Notice

This document is for a development version of Ceph.

Operating a Cluster

Running Ceph with systemd

In all distributions that support systemd (CentOS 7, Fedora, Debian Jessie 8 and later, and SUSE), systemd files (and NOT legacy SysVinit scripts) are used to manage Ceph daemons. Ceph daemons therefore behave like any other daemons that can be controlled by the systemctl command, as in the following examples:

sudo systemctl start ceph.target       # start all daemons
sudo systemctl status ceph-osd@12      # check status of osd.12

To list all of the Ceph systemd units on a node, run the following command:

sudo systemctl status ceph\*.service ceph\*.target

Starting all daemons

To start all of the daemons on a Ceph node (regardless of their type), run the following command:

sudo systemctl start ceph.target

Stopping all daemons

To stop all of the daemons on a Ceph node (regardless of their type), run the following command:

sudo systemctl stop ceph\*.service ceph\*.target

Starting all daemons by type

To start all of the daemons of a particular type on a Ceph node, run one of the following commands:

sudo systemctl start ceph-osd.target
sudo systemctl start ceph-mon.target
sudo systemctl start ceph-mds.target

Stopping all daemons by type

To stop all of the daemons of a particular type on a Ceph node, run one of the following commands:

sudo systemctl stop ceph-osd\*.service ceph-osd.target
sudo systemctl stop ceph-mon\*.service ceph-mon.target
sudo systemctl stop ceph-mds\*.service ceph-mds.target

Starting a daemon

To start a specific daemon instance on a Ceph node, run one of the following commands:

sudo systemctl start ceph-osd@{id}
sudo systemctl start ceph-mon@{hostname}
sudo systemctl start ceph-mds@{hostname}

For example:

sudo systemctl start ceph-osd@1
sudo systemctl start ceph-mon@ceph-server
sudo systemctl start ceph-mds@ceph-server

Stopping a daemon

To stop a specific daemon instance on a Ceph node, run one of the following commands:

sudo systemctl stop ceph-osd@{id}
sudo systemctl stop ceph-mon@{hostname}
sudo systemctl stop ceph-mds@{hostname}

For example:

sudo systemctl stop ceph-osd@1
sudo systemctl stop ceph-mon@ceph-server
sudo systemctl stop ceph-mds@ceph-server

Running Ceph with SysVinit

Each time you start, restart, or stop Ceph daemons, you must specify at least one option and one command. Likewise, each time you start, restart, or stop your entire cluster, you must specify at least one option and one command. In both cases, you can also specify a daemon type or a daemon instance.

{commandline} [options] [commands] [daemons]

The ceph options include:

Option

Shortcut

Description

--verbose

-v

Use verbose logging.

--valgrind

N/A

(Dev and QA only) Use Valgrind debugging.

--allhosts

-a

Execute on all nodes listed in ceph.conf. Otherwise, it only executes on localhost.

--restart

N/A

Automatically restart daemon if it core dumps.

--norestart

N/A

Do not restart a daemon if it core dumps.

--conf

-c

Use an alternate configuration file.

The ceph commands include:

Command

Description

start

Start the daemon(s).

stop

Stop the daemon(s).

forcestop

Force the daemon(s) to stop. Same as kill -9.

killall

Kill all daemons of a particular type.

cleanlogs

Cleans out the log directory.

cleanalllogs

Cleans out everything in the log directory.

The [daemons] option allows the ceph service to target specific daemon types in order to perform subsystem operations. Daemon types include:

  • mon

  • osd

  • mds

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