============================================
Configuring the operating system and storage
============================================

This section describes the installation and configuration of operating
systems for the target hosts, as well as deploying SSH keys and
configuring storage.

Installing the operating system
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Install one of the following supported operating systems on the
target host:

* Ubuntu server 16.04 (Xenial Xerus) LTS 64-bit
* Centos 7 64-bit

Configure at least one network interface to access the Internet or
suitable local repositories.

We recommend adding the Secure Shell (SSH) server packages to the
installation on target hosts that do not have local (console) access.

.. note::

   We also recommend setting your locale to `en_US.UTF-8`. Other locales might
   work, but they are not tested or supported.

Configure the operating system (Ubuntu)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#. Update package source lists

   .. code-block:: shell-session

       # apt-get update

#. Upgrade the system packages and kernel:

   .. code-block:: shell-session

       # apt-get dist-upgrade

#. Reboot the host.

#. Ensure that the kernel version is ``3.13.0-34-generic`` or later:

   .. code-block:: shell-session

       # uname -r

#. Install additional software packages:

   .. code-block:: shell-session

       # apt-get install bridge-utils debootstrap ifenslave ifenslave-2.6 \
         lsof lvm2 ntp ntpdate openssh-server sudo tcpdump vlan

#. Add the appropriate kernel modules to the ``/etc/modules`` file to
   enable VLAN and bond interfaces:

   .. code-block:: shell-session

      # echo 'bonding' >> /etc/modules
      # echo '8021q' >> /etc/modules

#. Configure Network Time Protocol (NTP) in ``/etc/ntp.conf`` to
   synchronize with a suitable time source and restart the service:

   .. code-block:: shell-session

      # service ntp restart

#. Reboot the host to activate the changes and use the new kernel.

Configure the operating system (CentOS)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

#. Upgrade the system packages and kernel:

   .. code-block:: shell-session

       # yum upgrade

#. Reboot the host.

#. Ensure that the kernel version is ``3.10`` or later:

   .. code-block:: shell-session

       # uname -r

#. Install additional software packages:

   .. code-block:: shell-session

       # yum install bridge-utils iputils lsof lvm2 \
         ntp ntpdate openssh-server sudo tcpdump

#. Add the appropriate kernel modules to the ``/etc/modules`` file to
   enable VLAN and bond interfaces:

   .. code-block:: shell-session

      # echo 'bonding' >> /etc/modules-load.d/openstack-ansible.conf
      # echo '8021q' >> /etc/modules-load.d/openstack-ansible.conf

#. Configure Network Time Protocol (NTP) in ``/etc/ntp.conf`` to
   synchronize with a suitable time source and start the service:

   .. code-block:: shell-session

      # systemctl enable ntpd.service
      # systemctl start ntpd.service


#. Reboot the host to activate the changes and use the new kernel.

Deploying Secure Shell (SSH) keys
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Ansible uses SSH to connect the deployment host and target hosts.

#. Copy the contents of the public key file on the deployment host to
   the ``/root/.ssh/authorized_keys`` file on each target host.

#. Test public key authentication from the deployment host to each target
   host by using SSH to connect to the target host from the deployment host.
   If you can connect and get the shell without authenticating, it
   is working. SSH provides a shell without asking for a
   password.

For more information about how to generate an SSH key pair, as well as best
practices, see `GitHub's documentation about generating SSH keys`_.

.. _GitHub's documentation about generating SSH keys: https://help.github.com/articles/generating-ssh-keys/

.. important::

   OpenStack-Ansible deployments require the presence of a
   ``/root/.ssh/id_rsa.pub`` file on the deployment host.
   The contents of this file is inserted into an
   ``authorized_keys`` file for the containers, which is a
   necessary step for the Ansible playbooks. You can
   override this behavior by setting the
   ``lxc_container_ssh_key`` variable to the public key for
   the container.

.. _configuring-storage:

Configure storage
~~~~~~~~~~~~~~~~~

`Logical Volume Manager (LVM)`_ enables a single device to be split into
multiple logical volumes that appear as a physical storage device to the
operating system. The Block Storage (cinder) service, and the LXC containers
that run the OpenStack infrastructure, can optionally use LVM for their data
storage.

.. note::

   OpenStack-Ansible automatically configures LVM on the nodes, and
   overrides any existing LVM configuration. If you had a customized LVM
   configuration, edit the generated configuration file as needed.

#. To use the optional Block Storage (cinder) service, create an LVM
   volume group named ``cinder-volumes`` on the storage host. Specify a metadata
   size of 2048 when creating the physical volume. For example:

   .. code-block:: shell-session

       # pvcreate --metadatasize 2048 physical_volume_device_path
       # vgcreate cinder-volumes physical_volume_device_path

#. Optionally, create an LVM volume group named ``lxc`` for container file
   systems. If the ``lxc`` volume group does not exist, containers are
   automatically installed on the file system under ``/var/lib/lxc`` by
   default.

.. _Logical Volume Manager (LVM): https://en.wikipedia.org/wiki/Logical_Volume_Manager_(Linux)