Custom Assembly Overlays on

Overview of Custom Assembly Overlays

Mon, 28 Sep 2026 16:33:22 +0000

Note: Custom Assembly Overlays is in beta.

Standard Custom Assembly applies one customization to every tag in a repository. This fails for images that ship several language or runtime versions side by side, because a package built for one version can’t install on the others.

For example, the python image publishes tags for Python 3.11, 3.12, 3.13, and 3.14. The py3.13-typer package depends on Python 3.13. If you add it with standard Custom Assembly, every tag tries to install it, and the 3.11, 3.12, and 3.14 builds fail.

Manage Custom Assembly Overlays with chainctl

Mon, 28 Sep 2026 16:33:22 +0000

Note: Custom Assembly Overlays is in beta.

This guide shows how to use chainctl to apply Custom Assembly customizations to some of a repository’s tags, or to every repository in your organization or a folder. You create an overlay that holds the customizations, then bind it with a tag selector.

For an explanation of overlays, bindings, and tag selectors, refer to Overview of Custom Assembly Overlays.

Prerequisites

Before you start, you need the following:

Manage Custom Assembly Overlays with Terraform

Mon, 28 Sep 2026 16:33:22 +0000

Note: Custom Assembly Overlays is in beta.

This guide shows how to manage Custom Assembly Overlays with the Chainguard Terraform provider. You define overlays with the chainguard_image_overlay resource and bind them to repositories with the chainguard_image_overlay_binding resource.

For an explanation of overlays, bindings, and tag selectors, refer to Overview of Custom Assembly Overlays.

The provider doesn’t support all-repos bindings yet; each binding resource names one repository. To bind an overlay to every repository in your organization or a folder, use chainctl.