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Join Swarm Manager behind AWS ELB

Is it possible to join manager nodes to a swarm which sits behind an aws internal elb load balancer? Our nodes are auto-scaled up with a pre-built ami which pulls the manager token from a k/v store. It can also pull the leader ip which is required to join the swarm, however i would like to use a load balancer dns record to ensure the new node can still join if the previous leader and its ip address has been replaced.

After placing the managers behind the ELB, I have been unsuccessful in new nodes joining the swarm though the new DNS address. I have received TCP handshake errors if any attempt. I have allowed and forward the following ports through the new ELB (which are all available from the nodes):

All ports are TCP: 2376. 2377. 7946, 4789. I think the issue is the unavailable of UDP between all the nodes now that they go through ELB (which does not support UDP). Another thought it the inability to use DNS names when joining due SSL mismatch.

Has anyone been able to configure a swarm behind an ELB? - any pointers are very much appreciated!

Running: docker-ce=18.06.1~ce~3-0~ubuntu
OS: ubuntu-xenial-16.04-amd64-server