Chapter 6. Upgrading Red Hat Gluster Storage to Red Hat Enterprise Linux 7

Important

RHEL 8 is supported only for new installations of Red Hat Gluster Storage 3.5.2. Upgrades to RHEL 8 based Red Hat Gluster Storage 3.5.2 are not supported. Red Hat Gluster Storage is not supported on Red Hat Enterprise Linux 6 (RHEL 6) from 3.5 Batch Update 1 onwards, refer to Table 1.3, “Version Details”
Prerequisites to upgrade from Red Hat Enterprise Linux 6 based Red Hat Gluster Storage to Red Hat Enterprise Linux 7 based Red Hat Gluster Storage are as follow:
  • RHEL6 channel subscriptions are required.
  • Upgrade servers before upgrading clients.
Upgrading from Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7 is an offline procedure that results in Gluster node downtime, because volumes are offline during the upgrade process.

6.1. Preparing System for Upgrade

Important

If the system is already registered through Red Hat Subscription Manager, skip the registration steps and start the backup of the Gluster configuration files.
  1. Migrate from Red Hat Network Classic to Red Hat Subscription Manager

    Verify that your system is not on the legacy Red Hat Network Classic update system:
    # migrate-rhs-classic-to-rhsm --status
    If the system is on Red Hat Network Classic, migrate to Red Hat Subscription Manager using: Migrating from RHN to RHSM in Red Hat Enterprise Linux.
  2. Register the system with Red Hat Subscription Manager

    To register the system with Red Hat Network, execute the following command. Enter your Red Hat Network username and password that have the Red Hat Enterprise Linux entitlements:
    # subscription-manager register --username=user_name --password=password
  3. Identify the available entitlement pools

    Find the entitlement pools containing the Red Hat Enterprise Linux 6 repositories:
    # subscription-manager list --available
  4. Attach the entitlement pool to the system

    Use the pool identifier to attach the Red Hat Enterprise Linux 6 entitlements.
    # subscription-manager attach --pool=pool_ID
  5. Enable the repositories

    Enable the Red Hat Enterprise Linux 6, scalable file system, and Red Hat Gluster Storage repositories:
    # subscription-manager repos --enable=rhel-6-server-rpms --enable=rhel-scalefs-for-rhel-6-server-rpms --enable=rhs-3-for-rhel-6-server-rpms
  6. Back up the Gluster configuration files

    Note

    It is recommended to make a complete backup before you update your system. Refer to https://access.redhat.com/solutions/1484053 to know one possible approach.
    1. Ensure that the following configuration directories and files are backed up:
      • /var/lib/glusterd
      • /etc/glusterfs
    2. For systems with samba-ctdb enabled cluster, create a new directory to store the backup:
      # mkdir backup_folder_name
      # cd backup_folder_name
    3. Execute the following command to take a backup of samba-ctdb data:
      for each in `ctdb getdbmap | grep PERSISTENT | cut -d" " -f2 | cut -d":" -f2`; do echo $each ; ctdb backup_folder_name $each ${each}.bak; done
  7. Stop all Gluster services, volumes, and processes

    1. Stop any geo-replication sessions:
      # gluster volume geo-replication MASTER_VOL SLAVE_HOST::SLAVE_VOL stop
    2. Stop all volumes:
      # for vol in `gluster volume list`; do gluster --mode=script volume stop $vol; sleep 2s; done
    3. Stop the Gluster processes:
      # service glusterd stop
      # pkill glusterfs
      # pkill glusterfsd
    4. For systems with a samba-ctdb enabled cluster, stop the CTDB services:
      # service ctdb stop
  8. Update the system

    Update the system to the latest minor version of Red Hat Enterprise Linux 6:
    # yum update
  9. Reboot

    Reboot the system:
    # reboot
  10. Verify the version number

    Check the current version number of the updated Red Hat Enterprise Linux 6 system:
    # cat /etc/redhat-release
    Ensure the version number is 6.10.