Comment 1 for bug 1915727

Weird, because I have managed to run the cells CI job successfully pretty recently (even with ProxySQL shards! lol) in https://review.opendev.org/c/openstack/kolla-ansible/+/770621.

Perhaps it's, as you briefly mentioned, the effect of task delegation which can go wrong depending on your inventory.
Could you share the relevant parts of yours?
It likely differs from CI.