ceph/doc/dev/config-key.rst

===================
 config-key layout
===================

*config-key* is a general-purpose key/value storage service offered by
the mons.  Generally speaking, you can put whatever you want there.
Current in-tree users should be captured here with their key layout
schema.

OSD dm-crypt keys
=================

Key::

  dm-crypt/osd/$OSD_UUID/luks = <json string>

The JSON payload has the form::

  { "dm-crypt": <secret> }

where the secret is a base64 encoded LUKS key.

Created by the 'osd new' command (see OSDMonitor.cc).

Consumed by ceph-volume, and similar tools. Normally access to the
dm-crypt/osd/$OSD_UUID prefix is allowed by a client.osd-lockbox.$OSD_UUID
cephx key, such that only the appropriate host can retrieve the LUKS key (which
in turn decrypts the actual raw key, also stored on the device itself).


ceph-mgr modules
================

The convention for keys is::

  mgr/$MODULE/$option = $value

or::

  mgr/$MODULE/$MGRID/$option = $value

For example,::

  mgr/dashboard/server_port = 80
  mgr/dashboard/foo/server_addr = 1.2.3.4
  mgr/dashboard/bar/server_addr = 1.2.3.5


Configuration
=============

Configuration options for clients and daemons are also stored in config-key.

Keys take the form::

  config/$option = $value
  config/$type/$option = $value
  config/$type.$id/$option = $value
  config/$type.$id/$mask[/$mask2...]/$option = $value

Where

* `type` is a daemon type (`osd`, `mon`, `mds`, `mgr`, `client`)
* `id` is a daemon id (e.g., `0`, `foo`), such that `$type.$id` is something like `osd.123` or `mds.foo`)
* `mask` restricts who the option applies to, and can take two forms:

  #. `$crush_type:$crush_value`.  For example, `rack:foorack`
  #. `class:$classname`, in reference to CRUSH device classes (e.g., `ssd`)