As per nacc's comment it seems like "Wants=" is the recommended way to hook start-up of one unit to the start-up of another unit.[1]
[1] - https://www.freedesktop.org/software/systemd/man/systemd.unit.html#Wants= So far I have tested using 2 scenarios (including "Wants=pacemaker.service") and it look good so far. --------------------------------------- * Scenario #1 [Both corosync & pacemaker installed] --------------------------------------- - pacemaker start on corosync start. root@xenialcorosyncpacemaker:~# systemctl status corosync | egrep "PID|Active:" Active: active (running) since Mon 2018-01-08 19:29:44 UTC; 21s ago Main PID: 445 (corosync) root@xenialcorosyncpacemaker:~# systemctl status pacemaker | egrep "PID|Active:" Active: active (running) since Mon 2018-01-08 19:29:44 UTC; 27s ago Main PID: 447 (pacemakerd) root@xenialcorosyncpacemaker:~# systemctl stop corosync root@xenialcorosyncpacemaker:~# systemctl status corosync | egrep "PID|Active:" Active: inactive (dead) since Mon 2018-01-08 19:30:29 UTC; 1s ago Main PID: 445 (code=exited, status=0/SUCCESS) root@xenialcorosyncpacemaker:~# systemctl status pacemaker | egrep "PID|Active:" Active: inactive (dead) since Mon 2018-01-08 19:30:29 UTC; 3s ago Main PID: 447 (code=exited, status=0/SUCCESS) root@xenialcorosyncpacemaker:~# systemctl start corosync root@xenialcorosync:~# systemctl status corosync | egrep "PID|Active:" Active: active (running) since Mon 2018-01-08 19:30:56 UTC; 1s ago Main PID: 474 (corosync) root@xenialcorosyncpacemaker:~# systemctl status pacemaker | egrep "PID|Active:" Active: active (running) since Mon 2018-01-08 19:30:56 UTC; 3s ago Main PID: 476 (pacemakerd) --------------------------------------- * Scenario #2 [corosync installed & pacemaker not installed] --------------------------------------- - It doesn't seem to have any side-effects when pacemaker isn't installed. The Wants= options is simply ignore since the pacemaker.service is not present. root@xenialcorosyncnopacemaker:~# systemctl status corosync | egrep "PID|Active:" Active: active (running) since Mon 2018-01-08 19:32:11 UTC; 53s ago Main PID: 1284 (corosync) root@xenialcorosyncnopacemake:~# systemctl status pacemaker ● pacemaker.service Loaded: not-found (Reason: No such file or directory) Active: inactive (dead) root@v:~# systemctl stop corosync root@xenialcorosyncnopacemake:~# systemctl status pacemaker ● pacemaker.service Loaded: not-found (Reason: No such file or directory) Active: inactive (dead) root@xenialcorosyncnopacemake:~# systemctl status corosync | egrep "PID|Active:" Active: inactive (dead) since Mon 2018-01-08 19:33:17 UTC; 4s ago Main PID: 1284 (code=exited, status=0/SUCCESS) root@xenialcorosyncnopacemake:~# systemctl start corosync root@xenialcorosyncnopacemake:~# systemctl status corosync | egrep "PID|Active:" Active: active (running) since Mon 2018-01-08 19:33:26 UTC; 1s ago Main PID: 1378 (corosync) - Eric -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1740892 Title: corosync upgrade on 2018-01-02 caused pacemaker to fail To manage notifications about this bug go to: https://bugs.launchpad.net/charm-hacluster/+bug/1740892/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
