package a chart directory into a chart archive.

This command packages a chart into a versioned chart archive file. If a path is given, this will look at that path for a chart (which must contain a Chart.yaml file) and then package that directory.

Versioned chart archives are used by Helm package repositories.

To sign a chart, use the '--sign' flag. In most cases, you should also provide '--keyring path/to/secret/keys' and '--key keyname'.

helm package --sign ./mychart --key mykey --keyring ~/.gnupg/secring.gpg

If '--keyring' is not specified, Helm usually defaults to the public keyring unless your environment is otherwise configured.


- Command 11: helm get values​

- The command:

helm get values RELEASE_NAME

- Description:

Download the values file for a named release.

Running the command just like that, gives you the values used on this upgrade alone.

The --all flag​

To get all values, use the --all flag.

The --revision flag​

To get values from a specific revision (deployment), use the --revision flag, followed by the number. You can get the number by running helm history CHART.


- Command 12: helm get notes​

- The command:

helm get notes RELEASE_NAME

- Description:

Get the release notes of some named release.


- Command 13: helm get manifest​

- The command:

helm get manifest RELEASE_NAME

- Description:

Download the manifest for a named release.

The manifest is a YAML representation of all the Kubernetes resources that were generated from this release's chart(s).

The --revision flag​

Get the manifest of a specific revision.