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Taikun OCP Guide

Table of Contents

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.

Note

The cinder volume service is named
openstack-cinder-volume on the following distributions:

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

In Ubuntu and Debian distributions, the cinder volume
service is named cinder-volume.

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.

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