On 06/29/2017 05:04 AM, Sage Weil wrote: > There is some goofy behavior with the systemd unit files that tries to > make a new ceph-mgr daemon automagically appear next to the mons during a > cluster upgrade: > > - The ceph-mon@.service triggers ceph-mgr@ to start > - The ceph-mgr@.service tries to create a ceph-mgr key using whatever > mon key it can find > > This was intended to ease the upgrade path by auto-creating ceph-mgr > daemons along the way. It's also helpful for new installs; it means you don't actually have to explicitly configure mgr daemons in order to get a running cluster. You just end up with as many mgrs as mons automatically. That said, it is somewhat obscure, and also can make it slightly irritating if you want to run mgrs on separate nodes (then you have to explicitly deploy mgr, and also either uninstall the ceph-mgr package from the mon nodes, or at least `systemctl mask ceph-mgr@$(hostname)` on those nodes. > Do we really want this? I was reminded this behavior is here because of > #19994, which points out that this isn't implemented for upstart (still > used by trusty 14.04). > > The jewel -> luminous upgrade process is currently documented here > > http://docs.ceph.com/docs/master/release-notes/#upgrade-from-jewel-or-kraken > > and basically has a step that says 'verify mgr daemons are running and, if > not, create some'. Is that sufficient? Probably. Especially given that now ceph-mgr isn't optional (you'll end up with "HEATH_ERR; no active mgr"), there's incentive for everyone to configure some mgr daemons ;-) More seriously: the systemd magic was able to ensure mgr was running with Kraken, prior to the various deployment tools growing support for deploying mgr, and (possibly?) prior to mgr appearing in the docs. That magic still works fine and I personally don't mind keeping it, but if it's going to result in inconsistent automatic behaviour across distros, that's probably bad. Maybe then for Luminous it's best now to drop the magic and require everyone to explicitly configure mgr, as for all other daemons? Regards, Tim -- Tim Serong Senior Clustering Engineer SUSE tserong@xxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
