User defined network disappeared

Expected behavior

I created an overlay network using:
docker network create --attachable --driver overlay my-overlay-net
I was able to start containers connected to this network and inter-container connectivity using DNS was ok.

Actual behavior

After the overlay network was up and running for ~2 months I experienced DNS errors with inter-container connectivity.
I stopped my containers and attempted to restart them but received the message:
Error response from daemon: network my-overlay-net not found
’docker network ls’ confirmed that the network was gone.
I can’t find any additional output on the swarm nodes to find out why/where the network has gone.

Additional Information

Docker version 1.13.0-rc4, build 88862e7

Steps to reproduce the behavior

May be tricky to reproduce as it ran for quite some time.

  1. Create a user defined overlay network
  2. Start several containers connected to the user defined network
  3. Test DNS connectivity between the containers…
  4. Wait a while and repeat #3 until it fails…