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Chapter 8. Clustering and High Availability

Administrative UI enhancements

Luci, the web-based administrative UI for configuring clusters, has been updated to include the following:

  • A confirmation dialog box appears when removing a clustered service.
  • The UI includes an improved restart icon.
  • The Add a child resource button has been simplified.
  • An option to enable debugging from the UI has been added.
Automatic timeout of inactive luci authenticated sessions

As of Red Hat Enterprise Linux 6.3, luci authenticated sessions automatically time out after 15 minutes of inactivity. This period can be configured in the /etc/sysconfig/luci file by modifying the who.auth_tkt_timeout parameter.

New libqb package

The libqb package provides a library with the primary purpose of providing high performance client server reusable features, such as high performance logging, tracing, inter-process communication, and polling. This package is introduced as a dependency of the pacemaker package, and is considered a Technology Preview in Red Hat Enterprise Linux 6.3.

Pacemaker now uses libqb logging

Because of the newly added libqb dependency, pacemaker now uses its logging functionality to provide less verbosity while keeping the ability to debug and support pacemaker.

Utilizing CPG API for inter-node locking

Rgmanager includes a feature which enables it to utilize Corosync's Closed Process Group (CPG) API for inter-node locking. This feature is automatically enabled when Corosync's Redundant Ring Protocol (RRP) feature is enabled. Corosync's RRP feature is considered fully supported. However, when used with the rest of the High-Availability Add-Ons, it is considered a Technology Preview.