ceph is a control utility for communicating with the monitor cluster of a running Ceph distributed file system.
There are three basic modes of operation.
To start in interactive mode, no arguments are necessary. Control-d or ‘quit’ will exit.
Watch mode shows cluster state changes as they occur. For example:
Finally, to send a single instruction to the monitor cluster (and wait for a response), the command can be specified on the command line.
will specify an input file to be passed along as a payload with the command to the monitor cluster. This is only used for specific monitor commands.
will write any payload returned by the monitor cluster with its reply to outfile. Only specific monitor commands (e.g. osd getmap) return a payload.
Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf to determine monitor addresses during startup.
Connect to specified monitor (instead of looking through ceph.conf).
To grab a copy of the current OSD map:
ceph -m 188.8.131.52:6789 osd getmap -o osdmap
To get a dump of placement group (PG) state:
ceph pg dump -o pg.txt
A more complete summary of commands understood by the monitor cluster can be found in the online documentation, at
ceph is part of the Ceph distributed file system. Please refer to the Ceph documentation at http://ceph.com/docs for more information.