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Package a Helm Chart for a Release

This topic describes how to package a Helm chart and the Replicated SDK into a chart archive that can be added to a release.

Overview​

To add a Helm chart to a release, you first add the Replicated SDK as a dependency of the Helm chart and then package the chart and its dependencies as a .tgz chart archive.

The Replicated SDK is a Helm chart can be installed as a small service alongside your application. The SDK provides access to key Replicated features, such as support for collecting custom metrics on application instances. For more information, see About the Replicated SDK.

Requirements and Recommendations​

This section includes requirements and recommendations for Helm charts.

Chart Version Requirement​

The chart version in your Helm chart must comply with image tag format requirements. A valid tag can contain only lowercase and uppercase letters, digits, underscores, periods, and dashes.

The chart version must also comply with the Semantic Versioning (SemVer) specification. When you run the helm install command without the --version flag, Helm retrieves the list of all available image tags for the chart from the registry and compares them using the SemVer comparison rules described in the SemVer specification. The version that is installed is the version with the largest tag value. For more information about the SemVer specification, see the Semantic Versioning documentation.

Chart Naming​

For releases that contain more than one Helm chart, Replicated recommends that you use unique names for each top-level Helm chart in the release. This aligns with Helm best practices and also avoids potential conflicts in filenames during installation that could cause the installation to fail. For more information, see Installation Fails for Release With Multiple Helm Charts in Troubleshooting Helm Installations.

Helm Best Practices​

Replicated recommends that you review the Best Practices guide in the Helm documentation to ensure that your Helm chart or charts follows the required and recommended conventions.

Package a Helm Chart​

This procedure shows how to create a Helm chart archive to add to a release. For more information about the Helm CLI commands in this procedure, see the Helm Commands section in the Helm documentation.

To package a Helm chart so that it can be added to a release:

  1. In your application Helm chart Chart.yaml file, add the YAML below to declare the SDK as a dependency. If your application is installed as multiple charts, declare the SDK as a dependency of the chart that customers install first. Do not declare the SDK in more than one chart.

    # Chart.yaml
    dependencies:
    - name: replicated
      repository: oci://registry.replicated.com/library
      version: 1.5.1

    For the latest version information for the Replicated SDK, see the replicated-sdk repository in GitHub.

    For additional guidelines related to adding the SDK as a dependency, see Install the SDK as a Subchart in Installing the Replicated SDK.

  2. Update dependencies and package the chart as a .tgz file:

    helm package -u PATH_TO_CHART

    Where:

    • -u or --dependency-update is an option for the helm package command that updates chart dependencies before packaging. For more information, see Helm Package in the Helm documentation.
    • PATH_TO_CHART is the path to the Helm chart in your local directory. For example, helm package -u ..

    The Helm chart, including any dependencies, is packaged and copied to your current directory in a .tgz file. The file uses the naming convention: CHART_NAME-VERSION.tgz. For example, postgresql-8.1.2.tgz.

    note

    If you see a 401 Unauthorized error after running helm dependency update, run the following command to remove credentials from the Replicated registry, then re-run helm dependency update:

    helm registry logout registry.replicated.com

    For more information, see 401 Unauthorized Error When Updating Helm Dependencies.

  3. Add the .tgz file to a release. For more information, see Manage Releases with the Vendor Portal or Managing Releases with the CLI.

    After the release is promoted, your Helm chart is automatically pushed to the Replicated registry. For information about how to install a release with the Helm CLI, see Install with Helm. For information about how to install Helm charts with KOTS, see About Distributing Helm Charts with KOTS.