RHCS从redhat4开始每个版本都差别很大，到了hedhat7，来了个翻天覆地的变化，下面是红帽官方关于这个变化的一些阐述，并附上我的简单翻译。

    Red Hat Enterprise Linux 7 High Availability Add-On introduces a new suite of technologies that underlying high-availability technology based on Pacemaker and Corosync that completely replaces the CMAN and RGManager technologies from previous releases of High Availability Add-On. Below are some of the differences between the two releases. For a more comprehensive look at the differences between releases, refer to the appendix titled "Cluster Creation with rgmanager and with Pacemaker" from the Red Hat Enterprise Linux High Availability Add-On Reference.

    7上已经使用 Pacemaker 和 Corosync 全面替代 CMAN 和 RGManager 了。

以前集群配置文件是   /etc/cluster/cluster.conf ，7改成分成两个了，一个是用于成员和投票配置:/etc/corosync/corosync.conf,一个是用于集群节点和资源配置:/var/lib/heartbeat/crm/cib.xml.

以前的 ccs 和 luci 被 pcs 和 pcsd 取代。

启动服务的service和chkconfig 被systemctl取代。

• Configuration Files — Previously, cluster configuration was found in the /etc/cluster/cluster.conf file, while cluster configuration in release 7 is in /etc/corosync/corosync.conf for membership and quorum configuration and /var/lib/heartbeat/crm/cib.xml for cluster node and resource configuration.

• Executable Files — Previously, cluster commands were in ccs by means of a command line, luci for graphical configuration. In Red Hat Enterprise Linux 7 High Availability Add-On, configuration is done by means of pcs at the command line and the pcsd Web UI configuration at the desktop.

• Starting the Service — Previously, all services including those in High Availability Add-On were performed using the service command to start services and the chkconfig command to configure services to start upon system boot. This had to be configured separately for all cluster services (rgmanager, cman, and ricci. For example:

  service rgmanager startchkconfig rgmanager on

  For Red Hat Enterprise Linux 7 High Availability Add-On, the systemctl controls both manual startup and automated boot-time startup, and all cluster services are grouped in the pcsd.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 the ricci password for the node.

  In Red Hat Enterprise Linux 7 High Availability Add-On, the pcsd Web UI requires that you authenticate as user hacluster, which is the common system user. The root user can set the password for hacluster.

• Creating Clusters, Nodes and Resources — Previously, creation of nodes were performed with the ccs by means of a command line or with luci graphical 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 exampleclusterccs -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 of pcs at the command line, or the pcsd Web 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 luci interface or deleting the cluster.conf file from each node

  In Red Hat Enterprise Linux 7 High Availability Add-On, administrators can remove a cluster by issuing the pcs cluster destroy command.