Comment 13 for bug 1740892

As mentioned by Mario @ #10, stopping corosync while pacemaker runs throws the same error as the upgrade. Syslog from Xenial + corosync=2.3.5-3ubuntu1:

Jan 8 16:24:37 xenial-corosync systemd[1]: Stopping Pacemaker High Availability Cluster Manager...
Jan 8 16:24:37 xenial-corosync pacemakerd[28747]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync crmd[28753]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync crmd[28753]: notice: State transition S_IDLE -> S_POLICY_ENGINE [ input=I_SHUTDOWN cause=C_SHUTDOWN origin=crm_shutdown ]
Jan 8 16:24:37 xenial-corosync pengine[28752]: notice: Delaying fencing operations until there are resources to manage
Jan 8 16:24:37 xenial-corosync pengine[28752]: notice: Scheduling Node xenial-corosync for shutdown
Jan 8 16:24:37 xenial-corosync pengine[28752]: notice: Calculated Transition 1: /var/lib/pacemaker/pengine/pe-input-52.bz2
Jan 8 16:24:37 xenial-corosync crmd[28753]: notice: Transition 1 (Complete=1, Pending=0, Fired=0, Skipped=0, Incomplete=0, Source=/var/lib/pacemaker/pengine/pe-input-52.bz2): Complete
Jan 8 16:24:37 xenial-corosync crmd[28753]: notice: Disconnecting from Corosync
Jan 8 16:24:37 xenial-corosync cib[28748]: warning: new_event_notification (28748-28753-12): Broken pipe (32)
Jan 8 16:24:37 xenial-corosync pengine[28752]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync attrd[28751]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync lrmd[28750]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync stonith-ng[28749]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync cib[28748]: notice: Invoking handler for signal 15: Terminated
Jan 8 16:24:37 xenial-corosync cib[28748]: notice: Disconnecting from Corosync
Jan 8 16:24:37 xenial-corosync cib[28748]: notice: Disconnecting from Corosync
Jan 8 16:24:37 xenial-corosync systemd[1]: Stopped Pacemaker High Availability Cluster Manager.

Pacemakerd shuts down sending SIGTERM to its components, but after the install, corosync does not start pacemaker. BTW, "systemctl restart corosync" restarts both services perfectly

I think that the option A from James Page (#11) is the way to go