ceph/doc/dev/ceph-volume/lvm.rst

   1
   2 .. _ceph-volume-lvm-api:
   3
   4 LVM
   5 ===
   6 The backend of ``ceph-volume lvm`` is LVM, it relies heavily on the usage of
   7 tags, which is a way for LVM to allow extending its volume metadata. These
   8 values can later be queried against devices and it is how they get discovered
   9 later.
  10
  11 .. warning:: These APIs are not meant to be public, but are documented so that
  12              it is clear what the tool is doing behind the scenes. Do not alter
  13              any of these values.
  14
  15
  16 .. _ceph-volume-lvm-tag-api:
  17
  18 Tag API
  19 -------
  20 The process of identifying logical volumes as part of Ceph relies on applying
  21 tags on all volumes. It follows a naming convention for the namespace that
  22 looks like::
  23
  24     ceph.<tag name>=<tag value>
  25
  26 All tags are prefixed by the ``ceph`` keyword to claim ownership of that
  27 namespace and make it easily identifiable. This is how the OSD ID would be used
  28 in the context of lvm tags::
  29
  30     ceph.osd_id=0
  31
  32
  33 .. _ceph-volume-lvm-tags:
  34
  35 Metadata
  36 --------
  37 The following describes all the metadata from Ceph OSDs that is stored on an
  38 LVM volume:
  39
  40
  41 ``type``
  42 --------
  43 Describes if the device is a an OSD or Journal, with the ability to expand to
  44 other types when supported (for example a lockbox)
  45
  46 Example::
  47
  48     ceph.type=osd
  49
  50
  51 ``cluster_fsid``
  52 ----------------
  53 Example::
  54
  55     ceph.cluster_fsid=7146B649-AE00-4157-9F5D-1DBFF1D52C26
  56
  57
  58 ``data_device``
  59 ---------------
  60 Example::
  61
  62     ceph.data_device=/dev/ceph/data-0
  63
  64
  65 ``data_uuid``
  66 -------------
  67 Example::
  68
  69     ceph.data_uuid=B76418EB-0024-401C-8955-AE6919D45CC3
  70
  71
  72 ``journal_device``
  73 ------------------
  74 Example::
  75
  76     ceph.journal_device=/dev/ceph/journal-0
  77
  78
  79 ``journal_uuid``
  80 ----------------
  81 Example::
  82
  83     ceph.journal_uuid=2070E121-C544-4F40-9571-0B7F35C6CB2B
  84
  85
  86 ``encrypted``
  87 -------------
  88 Example for enabled encryption with ``luks``::
  89
  90     ceph.encrypted=1
  91
  92 When encryption is not supported or simply disabled::
  93
  94     ceph.encrypted=0
  95
  96
  97 ``osd_fsid``
  98 ------------
  99 Example::
 100
 101     ceph.osd_fsid=88ab9018-f84b-4d62-90b4-ce7c076728ff
 102
 103
 104 ``osd_id``
 105 ----------
 106 Example::
 107
 108     ceph.osd_id=1
 109
 110
 111 ``block_device``
 112 ----------------
 113 Just used on :term:`bluestore` backends. Captures the path to the logical
 114 volume path.
 115
 116 Example::
 117
 118     ceph.block_device=/dev/mapper/vg-block-0
 119
 120
 121 ``block_uuid``
 122 --------------
 123 Just used on :term:`bluestore` backends. Captures either the logical volume UUID or
 124 the partition UUID.
 125
 126 Example::
 127
 128     ceph.block_uuid=E5F041BB-AAD4-48A8-B3BF-31F7AFD7D73E
 129
 130
 131 ``db_device``
 132 -------------
 133 Just used on :term:`bluestore` backends. Captures the path to the logical
 134 volume path.
 135
 136 Example::
 137
 138     ceph.db_device=/dev/mapper/vg-db-0
 139
 140
 141 ``db_uuid``
 142 -----------
 143 Just used on :term:`bluestore` backends. Captures either the logical volume UUID or
 144 the partition UUID.
 145
 146 Example::
 147
 148     ceph.db_uuid=F9D02CF1-31AB-4910-90A3-6A6302375525
 149
 150
 151 ``wal_device``
 152 --------------
 153 Just used on :term:`bluestore` backends. Captures the path to the logical
 154 volume path.
 155
 156 Example::
 157
 158     ceph.wal_device=/dev/mapper/vg-wal-0
 159
 160
 161 ``wal_uuid``
 162 ------------
 163 Just used on :term:`bluestore` backends. Captures either the logical volume UUID or
 164 the partition UUID.
 165
 166 Example::
 167
 168     ceph.wal_uuid=A58D1C68-0D6E-4CB3-8E99-B261AD47CC39