Support Policies for RHEL High Availability Clusters - ctdb General Policies

Updated -

Contents

Overview

Applicable Environments

  • Red Hat Enterprise Linux (RHEL) with the High Availability Add-On

Useful References and Guides

Introduction

This guide lays out Red Hat's policies applicable to the use of the Clustered Trivial Database for cifs exports - ctdb - in RHEL High Availability deployments. Users of ctdb in RHEL High Availability clusters should adhere to these policies in order to be eligible for assistance from Red Hat Support with the appropriate product support subscriptions.

Policies

Supported releases: Red Hat supports use of ctdb in all RHEL 7 and RHEL 8 releases, and in RHEL 6 Update 2 and later. That is, in RHEL 6 ctdb should be installed on a system that uses kernel, base operating system, High Availability, and (if GFS2 is used) Resilient Storage packages from RHEL 6 Update 2 or later.

Deprecation warning: As of RHEL 8.4, customers are advised to use ctdb in a RHEL High Availability or Resilient Storage cluster only under the following conditions:

  • ctdb should be managed exclusively by the ocf:heartbeat:CTDB resource agent. It should not run outside cluster control -- that is, it should not run in standalone mode or be managed by init scripts or systemd services on each node. It also should not be managed by custom cluster resources (e.g., systemd-class resources).
  • Volumes used by ctdb should contain either a GFS2 filesystem or (if High Availability is used together with Red Hat Gluster Storage) a GlusterFS filesystem.

ctdb deployments that do not meet these conditions are deprecated as of RHEL 8.4. Red Hat will cease supporting such deployments in a future major release of RHEL.

Typical samba policies and requirements apply: When using samba with ctdb to export data in an active/active manner using a RHEL Resilient Storage cluster, all other policies, limitations, and requirements for samba still apply. This may include, but is not necessarily limited to:

Policies for exporting gfs2 via CIFS with ctdb: Requirements and limitations may apply to exporting contents of a gfs2 filesystem via CIFS and ctdb.

**Samba/CTDB Rolling Update Restrictions **: When running CTDB and Samba, Red Hat strictly forbids mixing package versions from different RHEL minor releases. You may only perform rolling updates by temporarily mixing package versions that belong to the exact same RHEL minor release, such as two different package updates within RHEL 7.4. Mixing versions across different minor releases is unsupported and will cause unexpected cluster behavior. If an upgrade of the samba or ctdb needs to be updated outside the RHEL minor release then samba and ctdb should be disabled until all the cluster nodes have updated those packages.

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