pve-storage-rbd.adoc

   1 :fn-ceph-user-mgmt: footnote:cephusermgmt[Ceph user management {cephdocs-url}/rados/operations/user-management/]
   2 [[ceph_rados_block_devices]]
   3 Ceph RADOS Block Devices (RBD)
   4 ------------------------------
   5 ifdef::wiki[]
   6 :pve-toplevel:
   7 :title: Storage: RBD
   8 endif::wiki[]
   9
  10 Storage pool type: `rbd`
  11
  12 https://ceph.com[Ceph] is a distributed object store and file system
  13 designed to provide excellent performance, reliability and
  14 scalability. RADOS block devices implement a feature rich block level
  15 storage, and you get the following advantages:
  16
  17 * thin provisioning
  18 * resizable volumes
  19 * distributed and redundant (striped over multiple OSDs)
  20 * full snapshot and clone capabilities
  21 * self healing
  22 * no single point of failure
  23 * scalable to the exabyte level
  24 * kernel and user space implementation available
  25
  26 NOTE: For smaller deployments, it is also possible to run Ceph
  27 services directly on your {pve} nodes. Recent hardware has plenty
  28 of CPU power and RAM, so running storage services and VMs on same node
  29 is possible.
  30
  31 [[storage_rbd_config]]
  32 Configuration
  33 ~~~~~~~~~~~~~
  34
  35 This backend supports the common storage properties `nodes`,
  36 `disable`, `content`, and the following `rbd` specific properties:
  37
  38 monhost::
  39
  40 List of monitor daemon IPs. Optional, only needed if Ceph is not running on the
  41 {pve} cluster.
  42
  43 pool::
  44
  45 Ceph pool name.
  46
  47 username::
  48
  49 RBD user ID. Optional, only needed if Ceph is not running on the {pve} cluster.
  50 Note that only the user ID should be used. The "client." type prefix must be
  51 left out.
  52
  53 krbd::
  54
  55 Enforce access to rados block devices through the krbd kernel module. Optional.
  56
  57 NOTE: Containers will use `krbd` independent of the option value.
  58
  59 .Configuration Example for a external Ceph cluster (`/etc/pve/storage.cfg`)
  60 ----
  61 rbd: ceph-external
  62         monhost 10.1.1.20 10.1.1.21 10.1.1.22
  63         pool ceph-external
  64         content images
  65         username admin
  66 ----
  67
  68 TIP: You can use the `rbd` utility to do low-level management tasks.
  69
  70 Authentication
  71 ~~~~~~~~~~~~~~
  72
  73 NOTE: If Ceph is installed locally on the {pve} cluster, the following is done
  74 automatically when adding the storage.
  75
  76 If you use `cephx` authentication, which is enabled by default, you need to
  77 provide the keyring from the external Ceph cluster.
  78
  79 To configure the storage via the CLI, you first need to make the file
  80 containing the keyring available. One way is to copy the file from the external
  81 Ceph cluster directly to one of the {pve} nodes. The following example will
  82 copy it to the `/root` directory of the node on which we run it:
  83
  84 ----
  85 # scp <external cephserver>:/etc/ceph/ceph.client.admin.keyring /root/rbd.keyring
  86 ----
  87
  88 Then use the `pvesm` CLI tool to configure the external RBD storage, use the
  89 `--keyring` parameter, which needs to be a path to the keyring file that you
  90 copied.  For example:
  91
  92 ----
  93 # pvesm add rbd <name> --monhost "10.1.1.20 10.1.1.21 10.1.1.22" --content images --keyring /root/rbd.keyring
  94 ----
  95
  96 When configuring an external RBD storage via the GUI, you can copy and paste
  97 the keyring into the appropriate field.
  98
  99 The keyring will be stored at
 100
 101 ----
 102 # /etc/pve/priv/ceph/<STORAGE_ID>.keyring
 103 ----
 104
 105 TIP: Creating a keyring with only the needed capabilities is recommend when
 106 connecting to an external cluster. For further information on Ceph user
 107 management, see the Ceph docs.footnoteref:[cephusermgmt,{cephdocs-url}/rados/operations/user-management/[Ceph User Management]]
 108
 109 Ceph client configuration (optional)
 110 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 111
 112 Connecting to an external Ceph storage doesn't always allow setting
 113 client-specific options in the config DB on the external cluster. You can add a
 114 `ceph.conf` beside the Ceph keyring to change the Ceph client configuration for
 115 the storage.
 116
 117 The ceph.conf needs to have the same name as the storage.
 118
 119 ----
 120 # /etc/pve/priv/ceph/<STORAGE_ID>.conf
 121 ----
 122
 123 See the RBD configuration reference footnote:[RBD configuration reference
 124 {cephdocs-url}/rbd/rbd-config-ref/] for possible settings.
 125
 126 NOTE: Do not change these settings lightly. {PVE} is merging the
 127 <STORAGE_ID>.conf with the storage configuration.
 128
 129
 130 Storage Features
 131 ~~~~~~~~~~~~~~~~
 132
 133 The `rbd` backend is a block level storage, and implements full
 134 snapshot and clone functionality.
 135
 136 .Storage features for backend `rbd`
 137 [width="100%",cols="m,m,3*d",options="header"]
 138 |==============================================================================
 139 |Content types  |Image formats  |Shared |Snapshots |Clones
 140 |images rootdir |raw            |yes    |yes       |yes
 141 |==============================================================================
 142
 143 ifdef::wiki[]
 144
 145 See Also
 146 ~~~~~~~~
 147
 148 * link:/wiki/Storage[Storage]
 149
 150 endif::wiki[]
 151