Kraken is sadly a dead project, with little work being done. For example support for Containerd is non-existent or just not documented.
I created Spegel to fill the gap but focus on the P2P registry component without the overhead of running a stateful application.
https://github.com/spegel-org/spegel
Some self promotion but I have built a project that aims to solve some of these issues in Kubernetes.
https://github.com/xenitAB/spegel
I have avoided a couple of incidents caused by images being removed or momentarily not reachable with it. It would at least mitigate any immediate issues caused by images being removed from Docker Hub.
I created Spegel to fill the gap but focus on the P2P registry component without the overhead of running a stateful application. https://github.com/spegel-org/spegel