ac477b8f7b
Change all remaining occurences to speak only about Installation Guides. Change-Id: Ie590d35bd4b68152a64f0a7e2dda6aa0b250a1b1
33 lines
1.4 KiB
ReStructuredText
33 lines
1.4 KiB
ReStructuredText
====================
|
|
Installing Memcached
|
|
====================
|
|
|
|
Most OpenStack services can use Memcached to store ephemeral data such as
|
|
tokens. Although Memcached does not support typical forms of redundancy such
|
|
as clustering, OpenStack services can use almost any number of instances
|
|
by configuring multiple hostnames or IP addresses.
|
|
|
|
The Memcached client implements hashing to balance objects among the instances.
|
|
Failure of an instance only impacts a percentage of the objects,
|
|
and the client automatically removes it from the list of instances.
|
|
|
|
To install and configure Memcached, read the
|
|
`official documentation <https://github.com/Memcached/Memcached/wiki#getting-started>`_.
|
|
|
|
Memory caching is managed by `oslo.cache
|
|
<http://specs.openstack.org/openstack/oslo-specs/specs/kilo/oslo-cache-using-dogpile.html>`_.
|
|
This ensures consistency across all projects when using multiple Memcached
|
|
servers. The following is an example configuration with three hosts:
|
|
|
|
.. code-block:: ini
|
|
|
|
Memcached_servers = controller1:11211,controller2:11211,controller3:11211
|
|
|
|
By default, ``controller1`` handles the caching service. If the host goes down,
|
|
``controller2`` or ``controller3`` will complete the service.
|
|
|
|
For more information about Memcached installation, see the
|
|
*Environment -> Memcached* section in the
|
|
`Installation Guides <https://docs.openstack.org/ocata/install/>`_
|
|
depending on your distribution.
|