Synnefo » snf-ganeti » ganeti-local

If you choose to use RBD-based instances, there's no need for LVM

provisioning. However, this feature is experimental, and is not

recommended for production clusters.

Installing RBD

+++++++++++++++

Recommended on all nodes: RBD_ is required if you want to create

instances with RBD disks residing inside a RADOS cluster (make use of

the rbd disk template). RBD-based instances can failover or migrate to

any other node in the ganeti cluster, enabling you to exploit of all

Ganeti's high availabilily (HA) features.

.. attention::

   Be careful though: rbd is still experimental! For now it is

   recommended only for testing purposes.  No sensitive data should be

   stored there.

.. _RBD: http://ceph.newdream.net/

You will need the ``rbd`` and ``libceph`` kernel modules, the RBD/Ceph

userspace utils (ceph-common Debian package) and an appropriate

Ceph/RADOS configuration file on every VM-capable node.

You will also need a working RADOS Cluster accessible by the above

nodes.

RADOS Cluster

~~~~~~~~~~~~~

You will need a working RADOS Cluster accesible by all VM-capable nodes

to use the RBD template. For more information on setting up a RADOS

Cluster, refer to the `official docs <http://ceph.newdream.net/>`_.

If you want to use a pool for storing RBD disk images other than the

default (``rbd``), you should first create the pool in the RADOS

Cluster, and then set the corresponding rbd disk parameter named

``pool``.

Kernel Modules

~~~~~~~~~~~~~~

Unless your distribution already provides it, you might need to compile

the ``rbd`` and ``libceph`` modules from source. You will need Linux

Kernel 3.2 or above for the kernel modules. Alternatively you will have

to build them as external modules (from Linux Kernel source 3.2 or

above), if you want to run a less recent kernel, or your kernel doesn't

include them.

Userspace Utils

~~~~~~~~~~~~~~~

The RBD template has been tested with ``ceph-common`` v0.38 and

above. We recommend using the latest version of ``ceph-common``.

.. admonition:: Debian

   On Debian, you can just install the RBD/Ceph userspace utils with

   the following command::

      apt-get install ceph-common

Configuration file

~~~~~~~~~~~~~~~~~~

You should also provide an appropriate configuration file

(``ceph.conf``) in ``/etc/ceph``. For the rbd userspace utils, you'll

only need to specify the IP addresses of the RADOS Cluster monitors.

.. admonition:: ceph.conf

   Sample configuration file::

    [mon.a]

           host = example_monitor_host1

           mon addr = 1.2.3.4:6789

    [mon.b]

           host = example_monitor_host2

           mon addr = 1.2.3.5:6789

    [mon.c]

           host = example_monitor_host3

           mon addr = 1.2.3.6:6789

For more information, please see the `Ceph Docs

<http://ceph.newdream.net/docs/latest/>`_