3.1. Simplify Administration With a Cluster Shell
In the dark past, configuring Pacemaker required the administrator to read and write XML. In true UNIX style, there were also a number of different commands that specialized in different aspects of querying and updating the cluster.
In addition, the various components of the cluster stack (corosync, pacemaker, etc.) had to be configured separately, with different configuration tools and formats.
All of that has been greatly simplified with the creation of higher-level tools, whether command-line or GUIs, that hide all the mess underneath.
Command-line cluster shells take all the individual aspects required for managing and configuring a cluster, and pack them into one simple-to-use command-line tool.
They even allow you to queue up several changes at once and commit them all at once.
Two popular command-line shells are pcs and crmsh. Clusters from Scratch is based on pcs because it comes with CentOS, but both have similar functionality. Choosing a shell or GUI is a matter of personal preference and what comes with (and perhaps is supported by) your choice of operating system.
