========================
Etcd for RHEL and CentOS
========================

OpenStack services may use Etcd, a distributed reliable key-value store
for distributed key locking, storing configuration, keeping track of service
live-ness and other scenarios.

The etcd service runs on the controller node.

Install and configure components
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#. Install the package:

   .. code-block:: console

      # yum install etcd

2. Edit the ``/etc/etcd/etcd.conf`` file and set the ``ETCD_INITIAL_CLUSTER``,
   ``ETCD_INITIAL_ADVERTISE_PEER_URLS``, ``ETCD_ADVERTISE_CLIENT_URLS``,
   ``ETCD_LISTEN_CLIENT_URLS`` to the management IP address of the controller
   node to enable access by other nodes via the management network:

   .. code-block:: ini

      #[Member]
      ETCD_DATA_DIR="/var/lib/etcd/default.etcd"
      ETCD_LISTEN_PEER_URLS="http://10.0.0.11:2380"
      ETCD_LISTEN_CLIENT_URLS="http://10.0.0.11:2379"
      ETCD_NAME="controller"
      #[Clustering]
      ETCD_INITIAL_ADVERTISE_PEER_URLS="http://10.0.0.11:2380"
      ETCD_ADVERTISE_CLIENT_URLS="http://10.0.0.11:2379"
      ETCD_INITIAL_CLUSTER="controller=http://10.0.0.11:2380"
      ETCD_INITIAL_CLUSTER_TOKEN="etcd-cluster-01"
      ETCD_INITIAL_CLUSTER_STATE="new"


Finalize installation
~~~~~~~~~~~~~~~~~~~~~

#. Enable and start the etcd service:

   .. code-block:: console

      # systemctl enable etcd
      # systemctl start etcd