.. index:: control, commands

=================
 Control commands
=================

Monitor commands
----------------

Monitor commands are issued using the ceph utility (in versions before
Dec08 it was called cmonctl)::

	$ ceph [-m monhost] command

where the command is usually of the form::

	$ ceph subsystem command

System commands
---------------

::

	$ ceph stop

Cleanly shuts down the cluster.  ::

	$ ceph -s

Shows an overview of the current status of the cluster.  ::

	$ ceph -w

Shows a running summary of the status of the cluster, and major events.

AUTH subsystem
--------------
::

	$ ceph auth add <osd> <--in-file|-i> <path-to-osd-keyring>

Add auth keyring for an osd.  ::

	$ ceph auth list

Show auth key OSD subsystem.

OSD subsystem
-------------
::

	$ ceph osd stat

Query osd subsystem status. ::

	$ ceph osd getmap -o file

Write a copy of the most recent osd map to a file. See
:doc:`osdmaptool </man/8/osdmaptool>`. ::

	$ ceph osd getcrushmap -o file

Write a copy of the crush map from the most recent osd map to
file. This is functionally equivalent to ::

	$ ceph osd getmap -o /tmp/osdmap
	$ osdmaptool /tmp/osdmap --export-crush file

::

	$ ceph osd dump [--format <format>]

Dump the osd map. Valid formats for -f are "plain" and "json". If no
--format option is given, the osd map is dumped as plain text. ::

	$ ceph osd tree [--format <format>]

Dump the osd map as a tree with one line per osd containing weight
and state. ::

	$ ceph osd crush add <id> <name> <weight> [<loc1> [<loc2> ...]]

Add a new item with the given id/name/weight at the specified
location. ::

	$ ceph osd crush remove <id>

Remove an existing item from the crush map. ::

	$ ceph osd crush reweight <name> <weight>

Set the weight of the item given by ``<name>`` to ``<weight>``. ::

	$ ceph osd cluster_snap <name>

Create a cluster snapshot. ::

	$ ceph osd lost [--yes-i-really-mean-it]

Mark an OSD as lost. This may result in permanent data loss. Use with caution. ::

	$ ceph osd create [<id>]

Create a new OSD. If no ID is given, a new ID is automatically selected
if possible. ::

	$ ceph osd rm [<id>...]

Remove the given OSD(s). ::

	$ ceph osd getmaxosd

Query the current max_osd parameter in the osd map. ::

	$ ceph osd setmap -i file

Import the given osd map. Note that this can be a bit dangerous,
since the osd map includes dynamic state about which OSDs are current
on or offline; only do this if you've just modified a (very) recent
copy of the map. ::

	$ ceph osd setcrushmap -i file

Import the given crush map. ::

	$ ceph osd setmaxosd

Set the max_osd parameter in the osd map. This is necessary when
expanding the storage cluster. ::

	$ ceph osd down N

Mark osdN down. ::

	$ ceph osd out N

Mark osdN out of the distribution (i.e. allocated no data). ::

	$ ceph osd in N

Mark osdN in the distribution (i.e. allocated data). ::

	$ ceph class list

List classes that are loaded in the ceph cluster. ::

	$ ceph osd pause
	$ ceph osd unpause

Set or clear the pause flags in the OSD map. If set, no IO requests
will be sent to any OSD. Clearing the flags via unpause results in
resending pending requests. ::

	$ ceph osd reweight N W

Set the weight of osdN to W. Two OSDs with the same weight will receive
roughly the same number of I/O requests and store approximately the
same amount of data. ::

	$ ceph osd reweight-by-utilization [threshold]

Reweights all the OSDs by reducing the weight of OSDs which are
heavily overused. By default it will adjust the weights downward on
OSDs which have 120% of the average utilization, but if you include
threshold it will use that percentage instead. ::

	$ ceph osd blacklist add ADDRESS[:source_port] [TIME]
	$ ceph osd blacklist rm ADDRESS[:source_port]

Adds/removes the address to/from the blacklist. When adding an address,
you can specify how long it should be blacklisted in seconds; otherwise
it will default to 1 hour. A blacklisted address is prevented from
connecting to any osd. Blacklisting is most often used to prevent a
laggy mds making bad changes to data on the osds.

These commands are mostly only useful for failure testing, as
blacklists are normally maintained automatically and shouldn't need
manual intervention. ::

	$ ceph osd pool mksnap POOL SNAPNAME
	$ ceph osd pool rmsnap POOL SNAPNAME

Creates/deletes a snapshot of a pool. ::

	$ ceph osd pool create POOL
	$ ceph osd pool delete POOL

Creates/deletes a storage pool. ::

	$ ceph osd pool set POOL FIELD VALUE

Changes a pool setting. Valid fields are:

	* ``size``: Sets the number of copies of data in the pool.
	* ``crash_replay_interval``: The number of seconds to allow
	  clients to replay acknowledged but uncommited requests.
	* ``pg_num``: The placement group number.
	* ``pgp_num``: Effective number when calculating pg placement.
	* ``crush_ruleset``: rule number for mapping placement.

::

	$ ceph osd pool get POOL FIELD

Get the value of a pool setting. Valid fields are:

	* ``pg_num``: See above.
	* ``pgp_num``: See above.
	* ``lpg_num``: The number of local PGs.
	* ``lpgp_num``: The number used for placing the local PGs.

::

	$ ceph osd scrub N

Sends a scrub command to osdN. To send the command to all osds, use ``*``.
TODO: what does this actually do ::

	$ ceph osd repair N

Sends a repair command to osdN. To send the command to all osds, use ``*``.
TODO: what does this actually do

MDS subsystem
-------------

Change configuration parameters on a running mds. ::

	$ ceph mds tell <mds-id> injectargs '--<switch> <value> [--<switch> <value>]'

Example::

	$ ceph mds tell 0 injectargs '--debug_ms 1 --debug_mds 10'

Enables debug messages. ::

	$ ceph mds stat

Displays the status of all metadata servers.

.. todo:: ``ceph mds`` subcommands missing docs: set_max_mds, dump, getmap, stop, setmap