6.3. In-service Software Update from Red Hat Gluster Storage

Updating Red Hat Gluster Storage 3.4 in in-service mode

1. Ensure that you have a working backup, as described in Section 6.1, “Before you update”.
2. If you have a replicated configuration, perform these steps on all nodes of a replica set.
   If you have a distributed-replicated configuration, perform these steps on one replica set at a time, for all replica sets.
   • Stop any geo-replication sessions.

     # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL stop

   • If this node is part of an NFS-Ganehsa cluster, place the node in standby mode.

     # pcs cluster standby

   • Verify that there are no pending self-heals:

     # gluster volume heal volname info

     Wait for any self-heal operations to complete before continuing.
   • If this node is part of an NFS-Ganesha cluster:
     1. Disable the PCS cluster and verify that it has stopped.

        # pcs cluster disable
        # pcs status

     2. Stop the nfs-ganesha service.

        # systemctl stop nfs-ganesha

   • If you need to update an erasure coded (dispersed) volume, set the disperse.optimistic-change-log and disperse.eager-lock options to off. Wait for at least two minutes after disabling these options before attempting to upgrade to ensure that these configuration changes take effect for I/O operations.

     # gluster volume set volname disperse.optimistic-change-log off
     # gluster volume set volname disperse.eager-lock off

   • Stop the gluster services on the storage server using the following commands:
     On Red Hat Enterprise Linux 7:

     # systemctl stop glusterd
     # pkill glusterfs
     # pkill glusterfsd

     On Red Hat Enterprise Linux 6:

     # service glusterd stop
     # pkill glusterfs
     # pkill glusterfsd

   • If you use Samba:
     1. Enable the required repository.
        On Red Hat Enterprise Linux 6.7 or later:

        # subscription-manager repos --enable=rh-gluster-3-samba-for-rhel-6-server-rpms

        On Red Hat Enterprise Linux 7:

        # subscription-manager repos --enable=rh-gluster-3-samba-for-rhel-7-server-rpms

     2. Stop the CTDB and SMB services across all nodes in the Samba cluster using the following command. Stopping the CTDB service also stops the SMB service.
        On Red Hat Enterprise Linux 7:

        # systemctl stop ctdb
        # systemctl disable ctdb

        On Red Hat Enterprise Linux 6:

        # service ctdb stop
        # chkconfig ctdb off

        This ensures different versions of Samba do not run in the same Samba cluster until all Samba nodes are updated.
     3. Verify that the CTDB and SMB services are stopped by running the following command:

        ps axf | grep -E '(ctdb|smb|winbind|nmb)[d]'

   • Update the server using the following command:

     # yum update

     Take note of the packages being updated, and wait for the update to complete.
   • If a kernel update was included as part of the update process in the previous step, reboot the server.
   • If a reboot of the server was not required, then start the gluster services on the storage server using the following command.
     On Red Hat Enterprise Linux 7:

     # systemctl start glusterd

     On Red Hat Enterprise Linux 6:

     # service glusterd start

   • Verify that you have updated to the latest version of the Red Hat Gluster Storage server.

     # gluster --version

     Compare output with the desired version in Section 1.5, “Supported Versions of Red Hat Gluster Storage”.
   • Ensure that all bricks are online. To check the status, execute the following command:

     # gluster volume status

   • Start self-heal on the volume.

     # gluster volume heal volname

   • Ensure self-heal is complete on the replica using the following command:

     # gluster volume heal volname info

   • Verify that shared storage is mounted.

     # mount | grep /run/gluster/shared_storage

3. When all nodes in the volume have been updated, run the following command to update the op-version of the cluster. This helps to prevent any compatibility issues within the cluster.

   # gluster volume set all cluster.op-version 31306

   Note

   31306 is the cluster.op-version value for Red Hat Gluster Storage 3.4 Async Update. Refer to Section 1.5, “Supported Versions of Red Hat Gluster Storage” for the correct cluster.op-version value for other versions.
4. If you use Samba:
   1. Mount /gluster/lock before starting CTDB by executing the following command:

      # mount -a

   2. If all servers that host volumes accessed via SMB have been updated, then start and re-enable the CTDB and Samba services by executing the following commands.
      On Red Hat Enterprise Linux 7:

      # systemctl start ctdb
      # systemctl enable ctdb

      On Red Hat Enterprise Linux 6:

      # service ctdb start
      # chkconfig ctdb on

   3. To verify that the CTDB and SMB services have started, execute the following command:

      ps axf | grep -E '(ctdb|smb|winbind|nmb)[d]'

5. If you had a meta volume configured prior to this upgrade, and you did not reboot as part of the upgrade process, mount the meta volume:

   # mount /var/run/gluster/shared_storage/

   If this command does not work, review the content of /etc/fstab and ensure that the entry for the shared storage is configured correctly and re-run the mount command. The line for the meta volume in the /etc/fstab file should look like the following:

   hostname:/gluster_shared_storage   /var/run/gluster/shared_storage/   glusterfs   defaults   0 0

6. If this node is part of an NFS-Ganesha cluster:
   1. If SELinux is in use, set the ganesha_use_fusefs Boolean to on.

      # setsebool -P ganesha_use_fusefs on

   2. Start the nfs-ganesha service:

      # systemctl start nfs-ganesha

   3. Enable and start the cluster.

      # pcs cluster enable
      # pcs cluster start

   4. Release the node from standby mode.

      # pcs cluster unstandby

   5. Verify that the PCS cluster is running and that the volume is exporting correctly.

      # pcs status
      # showmount -e

      NFS-ganesha enters a short grace period after performing these steps. I/O operations halt during this grace period. Wait until you see NFS Server Now NOT IN GRACE in the ganesha.log file before continuing.
7. If you use geo-replication, restart geo-replication sessions when upgrade is complete.

   # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL start

   Note

   As a result of BZ#1347625, you may need to use the force parameter to successfully restart in some circumstances.

   # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL start force

8. If you disabled the disperse.optimistic-change-log and disperse.eager-lock options in order to update an erasure-coded (dispersed) volume, re-enable these settings.

   # gluster volume set volname disperse.optimistic-change-log on
   # gluster volume set volname disperse.eager-lock on