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diff --git a/src/ceph/doc/dev/ceph-disk.rst b/src/ceph/doc/dev/ceph-disk.rst new file mode 100644 index 0000000..a4008aa --- /dev/null +++ b/src/ceph/doc/dev/ceph-disk.rst @@ -0,0 +1,61 @@ +========= +ceph-disk +========= + + +device-mapper crypt +=================== + +Settings +-------- + +``osd_dmcrypt_type`` + +:Description: this option specifies the mode in which ``cryptsetup`` works. It can be ``luks`` or ``plain``. It kicks in only if the ``--dmcrypt`` option is passed to ``ceph-disk``. See also `cryptsetup document <https://gitlab.com/cryptsetup/cryptsetup/wikis/DMCrypt#configuration-using-cryptsetup>`_ for more details. + +:Type: String +:Default: ``luks`` + + +``osd_dmcrypt_key_size`` + +:Description: the size of the random string in bytes used as the LUKS key. The string is read from ``/dev/urandom`` and then encoded using base64. It will be stored with the key of ``dm-crypt/osd/$uuid/luks`` using config-key. + +:Type: String +:Default: 1024 if ``osd_dmcrypt_type`` is ``luks``, 256 otherwise. + +lockbox +------- + +``ceph-disk`` supports dmcrypt (device-mapper crypt). If dmcrypt is enabled, the partitions will be encrypted using this machinary. For each OSD device, a lockbox is introduced for holding the information regarding how the dmcrypt key is stored. To prepare a lockbox, ``ceph-disk`` + +#. creates a dedicated lockbox partition on device, and +#. populates it with a tiny filesystem, then +#. automounts it at ``/var/lib/ceph/osd-lockbox/$uuid``, read-only. where the ``uuid`` is the lockbox's uuid. + +under which, settings are stored using plain files: + +- key-management-mode: ``ceph-mon v1`` +- osd-uuid: the OSD's uuid +- ceph_fsid: the fsid of the cluster +- keyring: the lockbox's allowing one to fetch the LUKS key +- block_uuid: the partition uuid for the block device +- journal_uuid: the partition uuid for the journal device +- block.db_uuid: the partition uuid for the block.db device +- block.wal_uuid: the partition uuid for the block.wal device +- magic: a magic string indicating that this partition is a lockbox. It's not used currently. +- ``${space_uuid}``: symbolic links named after the uuid of space partitions pointing to ``/var/lib/ceph/osd-lockbox/$uuid``. in the case of FileStore, the space partitions are ``data`` and ``journal`` partitions, for BlueStore, they are ``data``, ``block.db`` and ``block.wal``. + +Currently, ``ceph-mon v1`` is the only supported key-management-mode. In that case, the LUKS key is stored using the config-key in the monitor store with the key of ``dm-crypt/osd/$uuid/luks``. + + +partitions +========== + +``ceph-disk`` creates partitions for preparing a device for OSD deployment. Their partition numbers are hardcoded. For instance, data partition's partition number is always *1* : + +1. data partition +2. journal partition, if co-located with data +3. block.db for BlueStore, if co-located with data +4. block.wal for BlueStore, if co-located with data +5. lockbox |