Virtual Registry 0.6.0

Released: 2025-11-27

Varnish version: 6.0.16r7

Added

Added support for persisted storage categories.
Added optional book_size to tune the size of persisted storage books.
Added default_ttl, default_grace, and default_keep options for Virtual Registries to override the global varnish.params with the same name. Like the global params, these only apply to responses that don’t have an explicit cache policy or Cache-Control header from the remote registry.

The configuration format for varnish.storage has changed. While this technically a breaking change, it’s a licensed feature that has not been put in production anywhere yet. We saw this as an opportunity to do some final polish on the config format without introducing a real breaking change.
When possible, requests for package manifests are now coalesced when multiple clients request the same manifest at the same time. This can reduce repeat requests to the remote registry while always keeping the manifests fresh.
Artifacts classified as “other” no longer share a cache namespace with artifacts classified with a specific package type. This resulted in inconsistent cache policies being applied to certain objects, giving them a longer than intended lifetime.
Registries now have separate cache namespaces. This eliminates potential issues with staging/production setups where repositories and packages have the same name but different manifests. Objects with an immutable cache policy still share a global namespace, so cross-registry Docker layer caching will continue tow work as normal.
Introduced Stale-If-Error for all cacheable objects, delivering stale objects in case the remote registry is unreachable or produces 5xx responses. Access control for private repositories is still maintained, relying on cached per-user, per-artifact authorization for access control.

Metrics export now works properly without a license.
Several issues fixed in the varnish.storage subsystem. The MSE configuration should now be changed to reflect changes in the storage configuration in all cases.