Running a simple Docker Swarm on LXD v.5.0 on Ubuntu Focal Kernel v. 5.13.0-40-generic - in a Ubuntu Focal LXD container - we see that the service containers we spin up are unreachable on the network. “Normal” Docker containers work fine and port forwarding works fine in those cases, but Docker Swarm is not functional and we cannot reach the containers neither via localhost or the LXD container public IP.
We have trawled through ancient posts 4+ years old on this subject and have tried literally everything suggested:
- Made sure br_netfilter is enabled and as far as we could tell the old issues with that should have been solved in kernel v5.3 already
- Enabled ipv4 forwarding as suggested in one post
- Tried running the LXD container privileged
No obvious errors in the docker logs other than warnings concerning ip_vs kernel module not being available, but as far as I can gather that should not be the cause here (I may be wrong)
Given the lack of posts for a few years now on this topic, it almost seems to me this is a “solved issue” already and in that case we may be missing something obvious.
Does anybody out there have Docker Swarm working in LXD, and if so, what is the magic sauce?
Please ask if you want/need any additional details