ceph/doc/rbd/rbd-openstack.rst
Josh Durgin f0a5c562f5 doc: small fixes to the OpenStack page
* 'Ceph common' is not a package name
* config dir is /etc/nova, not /etc/conf
* remove trailing whitespace

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
2012-09-26 17:41:03 -07:00

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===================
RBD and OpenStack
===================
You may use Ceph block device images with OpenStack with QEMU and ``libvirt`` as
the interface. Ceph stripes block device images as objects across the cluster,
which means that large Ceph block device images have better performance than a
standalone server!
To use RBD with OpenStack, you must install QEMU, ``libvirt``, and OpenStack
first. We recommend using a separate physical host for your OpenStack
installation. OpenStack recommends a minimum of 8GB of RAM and a quad-core
processor. The following diagram depicts the OpenStack/Ceph technology stack.
.. ditaa:: +---------------------------------------------------+
| OpenStack |
+---------------------------------------------------+
| libvirt |
+---------------------------------------------------+
| QEMU/RBD |
+---------------------------------------------------+
| librbd |
+---------------------------------------------------+
| librados (C, C++, Java, Python, PHP, etc.) |
+------------------------+-+------------------------+
| OSDs | | Monitors |
+------------------------+ +------------------------+
.. _Installing OpenStack: ../../install/openstack
.. important:: To use RBD with OpenStack, you must have a running Ceph cluster.
Create a Pool
=============
By default, RBD uses the ``data`` pool. You may use any available RBD pool.
We recommend creating a pool for Nova. Ensure your Ceph cluster is running,
then create a pool. ::
ceph osd pool create nova
See `Create a Pool`_ for detail on specifying the number of placement groups
for your pool, and `Placement Groups`_ for details on the number of placement
groups you should set for your pool.
.. _Create a Pool: ../../cluster-ops/pools#createpool
.. _Placement Groups: ../../cluster-ops/placement-groups
Install Ceph Common on the OpenStack Host
=========================================
OpenStack operates as a Ceph client. You must install Ceph common on the
OpenStack host, and copy your Ceph cluster's ``ceph.conf`` file to the
``/etc/ceph`` directory. If you have installed Ceph on the host, ceph-common
is already included. ::
sudo apt-get install ceph-common
cd /etc/ceph
ssh your-openstack-server sudo tee /etc/ceph/ceph.conf <ceph.conf
Add the RBD Driver and the Pool Name to ``nova.conf``
=====================================================
OpenStack requires a driver to interact with RADOS block devices. You must also
specify the pool name for the block device. On your OpenStack host, navigate to
the ``/etc/nova`` directory. Open the ``nova.conf`` file in a text editor using
sudo privileges and add the following lines to the file::
volume_driver=nova.volume.driver.RBDDriver
rbd_pool=nova
Restart OpenStack
=================
To activate the RBD driver and load the RBD pool name into the configuration,
you must restart OpenStack. Navigate the directory where you installed
OpenStack, and execute the following::
./rejoin-stack.sh
If you have OpenStack configured as a service, you can also execute::
sudo service nova-volume restart
Once OpenStack is up and running, you should be able to create a volume with
OpenStack on a Ceph RADOS block device.