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Appendix A. Upgrading From Red Hat Enterprise Linux 6 High Availability Add-On
This appendix provides an overview of upgrading Red Hat Enterprise Linux High Availability Add-On from release 6 to release 7.
A.1. Overview of Differences Between Releases
The Red Hat Enterprise Linux 7 High Availability Add-On introduces a new suite of technologies that underlie high-availability systems. These technologies are based on Pacemaker and Corosync and they replace the CMAN and RGManager technologies from previous releases of the High Availability Add-On. Below are some of the differences between the two releases. For a more comprehensive look at the differences between releases, see the appendix titled "Cluster Creation with rgmanager and with Pacemaker" from the Red Hat Enterprise Linux High Availability Add-On Reference.
- Configuration Files — Previously, cluster configuration was found in the
/etc/cluster/cluster.conffile, while cluster configuration in release 7 is in/etc/corosync/corosync.conffor membership and quorum configuration and/var/lib/pacemaker/cib/cib.xmlfor cluster node and resource configuration. - Executable Files — Previously, cluster commands were in
ccsby means of a command line,lucifor graphical configuration. In Red Hat Enterprise Linux 7 High Availability Add-On, configuration is done by means ofpcsat the command line and thepcsdWeb UI configuration at the desktop. - Starting the Service — Previously, all services including those in High Availability Add-On were performed using the
servicecommand to start services and thechkconfigcommand to configure services to start upon system boot. This had to be configured separately for all cluster services (rgmanager,cman, andricci. For example:service rgmanager start chkconfig rgmanager on
For Red Hat Enterprise Linux 7 High Availability Add-On, thesystemctlcontrols both manual startup and automated boot-time startup, and all cluster services are grouped in thepcsd.service. For example:systemctl start pcsd.service systemctl enable pcsd.service pcs cluster start -all
- User Access — Previously, the root user or a user with proper permissions can access the
luciconfiguration interface. All access requires thericcipassword for the node.In Red Hat Enterprise Linux 7 High Availability Add-On, thepcsdWeb UI requires that you authenticate as userhacluster, which is the common system user. Therootuser can set the password forhacluster. - Creating Clusters, Nodes and Resources — Previously, creation of nodes were performed with the
ccsby means of a command line or withlucigraphical interface. Creation of a cluster and adding nodes is a separate process. For example, to create a cluster and add a node by means of the command line, perform the following:ccs -h node1.example.com --createcluster examplecluster ccs -h node1.example.com --addnode node2.example.com
In Red Hat Enterprise Linux 7 High Availability Add-On, adding of clusters, nodes, and resources are done by means ofpcsat the command line, or thepcsdWeb UI. For example, to create a cluster by means of the command line, perform the following:pcs cluster setup examplecluster node1 node2 ...
- Cluster removal — Previously, administrators removed a cluster by deleting nodes manually from the
luciinterface or deleting thecluster.conffile from each nodeIn Red Hat Enterprise Linux 7 High Availability Add-On, administrators can remove a cluster by issuing thepcs cluster destroycommand.
