Configure an NFS storage back end

This section explains how to configure OpenStack Block Storage to use
NFS storage. You must be able to access the NFS shares from the server
that hosts the cinder volume service.

Configure Block Storage to use an NFS storage back
end

1. Log in as root to the system hosting the
   cinder volume service.

2. Create a text file named nfs_shares in the
   /etc/cinder/ directory.

3. Add an entry to /etc/cinder/nfs_shares for each NFS
   share that the cinder volume service should use for back
   end storage. Each entry should be a separate line, and should use the
   following format:

   HOST:SHARE

   Where:

   • HOST is the IP address or host name of the NFS server.
   • SHARE is the absolute path to an existing and accessible NFS
     share.

4. Set /etc/cinder/nfs_shares to be owned by the
   root user and the cinder group:

   # chown root:cinder /etc/cinder/nfs_shares

5. Set /etc/cinder/nfs_shares to be readable by members
   of the cinder group:

   # chmod 0640 /etc/cinder/nfs_shares

6. Configure the cinder volume service to use the
   /etc/cinder/nfs_shares file created earlier. To do so, open
   the /etc/cinder/cinder.conf configuration file and set the
   nfs_shares_config configuration key to
   /etc/cinder/nfs_shares.

   On distributions that include openstack-config, you can
   configure this by running the following command instead:

   # openstack-config --set /etc/cinder/cinder.conf \
     DEFAULT nfs_shares_config /etc/cinder/nfs_shares

   The following distributions include openstack-config:

   • CentOS
   • Fedora
   • openSUSE
   • Red Hat Enterprise Linux
   • SUSE Linux Enterprise

7. Optionally, provide any additional NFS mount options required in
   your environment in the nfs_mount_options configuration key
   of /etc/cinder/cinder.conf. If your NFS shares do not
   require any additional mount options (or if you are unsure), skip this
   step.

   On distributions that include openstack-config, you can
   configure this by running the following command instead:

   # openstack-config --set /etc/cinder/cinder.conf \
     DEFAULT nfs_mount_options OPTIONS

   Replace OPTIONS with the mount options to be used when accessing NFS
   shares. See the manual page for NFS for more information on available
   mount options (man nfs).

8. Configure the cinder volume service to use the
   correct volume driver, namely
   cinder.volume.drivers.nfs.NfsDriver. To do so, open the
   /etc/cinder/cinder.conf configuration file and set the
   volume_driver configuration key to
   cinder.volume.drivers.nfs.NfsDriver.

   On distributions that include openstack-config, you can
   configure this by running the following command instead:

   # openstack-config --set /etc/cinder/cinder.conf \
     DEFAULT volume_driver cinder.volume.drivers.nfs.NfsDriver

9. You can now restart the service to apply the configuration.

   Note

   The nfs_sparsed_volumes configuration key determines
   whether volumes are created as sparse files and grown as needed or fully
   allocated up front. The default and recommended value is
   true, which ensures volumes are initially created as sparse
   files.

   Setting nfs_sparsed_volumes to false will
   result in volumes being fully allocated at the time of creation. This
   leads to increased delays in volume creation.

   However, should you choose to set nfs_sparsed_volumes to
   false, you can do so directly in
   /etc/cinder/cinder.conf.

   On distributions that include openstack-config, you can
   configure this by running the following command instead:

   # openstack-config --set /etc/cinder/cinder.conf \
     DEFAULT nfs_sparsed_volumes false

   Warning

   If a client host has SELinux enabled, the virt_use_nfs
   boolean should also be enabled if the host requires access to NFS
   volumes on an instance. To enable this boolean, run the following
   command as the root user:

   # setsebool -P virt_use_nfs on

   This command also makes the boolean persistent across reboots. Run
   this command on all client hosts that require access to NFS volumes on
   an instance. This includes all compute nodes.