nslookup on the host itself is 100% fine, but from within container any hostname look fails (can’t event run apt-get update).
The same symptoms persist in all my hosts in the 4-node cluster.
Running the same application directly on my laptop (on same office network) hostnames resolve fine.
This is becoming a bit of a slow moving disaster.
The cluster involved is still a pre-1.12 build, it that might have any bearing.
Just some more info: the containers in question is brought up with docker-compse (latest 1.10 version), with compose file format 2. No DNS settings present.
Duplicating tests from this blog produces a container with correctly functioning DNS (in the same swarm).
So the main difference seems to be the use of docker-compse at this point.