7 When Ceph services start, the initialization process activates a series
8 of daemons that run in the background. A :term:`Ceph Storage Cluster` runs
9 at a minimum three types of daemons:
11 - :term:`Ceph Monitor` (``ceph-mon``)
12 - :term:`Ceph Manager` (``ceph-mgr``)
13 - :term:`Ceph OSD Daemon` (``ceph-osd``)
15 Ceph Storage Clusters that support the :term:`Ceph File System` also run at
16 least one :term:`Ceph Metadata Server` (``ceph-mds``). Clusters that
17 support :term:`Ceph Object Storage` run Ceph RADOS Gateway daemons
18 (``radosgw``) as well.
20 Each daemon has a number of configuration options, each of which has a
21 default value. You may adjust the behavior of the system by changing these
22 configuration options. Be careful to understand the consequences before
23 overriding default values, as it is possible to significantly degrade the
24 performance and stability of your cluster. Also note that default values
25 sometimes change between releases, so it is best to review the version of
26 this documentation that aligns with your Ceph release.
31 All Ceph configuration options have a unique name consisting of words
32 formed with lower-case characters and connected with underscore
35 When option names are specified on the command line, either underscore
36 (``_``) or dash (``-``) characters can be used interchangeable (e.g.,
37 ``--mon-host`` is equivalent to ``--mon_host``).
39 When option names appear in configuration files, spaces can also be
40 used in place of underscore or dash. We suggest, though, that for
41 clarity and convenience you consistently use underscores, as we do
42 throughout this documentation.
47 Each Ceph daemon, process, and library will pull its configuration
48 from several sources, listed below. Sources later in the list will
49 override those earlier in the list when both are present.
51 - the compiled-in default value
52 - the monitor cluster's centralized configuration database
53 - a configuration file stored on the local host
54 - environment variables
55 - command line arguments
56 - runtime overrides set by an administrator
58 One of the first things a Ceph process does on startup is parse the
59 configuration options provided via the command line, environment, and
60 local configuration file. The process will then contact the monitor
61 cluster to retrieve configuration stored centrally for the entire
62 cluster. Once a complete view of the configuration is available, the
63 daemon or process startup will proceed.
65 .. _bootstrap-options:
70 Some configuration options affect the process's ability to contact the
71 monitors, to authenticate, and to retrieve the cluster-stored configuration.
72 For this reason, these options might need to be stored locally on the node, and
73 set by means of a local configuration file. These options include the
77 .. confval:: mon_host_override
79 - :confval:`mon_dns_srv_name`
80 - ``mon_data``, ``osd_data``, ``mds_data``, ``mgr_data``, and
81 similar options that define which local directory the daemon
83 - :confval:`keyring`, :confval:`keyfile`, and/or :confval:`key`, which can be used to
84 specify the authentication credential to use to authenticate with
85 the monitor. Note that in most cases the default keyring location
86 is in the data directory specified above.
88 In most cases, the default values of these options are suitable. There is one
89 exception to this: the :confval:`mon_host` option that identifies the addresses
90 of the cluster's monitors. When DNS is used to identify monitors, a local Ceph
91 configuration file can be avoided entirely.
93 Skipping monitor config
94 -----------------------
96 Pass the option ``--no-mon-config`` to any process to skip the step that
97 retrieves configuration information from the cluster monitors. This is useful
98 in cases where configuration is managed entirely via configuration files, or
99 when the monitor cluster is down and some maintenance activity needs to be
106 Configuration sections
107 ======================
109 Any given process or daemon has a single value for each configuration
110 option. However, values for an option may vary across different
111 daemon types even daemons of the same type. Ceph options that are
112 stored in the monitor configuration database or in local configuration
113 files are grouped into sections to indicate which daemons or clients
116 These sections include:
120 Settings under ``global`` affect all daemons and clients
121 in a Ceph Storage Cluster.
123 :example: ``log_file = /var/log/ceph/$cluster-$type.$id.log``
127 Settings under ``mon`` affect all ``ceph-mon`` daemons in
128 the Ceph Storage Cluster, and override the same setting in
131 :example: ``mon_cluster_log_to_syslog = true``
135 Settings in the ``mgr`` section affect all ``ceph-mgr`` daemons in
136 the Ceph Storage Cluster, and override the same setting in
139 :example: ``mgr_stats_period = 10``
143 Settings under ``osd`` affect all ``ceph-osd`` daemons in
144 the Ceph Storage Cluster, and override the same setting in
147 :example: ``osd_op_queue = wpq``
151 Settings in the ``mds`` section affect all ``ceph-mds`` daemons in
152 the Ceph Storage Cluster, and override the same setting in
155 :example: ``mds_cache_memory_limit = 10G``
159 Settings under ``client`` affect all Ceph Clients
160 (e.g., mounted Ceph File Systems, mounted Ceph Block Devices,
161 etc.) as well as Rados Gateway (RGW) daemons.
163 :example: ``objecter_inflight_ops = 512``
166 Sections may also specify an individual daemon or client name. For example,
167 ``mon.foo``, ``osd.123``, and ``client.smith`` are all valid section names.
170 Any given daemon will draw its settings from the global section, the
171 daemon or client type section, and the section sharing its name.
172 Settings in the most-specific section take precedence, so for example
173 if the same option is specified in both :confsec:`global`, :confsec:`mon`, and
174 ``mon.foo`` on the same source (i.e., in the same configurationfile),
175 the ``mon.foo`` value will be used.
177 If multiple values of the same configuration option are specified in the same
178 section, the last value wins.
180 Note that values from the local configuration file always take
181 precedence over values from the monitor configuration database,
182 regardless of which section they appear in.
185 .. _ceph-metavariables:
190 Metavariables simplify Ceph Storage Cluster configuration
191 dramatically. When a metavariable is set in a configuration value,
192 Ceph expands the metavariable into a concrete value at the time the
193 configuration value is used. Ceph metavariables are similar to variable expansion in the Bash shell.
195 Ceph supports the following metavariables:
197 .. describe:: $cluster
199 Expands to the Ceph Storage Cluster name. Useful when running
200 multiple Ceph Storage Clusters on the same hardware.
202 :example: ``/etc/ceph/$cluster.keyring``
207 Expands to a daemon or process type (e.g., ``mds``, ``osd``, or ``mon``)
209 :example: ``/var/lib/ceph/$type``
213 Expands to the daemon or client identifier. For
214 ``osd.0``, this would be ``0``; for ``mds.a``, it would
217 :example: ``/var/lib/ceph/$type/$cluster-$id``
221 Expands to the host name where the process is running.
225 Expands to ``$type.$id``.
227 :example: ``/var/run/ceph/$cluster-$name.asok``
231 Expands to daemon pid.
233 :example: ``/var/run/ceph/$cluster-$name-$pid.asok``
237 The Configuration File
238 ======================
240 On startup, Ceph processes search for a configuration file in the
243 #. ``$CEPH_CONF`` (*i.e.,* the path following the ``$CEPH_CONF``
244 environment variable)
245 #. ``-c path/path`` (*i.e.,* the ``-c`` command line argument)
246 #. ``/etc/ceph/$cluster.conf``
247 #. ``~/.ceph/$cluster.conf``
248 #. ``./$cluster.conf`` (*i.e.,* in the current working directory)
249 #. On FreeBSD systems only, ``/usr/local/etc/ceph/$cluster.conf``
251 where ``$cluster`` is the cluster's name (default ``ceph``).
253 The Ceph configuration file uses an *ini* style syntax. You can add comment
254 text after a pound sign (#) or a semi-colon (;). For example:
258 # <--A number (#) sign precedes a comment.
259 ; A comment may be anything.
260 # Comments always follow a semi-colon (;) or a pound (#) on each line.
261 # The end of the line terminates a comment.
262 # We recommend that you provide comments in your configuration file(s).
265 .. _ceph-conf-settings:
267 Config file section names
268 -------------------------
270 The configuration file is divided into sections. Each section must begin with a
271 valid configuration section name (see `Configuration sections`_, above)
272 surrounded by square brackets. For example,
289 Config file option values
290 -------------------------
292 The value of a configuration option is a string. If it is too long to
293 fit in a single line, you can put a backslash (``\``) at the end of line
294 as the line continuation marker, so the value of the option will be
295 the string after ``=`` in current line combined with the string in the next
302 In the example above, the value of "``foo``" would be "``long long ago long ago``".
304 Normally, the option value ends with a new line, or a comment, like
309 obscure_one = difficult to explain # I will try harder in next release
310 simpler_one = nothing to explain
312 In the example above, the value of "``obscure one``" would be "``difficult to explain``";
313 and the value of "``simpler one`` would be "``nothing to explain``".
315 If an option value contains spaces, and we want to make it explicit, we
316 could quote the value using single or double quotes, like
321 line = "to be, or not to be"
323 Certain characters are not allowed to be present in the option values directly.
324 They are ``=``, ``#``, ``;`` and ``[``. If we have to, we need to escape them,
330 secret = "i love \# and \["
332 Every configuration option is typed with one of the types below:
336 64-bit signed integer, Some SI prefixes are supported, like "K", "M", "G",
337 "T", "P", "E", meaning, respectively, 10\ :sup:`3`, 10\ :sup:`6`,
338 10\ :sup:`9`, etc. And "B" is the only supported unit. So, "1K", "1M", "128B" and "-1" are all valid
339 option values. Some times, a negative value implies "unlimited" when it comes to
340 an option for threshold or limit.
342 :example: ``42``, ``-1``
346 It is almost identical to ``integer``. But a negative value will be rejected.
348 :example: ``256``, ``0``
352 Free style strings encoded in UTF-8, but some characters are not allowed. Please
353 reference the above notes for the details.
355 :example: ``"hello world"``, ``"i love \#"``, ``yet-another-name``
357 .. describe:: boolean
359 one of the two values ``true`` or ``false``. But an integer is also accepted,
360 where "0" implies ``false``, and any non-zero values imply ``true``.
362 :example: ``true``, ``false``, ``1``, ``0``
366 a single address optionally prefixed with ``v1``, ``v2`` or ``any`` for the messenger
367 protocol. If the prefix is not specified, ``v2`` protocol is used. Please see
368 :ref:`address_formats` for more details.
370 :example: ``v1:1.2.3.4:567``, ``v2:1.2.3.4:567``, ``1.2.3.4:567``, ``2409:8a1e:8fb6:aa20:1260:4bff:fe92:18f5::567``, ``[::1]:6789``
372 .. describe:: addrvec
374 a set of addresses separated by ",". The addresses can be optionally quoted with ``[`` and ``]``.
376 :example: ``[v1:1.2.3.4:567,v2:1.2.3.4:568]``, ``v1:1.2.3.4:567,v1:1.2.3.14:567`` ``[2409:8a1e:8fb6:aa20:1260:4bff:fe92:18f5::567], [2409:8a1e:8fb6:aa20:1260:4bff:fe92:18f5::568]``
380 the string format of a uuid defined by `RFC4122 <https://www.ietf.org/rfc/rfc4122.txt>`_.
381 And some variants are also supported, for more details, see
382 `Boost document <https://www.boost.org/doc/libs/1_74_0/libs/uuid/doc/uuid.html#String%20Generator>`_.
384 :example: ``f81d4fae-7dec-11d0-a765-00a0c91e6bf6``
388 denotes a 64-bit unsigned integer. Both SI prefixes and IEC prefixes are
389 supported. And "B" is the only supported unit. A negative value will be
392 :example: ``1Ki``, ``1K``, ``1KiB`` and ``1B``.
396 denotes a duration of time. By default the unit is second if not specified.
397 Following units of time are supported:
399 * second: "s", "sec", "second", "seconds"
400 * minute: "m", "min", "minute", "minutes"
401 * hour: "hs", "hr", "hour", "hours"
402 * day: "d", "day", "days"
403 * week: "w", "wk", "week", "weeks"
404 * month: "mo", "month", "months"
405 * year: "y", "yr", "year", "years"
407 :example: ``1 m``, ``1m`` and ``1 week``
409 .. _ceph-conf-database:
411 Monitor configuration database
412 ==============================
414 The monitor cluster manages a database of configuration options that
415 can be consumed by the entire cluster, enabling streamlined central
416 configuration management for the entire system. The vast majority of
417 configuration options can and should be stored here for ease of
418 administration and transparency.
420 A handful of settings may still need to be stored in local
421 configuration files because they affect the ability to connect to the
422 monitors, authenticate, and fetch configuration information. In most
423 cases this is limited to the ``mon_host`` option, although this can
424 also be avoided through the use of DNS SRV records.
429 Configuration options stored by the monitor can live in a global
430 section, daemon type section, or specific daemon section, just like
431 options in a configuration file can.
433 In addition, options may also have a *mask* associated with them to
434 further restrict which daemons or clients the option applies to.
435 Masks take two forms:
437 #. ``type:location`` where *type* is a CRUSH property like `rack` or
438 `host`, and *location* is a value for that property. For example,
439 ``host:foo`` would limit the option only to daemons or clients
440 running on a particular host.
441 #. ``class:device-class`` where *device-class* is the name of a CRUSH
442 device class (e.g., ``hdd`` or ``ssd``). For example,
443 ``class:ssd`` would limit the option only to OSDs backed by SSDs.
444 (This mask has no effect for non-OSD daemons or clients.)
446 When setting a configuration option, the `who` may be a section name,
447 a mask, or a combination of both separated by a slash (``/``)
448 character. For example, ``osd/rack:foo`` would mean all OSD daemons
451 When viewing configuration options, the section name and mask are
452 generally separated out into separate fields or columns to ease readability.
458 The following CLI commands are used to configure the cluster:
460 * ``ceph config dump`` will dump the entire configuration database for
463 * ``ceph config get <who>`` will dump the configuration for a specific
464 daemon or client (e.g., ``mds.a``), as stored in the monitors'
465 configuration database.
467 * ``ceph config set <who> <option> <value>`` will set a configuration
468 option in the monitors' configuration database.
470 * ``ceph config show <who>`` will show the reported running
471 configuration for a running daemon. These settings may differ from
472 those stored by the monitors if there are also local configuration
473 files in use or options have been overridden on the command line or
474 at run time. The source of the option values is reported as part
477 * ``ceph config assimilate-conf -i <input file> -o <output file>``
478 will ingest a configuration file from *input file* and move any
479 valid options into the monitors' configuration database. Any
480 settings that are unrecognized, invalid, or cannot be controlled by
481 the monitor will be returned in an abbreviated config file stored in
482 *output file*. This command is useful for transitioning from legacy
483 configuration files to centralized monitor-based configuration.
489 You can get help for a particular option with:
493 ceph config help <option>
495 Note that this will use the configuration schema that is compiled into the running monitors. If you have a mixed-version cluster (e.g., during an upgrade), you might also want to query the option schema from a specific running daemon:
499 ceph daemon <name> config help [option]
505 ceph config help log_file
509 log_file - path to log file
511 Default (non-daemon):
512 Default (daemon): /var/log/ceph/$cluster-$name.log
513 Can update at runtime: false
514 See also: [log_to_stderr,err_to_stderr,log_to_syslog,err_to_syslog]
520 ceph config help log_file -f json-pretty
526 "type": "std::string",
528 "desc": "path to log file",
531 "daemon_default": "/var/log/ceph/$cluster-$name.log",
543 "can_update_at_runtime": false
546 The ``level`` property can be any of `basic`, `advanced`, or `dev`.
547 The `dev` options are intended for use by developers, generally for
548 testing purposes, and are not recommended for use by operators.
554 In most cases, Ceph permits changes to the configuration of a daemon at
555 runtime. This can be used for increasing or decreasing the amount of logging
556 output, for enabling or disabling debug settings, and for runtime optimization.
558 Configuration options can be updated via the ``ceph config set`` command. For
559 example, to enable the debug log level on a specific OSD, run a command of this form:
563 ceph config set osd.123 debug_ms 20
565 .. note:: If an option has been customized in a local configuration file, the
567 <https://ceph.io/en/news/blog/2018/new-mimic-centralized-configuration-management/>`_
568 setting will be ignored (it has a lower priority than the local
574 Options can be set temporarily by using the `tell` or `daemon` interfaces on
575 the Ceph CLI. These *override* values are ephemeral, which means that they
576 affect only the current instance of the daemon and revert to persistently
577 configured values when the daemon restarts.
579 Override values can be set in two ways:
581 #. From any host, send a message to a daemon with a command of the following
586 ceph tell <name> config set <option> <value>
592 ceph tell osd.123 config set debug_osd 20
594 The ``tell`` command can also accept a wildcard as the daemon identifier.
595 For example, to adjust the debug level on all OSD daemons, run a command of
600 ceph tell osd.* config set debug_osd 20
602 #. On the host where the daemon is running, connect to the daemon via a socket
603 in ``/var/run/ceph`` by running a command of this form:
607 ceph daemon <name> config set <option> <value>
613 ceph daemon osd.4 config set debug_osd 20
615 .. note:: In the output of the ``ceph config show`` command, these temporary
616 values are shown with a source of ``override``.
619 Viewing runtime settings
620 ========================
622 You can see the current options set for a running daemon with the ``ceph config show`` command. For example:
626 ceph config show osd.0
628 will show you the (non-default) options for that daemon. You can also look at a specific option with:
632 ceph config show osd.0 debug_osd
634 or view all options (even those with default values) with:
638 ceph config show-with-defaults osd.0
640 You can also observe settings for a running daemon by connecting to it from the local host via the admin socket. For example:
644 ceph daemon osd.0 config show
646 will dump all current settings:
650 ceph daemon osd.0 config diff
652 will show only non-default settings (as well as where the value came from: a config file, the monitor, an override, etc.), and:
656 ceph daemon osd.0 config get debug_osd
658 will report the value of a single option.
662 Changes since Nautilus
663 ======================
665 With the Octopus release We changed the way the configuration file is parsed.
666 These changes are as follows:
668 - Repeated configuration options are allowed, and no warnings will be printed.
669 The value of the last one is used, which means that the setting last in the file
670 is the one that takes effect. Before this change, we would print warning messages
671 when lines with duplicated options were encountered, like::
673 warning line 42: 'foo' in section 'bar' redefined
675 - Invalid UTF-8 options were ignored with warning messages. But since Octopus,
676 they are treated as fatal errors.
678 - Backslash ``\`` is used as the line continuation marker to combine the next
679 line with current one. Before Octopus, it was required to follow a backslash with
680 a non-empty line. But in Octopus, an empty line following a backslash is now allowed.
682 - In the configuration file, each line specifies an individual configuration
683 option. The option's name and its value are separated with ``=``, and the
684 value may be quoted using single or double quotes. If an invalid
685 configuration is specified, we will treat it as an invalid configuration
688 bad option ==== bad value
690 - Before Octopus, if no section name was specified in the configuration file,
691 all options would be set as though they were within the :confsec:`global` section. This is
692 now discouraged. Since Octopus, only a single option is allowed for
693 configuration files without a section name.