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.
INTERACTIVE MODE
To start in interactive
mode, no arguments are necessary. Control-d or 'quit' will exit.
WATCH MODE
To watch cluster state changes in real time,
starting in -w (watch) mode will print updates to stdout as they occur. For example,
to keep an eye on cluster state,
ceph -C ceph.conf -w
COMMAND LINE MODE
Finally, to send a single instruction to the monitor cluster (and wait for a
response), the command can be specified on the command line.
OPTIONS
-i infile
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.
-o outfile
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.
-c ceph.conf, --conf=ceph.conf
Use ceph.conf configuration file instead of the default /etc/ceph/ceph.conf
to determine monitor addresses during startup.
-m monaddress[:port]
Connect to specified monitor (instead of looking through ceph.conf).
EXAMPLES
To grab a copy of the current OSD map:
ceph -m 1.2.3.4:6789 osd getmap -o osdmap
To get a dump of placement group (PG) state:
ceph pg dump -o pg.txt
MONITOR COMMANDS
A more complete summary of commands understood by the monitor cluster can be found
in the wiki, at