OpenStack ManualsOpenStack Cloud Administrator Guide  - current

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 Configure a GlusterFS back end

This section explains how to configure OpenStack Block Storage to use GlusterFS as a back end. You must be able to access the GlusterFS shares from the server that hosts the cinder volume service.

[Note]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.

Mounting GlusterFS volumes requires utilities and libraries from the glusterfs-fuse package. This package must be installed on all systems that will access volumes backed by GlusterFS.

[Note]Note

The utilities and libraries required for mounting GlusterFS volumes on Ubuntu and Debian distributions are available from the glusterfs-client package instead.

For information on how to install and configure GlusterFS, refer to the GlusterDocumentation page.

 

Procedure 6.2. Configure GlusterFS for OpenStack Block Storage

The GlusterFS server must also be configured accordingly in order to allow OpenStack Block Storage to use GlusterFS shares:

  1. Log in as root to the GlusterFS server.

  2. Set each Gluster volume to use the same UID and GID as the cinder user: 

    # gluster volume set VOL_NAME storage.owner-uid cinder-uid
# gluster volume set VOL_NAME storage.owner-gid cinder-gid

    Where:

    • VOL_NAME is the Gluster volume name.

    • cinder-uid is the UID of the cinder user.

    • cinder-gid is the GID of the cinder user.

    [Note]Note

    The default UID and GID of the cinder user is 165 on most distributions.

  3. Configure each Gluster volume to accept libgfapi connections. To do this, set each Gluster volume to allow insecure ports: 

    # gluster volume set VOL_NAME server.allow-insecure on

  4. Enable client connections from unprivileged ports. To do this, add the following line to /etc/glusterfs/glusterd.vol: 

    option rpc-auth-allow-insecure on

  5. Restart the glusterd service: 

    # service glusterd restart
 

Procedure 6.3. Configure Block Storage to use a GlusterFS back end

After you configure the GlusterFS service, complete these steps:

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

  2. Create a text file named glusterfs in /etc/cinder/.

  3. Add an entry to /etc/cinder/glusterfs for each GlusterFS share that OpenStack Block Storage should use for back end storage. Each entry should be a separate line, and should use the following format:

    HOST:/VOL_NAME

    Where:

    • HOST is the IP address or host name of the Red Hat Storage server.

    • VOL_NAME is the name an existing and accessible volume on the GlusterFS server.

    Optionally, if your environment requires additional mount options for a share, you can add them to the share's entry: 

    HOST:/VOL_NAME -o OPTIONS

    Replace OPTIONS with a comma-separated list of mount options.

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

    # chown root:cinder /etc/cinder/glusterfs

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

    # chmod 0640 FILE

  6. Configure OpenStack Block Storage to use the /etc/cinder/glusterfs file created earlier. To do so, open the /etc/cinder/cinder.conf configuration file and set the glusterfs_shares_config configuration key to /etc/cinder/glusterfs.

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

    # openstack-config --set /etc/cinder/cinder.conf \
DEFAULT glusterfs_shares_config /etc/cinder/glusterfs

    The following distributions include openstack-config:

    • CentOS

    • Fedora

    • openSUSE

    • Red Hat Enterprise Linux

    • SUSE Linux Enterprise

  7. Configure OpenStack Block Storage to use the correct volume driver, namely cinder.volume.drivers.glusterfs. To do so, open the /etc/cinder/cinder.conf configuration file and set the volume_driver configuration key to cinder.volume.drivers.glusterfs.

    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.glusterfs.GlusterfsDriver

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

    To restart the cinder volume service on CentOS, Fedora, openSUSE, RedHat Enterprise Linux, or SUSE Linux Enterprise, run:

    # service openstack-cinder-volume restart

    To restart the cinder volume service on Ubuntu or Debian, run:

    # service cinder-volume restart

OpenStack Block Storage is now configured to use a GlusterFS back end.

[Note]Note

In /etc/cinder/cinder.conf, the glusterfs_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 of this key is true, which ensures volumes are initially created as sparse files.

Setting glusterfs_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 glusterfs_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 glusterfs_sparsed_volumes false
[Important]Important

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

# setsebool -P virt_use_fusefs on

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

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