erlang/rmq is notoriously brittle if the hostname being used ('controller') does not forward and reverse resolve on the host its running on (and all other hosts that you might want to cluster it with).
Please check this is the case: sudo nslookup controller Marking 'Incomplete'; if the hostname controller does not forward/reverse lookup between hostname and IP OK then please fix that and mark this bug as Invalid; otherwise please comment and set back to 'New'. ** Changed in: rabbitmq-server (Ubuntu) Status: New => Incomplete ** Changed in: rabbitmq-server (Ubuntu) Importance: Undecided => Low -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to rabbitmq-server in Ubuntu. https://bugs.launchpad.net/bugs/1558311 Title: package rabbitmq-server 3.5.4-1 failed to install/upgrade: rabbit@controller: * unable to connect to epmd (port 4369) on controller: address (cannot connect to host/port) current node details: - node name: 'rabbitmq-cli-25717@controller' - home dir: /var/lib/rabbitmq - cookie hash: XHLruNjMVi9RPYDcOuJiAQ==subprocess installed post-installation script returned error exit status 1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/rabbitmq-server/+bug/1558311/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs