The Isolated Cluster API was implemented with using the deprecated registry.mirrors configuration.
NOTE: registry.mirrors and registry.configs as previously described in this document have been DEPRECATED. As described in the cri config you should now use the following configuration
The Isolated Cluster API was implemented with using the deprecated registry.mirrors configuration.
https://github.com/containerd/containerd/blob/main/docs/cri/registry.md
Working example with the new configuration: https://github.com/robertvolkmann/containerd-registry-mirror