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Docker 19.03.12 : The swarm does not have a leader aferter swarm upgrade

Hello,

Some strange troubleshouting with docker since laste update.

Can you help me about this ?
It’s is not my firstr upgrade of package and this case have been reproduice on a freshnew stack.

Updgraded from 18.09.9 to 19.03.12

OS : Ubuntu 16.04 Server

Docker package
docker-ce=5:18.09.9~3-0~ubuntu-bionic
docker-ce-cli=5:19.03.11~3-0~ubuntu-bionic
containerd.io=1.2.13-2

Details

A problem identified with version 19.03.12 of docker
Managers have been put in version 19.03.12
When you want to add a manager to the group with an active leader, an error message is visible
The different known solutions were used

Error Message

  • The swarm does not have a leader
  • Error response from daemon: rpc error: code = Unknown desc = The swarm does not have a leader. It’s possible that too few managers are online. Make sure more than half of the managers are online.
  • Logs manager non-leader : docker msg=“error reading the kernel parameter net.ipv4.vs.expire_nodest_conn”

Case

  • As soon as you play the docker swarm join --token command on non-leader managers, after a few minutes, the leader manager is no longer available
    -> Forced to replay the docker swarm init command --force-new-cluster --advertise-addr xx.xx.xx.xx --listen-addr xx.xx.xx.xx: 2377 to find the leader operational

  • The leader sees the worker nodes in version 19.03.12. No problem with workers

References applied

i cant add link in the post