To simplify starting, stopping, and restarting all the services of a particular type (for example all Ceph services, or all MONs, or all OSDs) on a node, Ceph provides the following systemd unit files:

cephadm > ls /usr/lib/systemd/system/ceph*.target
ceph.target
ceph-osd.target
ceph-mon.target
ceph-mgr.target
ceph-mds.target
ceph-radosgw.target
ceph-rbd-mirror.target

To start/stop/restart all Ceph services on the node, run:

root # systemctl start ceph.target
root # systemctl stop ceph.target
root # systemctl restart ceph.target

To start/stop/restart all OSDs on the node, run:

root # systemctl start ceph-osd.target
root # systemctl stop ceph-osd.target
root # systemctl restart ceph-osd.target

Commands for the other targets are analogous.

You can operate individual services using the following parameterized systemd unit files:

ceph-osd@.service
ceph-mon@.service
ceph-mds@.service
ceph-mgr@.service
ceph-radosgw@.service
ceph-rbd-mirror@.service

To use these commands, you first need to identify the name of the service you want to operate. See Section 3.1.3, “Identifying Individual Services” to learn more about services identification.

To start/stop/restart the osd.1 service, run:

root # systemctl start ceph-osd@1.service
root # systemctl stop ceph-osd@1.service
root # systemctl restart ceph-osd@1.service

Commands for the other service types are analogous.

You can find out the names/numbers of a particular type of service in several ways. The following commands provide results for services ceph* and lrbd*. You can run them on any node of the Ceph cluster.

To list all (even inactive) services of type ceph* and lrbd*, run:

root # systemctl list-units --all --type=service ceph* lrbd*

To list only the inactive services, run:

root # systemctl list-units --all --state=inactive --type=service ceph* lrbd*

You can also use salt to query services across multiple nodes:

root@master # salt TARGET cmd.shell \
 "systemctl list-units --all --type=service ceph* lrbd* | sed -e '/^$/,$ d'"

Query storage nodes only:

root@master # salt -I 'roles:storage' cmd.shell \
 'systemctl list-units --all --type=service ceph* lrbd*'

You can query systemd for the status of services. For example:

root # systemctl status ceph-osd@1.service
root # systemctl status ceph-mon@HOSTNAME.service

Replace HOSTNAME with the host name the daemon is running on.

If you do not know the exact name/number of the service, see Section 3.1.3, “Identifying Individual Services”.

Warning: Interruption of Services

If Ceph related services—specifically iSCSI or NFS Ganesha—are configured as single points of access with no High Availability setup, restarting then will result in their temporary outage as viewed from the client side.

Tip: Samba not Managed by DeepSea

Because DeepSea and openATTIC do not currently support Samba deployments, you need to manage Samba related services manually. For more details, see Book “Deployment Guide”, Chapter 13 “Exporting Ceph Data via Samba”.

To restart all services on the cluster, run the following command:

root@master # salt-run state.orch ceph.restart

All roles you have configured restart in the following order: Ceph Monitor, Ceph Manager, Ceph OSD, Metadata Server, Object Gateway, iSCSI Gateway, NFS Ganesha. To keep the downtime low and to find potential issues as early as possible, nodes are restarted sequentially. For example, only one monitoring node is restarted at a time.

The command waits for the cluster to recover if the cluster is in a degraded, unhealthy state.

To restart a specific service on the cluster, run:

root@master # salt-run state.orch ceph.restart.service_name

For example, to restart all Object Gateways, run:

root@master # salt-run state.orch ceph.restart.rgw

You can use the following targets:

root@master # salt-run state.orch ceph.restart.mon

root@master # salt-run state.orch ceph.restart.mgr

root@master # salt-run state.orch ceph.restart.osd

root@master # salt-run state.orch ceph.restart.mds

root@master # salt-run state.orch ceph.restart.rgw

root@master # salt-run state.orch ceph.restart.igw

root@master # salt-run state.orch ceph.restart.ganesha