I have two unprivileged containers and I'd like to share a unix socket between them. Each container has its own user on the host, complete with separate subuid and subguid mappings.
I've tried creating groups in the containers and mapping them to one group on the host. However, this doesn't work. I'd prefer not to create additional users, to keep the number of users involved and potential security leaks as small as possible, without exposing the containers to one another.