Home / Pacemaker / Compare Redhat Cluster Releases – RHEL 7 HA vs RHEL 6 HA – Part 1

Compare Redhat Cluster Releases – RHEL 7 HA vs RHEL 6 HA – Part 1

In this article ,we will see the difference between Redhat cluster 6.x (Red Hat Enterprise Linux High Availability Add-On Release 6) and Redhat Cluster 7.x releases (Red Hat Enterprise Linux High Availability Add-On Release 7). In RHEL7 onwards “pacemaker” is the default cluster resource manager.  Corosync is open source cluster engine which is responsible to manage the cluster interconnect and maintains the same cluster configuration across all the cluster nodes. All the configuration changes will be replicated to other node using corosync cluster engine. Pacemaker and Corosync are powerful open source technologies that completely replaces the CMAN and RGManager technologies from previous Redhat cluster releases. Pacemaker has completely simplified  the the cluster configuration and administration.

Note: Pacemaker was shipping from REHL 6 onwards but not used widely since ccs /crm was part of it.

Cluster configuration file locations :

Redhat Cluster Releases Configuration files Description
Prior to Redhat Cluster 7 /etc/cluster/cluster.conf Stores all the configuration of cluster
Redhat Cluster 7 (RHEL 7) /etc/corosync/corosync.conf Membership and Quorum configuration
Redhat Cluster 7 (RHEL 7) /var/lib/heartbeat/crm/cib.xml Cluster node and Resource configuration.

 

Commands:

Configuration Method Prior to Redhat Cluster 7 Redhat Cluster 7 (RHEL 7)
Command Line utiltiy ccs pcs
GUI tool luci PCSD – Pacemaker Web GUI Utility

 

Services:

Redhat Cluster Releases Services Description
Prior to Redhat Cluster 7 rgmanager Cluster Resource Manager
Prior to Redhat Cluster 7 cman Manages cluster quorum and cluster membership.
Prior to Redhat Cluster 7 ricci To provide access to luci web-Interface.
Redhat Cluster 7 (RHEL 7) pcsd.service Cluster  Resource Manager
Redhat Cluster 7 (RHEL 7) corosync.service Manages cluster quorum and cluster membership.

 

Cluster user:

User Access Prior to Redhat Cluster 7 Redhat Cluster 7 (RHEL 7)
Cluster user name ricci hacluster

 

How simple to create a cluster on RHEL 7 ?

Redhat Cluster Releases Cluster Creation Description
Prior to Redhat Cluster 7 ccs -h node1.ua.com –createcluster uacluster Create  cluster on first node  using ccs
Prior to Redhat Cluster 7 ccs -h node1.ua.com –addnode node2.ua.com Add the second node  to the existing cluster
Redhat Cluster 7 (RHEL 7) pcs cluster setup uacluster node1 node2 Create a cluster on both the nodes using pcs

 

Is there any pain to remove a cluster in RHEL 7 ?  No. It’s very simple.

Redhat Cluster Releases Remove  Cluster Description
Prior to Redhat Cluster 7 rm /etc/cluster/cluster.conf Remove the cluster.conf file on each cluster nodes
Prior to Redhat Cluster 7 service rgmanager stop; service cman stop; service ricci stop; Stop the cluster services on each cluster nodes
Prior to Redhat Cluster 7 chkconfig rgmanager off; chkconfig cman  off; chkconfig ricci off; Disable the cluster services from startup
Redhat Cluster 7 (RHEL 7) pcs cluster destroy Destroy the cluster in one-shot using pacemaker

 

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One comment

  1. This is a great article thanks. On my RHEL7.2 system my cib file is in a different place.

    find / -name cib.xml -ls
    34460130 8 -rw——- 1 hacluster haclient 5766 Jul 7 10:34 /var/lib/pacemaker/cib/cib.xml

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