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Applies to SUSE Linux Enterprise High Availability Extension 12 SP5

3 Requirements

Software Requirements
  • All machines (cluster nodes and arbitrators) that will be part of the Geo cluster have the following software installed:

    • SUSE® Linux Enterprise Server 12 SP5

    • SUSE Linux Enterprise High Availability Extension 12 SP5

    • Geo Clustering for SUSE Linux Enterprise High Availability Extension 12 SP5

Network Requirements
  • The virtual IPs to be used for each cluster site must be accessible across the Geo cluster.

  • The sites must be reachable on one UDP and TCP port per booth instance. That means any firewalls or IPsec tunnels in between must be configured accordingly.

  • Other setup decisions may require to open more ports (for example, for DRBD or database replication).

Other Requirements and Recommendations
  • All cluster nodes on all sites should synchronize to an NTP server outside the cluster. For more information, see https://documentation.suse.com/sles-12/html/SLES-all/cha-netz-xntp.html.

    If nodes are not synchronized, log files and cluster reports are very hard to analyze.

  • Use an uneven number of members in your Geo cluster. In case the network connection breaks down, this makes sure that there still is a majority of sites (to avoid a split brain scenario). In case you have an even number of cluster sites, use an arbitrator.

  • The cluster on each site has a meaningful name, for example: amsterdam and berlin.

    The cluster names for each site are defined in the respective /etc/corosync/corosync.conf files:

    totem {
        [...]
        cluster_name: amsterdam
        }

    This can either be done manually (by editing /etc/corosync/corosync.conf) or with the YaST cluster module (by switching to the Communication Channels category and defining a Cluster Name). Afterward, stop and start the pacemaker service for the changes to take effect:

    root # systemctl stop pacemaker
    root # systemctl start pacemaker
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