Chapter 2. Process Management

Each time you want to start, restart, and stop Ceph daemons or the entire cluster, you must specify at least one option and one command. 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.
`--allhosts`	`-a`	Execute on all nodes in the Ceph configuration. Otherwise, it only executes on `localhost`.
`--restart`	`N/A`	Automatically restart daemon if it core dumps.
`--norestart`	`N/A`	Don’t 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.

For subsystem operations, the ceph service can target specific daemon types by adding a particular daemon type for the [daemons] option. Daemon types include:

mon
osd

2.1. Running Ceph with System V Init

Using System V Init (sysvinit) is the common way to run Ceph with RHEL 7 for Red Hat Ceph Storage v1.3.

2.1.1. Starting All Daemons

To start your Ceph cluster, execute ceph with the start command. Use the following syntax:

sudo /etc/init.d/ceph [options] [start|restart] [daemonType|daemonID]

The following examples illustrates a typical use case:

sudo /etc/init.d/ceph -a start

Once you execute with -a (i.e., execute on all nodes), Ceph should begin operating.

2.1.2. Stopping All Daemons

To stop your Ceph cluster, execute ceph with the stop command. Use the following syntax:

sudo /etc/init.d/ceph [options] stop [daemonType|daemonID]

The following examples illustrates a typical use case:

sudo /etc/init.d/ceph -a stop

Once you execute with -a (i.e., execute on all nodes), Ceph should stop operating.

2.1.3. Starting All Daemons by Type

To start all Ceph daemons of a particular type on the local Ceph node, use the following syntax:

sudo /etc/init.d/ceph start {daemon-type}
sudo /etc/init.d/ceph start osd

To start all Ceph daemons of a particular type on another node, use the following syntax:

sudo /etc/init.d/ceph -a start {daemon-type}
sudo /etc/init.d/ceph -a start osd

2.1.4. Stopping All Daemons by Type

To stop all Ceph daemons of a particular type on the local Ceph node, use the following syntax:

sudo /etc/init.d/ceph stop {daemon-type}
sudo /etc/init.d/ceph stop osd

To stop all Ceph daemons of a particular type on another node, use the following syntax:

sudo /etc/init.d/ceph -a stop {daemon-type}
sudo /etc/init.d/ceph -a stop osd

2.1.5. Starting a Daemon by Instances

To start a Ceph daemon on the local Ceph node, use the following syntax:

sudo /etc/init.d/ceph start {daemon-type}.{instance}
sudo /etc/init.d/ceph start osd.0

To start a Ceph daemon on another node, use the following syntax:

sudo /etc/init.d/ceph -a start {daemon-type}.{instance}
sudo /etc/init.d/ceph -a start osd.0

2.1.6. Stopping a Daemon by Instances

To stop a Ceph daemon on the local Ceph node, use the following syntax:

sudo /etc/init.d/ceph stop {daemon-type}.{instance}
sudo /etc/init.d/ceph stop osd.0

To stop a Ceph daemon on another node, use the following syntax:

sudo /etc/init.d/ceph -a stop {daemon-type}.{instance}
sudo /etc/init.d/ceph -a stop osd.0

2.2. Running Ceph with Upstart

On Ubuntu 14.04 (Trusty), you can run Ceph using the event-based Upstart. Upstart does not require you to define daemon instances in the Ceph configuration file.

To list the Ceph Upstart jobs and instances on a node, execute:

sudo initctl list | grep ceph

See initctl for additional details.

2.2.1. Starting All Daemons

To start all daemons on a Ceph Node (irrespective of type), execute the following:

sudo start ceph-all

2.2.2. Stopping All Daemons

To stop all daemons on a Ceph Node (irrespective of type), execute the following:

sudo stop ceph-all

2.2.3. Starting All Daemons by Type

To start all daemons of a particular type on a Ceph Node, execute one of the following:

sudo start ceph-osd-all
sudo start ceph-mon-all
sudo start ceph-mds-all

2.2.4. Stopping All Daemons by Type

To stop all daemons of a particular type on a Ceph Node, execute one of the following:

sudo stop ceph-osd-all
sudo stop ceph-mon-all
sudo stop ceph-mds-all

2.2.5. Starting a Daemon by Instances

To start a specific daemon instance on a Ceph Node, execute one of the following:

sudo start ceph-osd id={id}
sudo start ceph-mon id={hostname}
sudo start ceph-mds id={hostname}

For example:

sudo start ceph-osd id=1
sudo start ceph-mon id=ceph-server
sudo start ceph-mds id=ceph-server

2.2.6. Stopping a Daemon by Instances

To stop a specific daemon instance on a Ceph Node, execute one of the following:

sudo stop ceph-osd id={id}
sudo stop ceph-mon id={hostname}
sudo stop ceph-mds id={hostname}

For example:

sudo stop ceph-osd id=1
sudo start ceph-mon id=ceph-server
sudo start ceph-mds id=ceph-server

2.3. Running Ceph as a Service

You may operate Ceph as a service.

2.3.1. Starting all Daemons

To start your Ceph cluster, execute ceph with the start command. Use the following syntax:

sudo service ceph [options] [start|restart] [daemonType|daemonID]

The following examples illustrates a typical use case:

sudo service ceph -a start

Once you execute with -a (i.e., execute on all nodes), Ceph should begin operating.

2.3.2. Stopping all Daemons

To stop your Ceph cluster, execute ceph with the stop command. Use the following syntax:

sudo service ceph [options] stop [daemonType|daemonID]

For example:

sudo service ceph -a stop

Once you execute with -a (i.e., execute on all nodes), Ceph should shut down.

2.3.3. Starting all Daemons by Type

To start all Ceph daemons of a particular type on the local Ceph node, use the following syntax:

sudo service ceph start {daemon-type}
sudo service ceph start osd

To start all Ceph daemons of a particular type on all nodes, use the following syntax:

sudo service ceph -a start {daemon-type}
sudo service ceph -a start osd

2.3.4. Stopping all Daemons by Type

To stop all Ceph daemons of a particular type on the local Ceph node, use the following syntax:

sudo service ceph stop {daemon-type}
sudo service ceph stop osd

To stop all Ceph daemons of a particular type on all nodes, use the following syntax:

sudo service ceph -a stop {daemon-type}
sudo service ceph -a stop osd

2.3.5. Starting a Daemon by Instances

To start a Ceph daemon on the local Ceph node, use the following syntax:

sudo service ceph start {daemon-type}.{instance}
sudo service ceph start osd.0

To start a Ceph daemon on another node, use the following syntax:

sudo service ceph -a start {daemon-type}.{instance}
sudo service ceph -a start osd.0

2.3.6. Stopping a Daemon by Instances

To stop a Ceph daemon on the local Ceph node, use the following syntax:

sudo service ceph stop {daemon-type}.{instance}
sudo service ceph stop osd.0

To stop a Ceph daemon on another node, use the following syntax:

sudo service ceph -a stop {daemon-type}.{instance}
sudo service ceph -a stop osd.0

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