ceph/systemd/ceph-mon.target

[Unit]
Description=ceph target allowing to start/stop all ceph-mon@.service instances at once
PartOf=ceph.target
Before=ceph.target
Wants=ceph.target

[Install]
WantedBy=multi-user.target ceph.target
fine-grained control systemd to start/stop/restart ceph services at once Signed-off-by: Zhi Zhang <zhangz.david@outlook.com> 2015-10-26 07:13:19 +00:00			`[Unit]`
			`Description=ceph target allowing to start/stop all ceph-mon@.service instances at once`
			`PartOf=ceph.target`
systemd: Add explicit Before=ceph.target The PartOf= and WantedBy= directives in the various systemd unit files and targets create the following logical hierarchy: - ceph.target - ceph-fuse.target - ceph-fuse@.service - ceph-mds.target - ceph-mds@.service - ceph-mgr.target - ceph-mgr@.service - ceph-mon.target - ceph-mon@.service - ceph-osd.target - ceph-osd@.service - ceph-radosgw.target - ceph-radosgw@.service - ceph-rbd-mirror.target - ceph-rbd-mirror@.service Additionally, the ceph-{fuse,mds,mon,osd,radosgw,rbd-mirror} targets have WantedBy=multi-user.target. This gives the following behaviour: - `systemctl {start,stop,restart}` of any target will restart all dependent services (e.g.: `systemctl restart ceph.target` will restart all services; `systemctl restart ceph-mon.target` will restart all the mons, and so forth). - `systemctl {enable,disable}` for the second level targets (ceph-mon.target etc.) will cause depenent services to come up on boot, or not (of course the individual services can be enabled or disabled as well - for a service to start on boot, both the service and its target must be enabled; disabling either will cause the service to be disabled). - `systemctl {enable,disable} ceph.target` has no effect on whether or not services come up at boot; if the second level targets and services are enabled, they'll start regardless of whether ceph.target is enabled. This is due to the second level targets all having WantedBy=multi-user.target. - The OSDs will always start regardless of ceph-osd.target (unless they are explicitly masked), thanks to udev magic. So far, so good. Except, several users have encountered services not starting with the following error: Failed to start ceph-osd@5.service: Transaction order is cyclic. See system logs for details. I've not been able to reproduce this myself in such a way as to cause OSDs to fail to start, but I have managed to get systemd into that same confused state, as follows: - Disable ceph.target, ceph-mon.target, ceph-osd.target, ceph-mon@$(hostname).service and all ceph-osd instances. - Re-enable all of the above. At this point, everything is fine, but if I then subseqently disable ceph.target, then try `systemctl restart ceph.target`, I get "Failed to restart ceph.target: Transaction order is cyclic. See system logs for details." Explicitly adding Before=ceph.target to each second level target prevents systemd from becoming confused in this situation. Signed-off-by: Tim Serong <tserong@suse.com> 2017-06-30 07:24:21 +00:00			`Before=ceph.target`
systemd: Support Graceful Reboot for AIO Node Ceph AIO installation with single/multiple node is not friendly for loopback mount, especially always get deadlock issue during graceful system reboot. We already have `rbdmap.service` with graceful system reboot friendly as below: [Unit] After=network-online.target Before=remote-fs-pre.target Wants=network-online.target remote-fs-pre.target [Service] ExecStart=/usr/bin/rbdmap map ExecReload=/usr/bin/rbdmap map ExecStop=/usr/bin/rbdmap unmap-all This PR introduce: - `ceph-mon.target`: Ensure startup after `network-online.target` and before `remote-fs-pre.target` - `ceph-*.target`: Ensure startup after `ceph-mon.target` and before `remote-fs-pre.target` - `rbdmap.service`: Once all `_netdev` get unmount by `remote-fs.target`, ensure unmap all RBD BEFORE any Ceph components under `ceph.target` get stopped during shutdown The logic is concept proof by <https://github.com/alvistack/ansible-role-ceph_common/tree/develop>; also works as expected with Ceph + Kubernetes deployment by <https://github.com/alvistack/ansible-collection-kubernetes/tree/develop>. No more deadlock happened during graceful system reboot, both AIO single/multiple no de with loopback mount. Also see: - <https://github.com/ceph/ceph/pull/36776> - <https://github.com/etcd-io/etcd/pull/12259> - <https://github.com/cri-o/cri-o/pull/4128> - <https://github.com/kubernetes/release/pull/1504> Fixes: https://tracker.ceph.com/issues/47528 Signed-off-by: Wong Hoi Sing Edison <hswong3i@gmail.com> 2020-08-25 04:16:54 +00:00			`Wants=ceph.target`

fine-grained control systemd to start/stop/restart ceph services at once Signed-off-by: Zhi Zhang <zhangz.david@outlook.com> 2015-10-26 07:13:19 +00:00			`[Install]`
			`WantedBy=multi-user.target ceph.target`