Chapter 4. Clustering

Support added for Oracle 11g in Oracle and OrLsnr Pacemaker resource agents

As of Red Hat Enterprise Linux release 6.9, the Pacemaker resource agents Oracle and OraLsnr support Oracle database 11g. (BZ#1336846)

Pacemaker now supports alert agents

You can now create Pacemaker alert agents to take some external action when a cluster event occurs. The cluster passes information about the event to the agent by means of environment variables. Agents can do anything desired with this information, such as send an email message, log to a file, or update a monitoring system. For information on configuring alert agents, see Configuring the Red Hat High Availability Add-On with Pacemaker. (BZ#1253325, BZ#1376480)

clufter is now fully supported

The clufter packages provide a tool for transforming and analyzing cluster configuration formats. They can be used to assist with migration from an older stack configuration to a newer configuration that leverages Pacemaker. The clufter tool, previously available as a Technology Preview, is now fully supported. For information on the capabilities of clufter, see the clufter(1) man page or the output of the clufter -h command. For examples of clufter usage, see the following Red Hat Knowledgebase article: https://access.redhat.com/articles/2810031. (BZ#1318326)

clufter rebased to version 0.59.8

The clufter packages have been upgraded to upstream version 0.59.8, which provides a number of bug fixes, new features, and user experience enhancements over the previous version. Among the notable updates are the following:
  • When converting either CMAN or Pacemaker stack specific configuration into the respective sequence of pcs commands with the *2pcscmd families of commands, the clufter tool no longer suggests pcs cluster cib file --config, which does not currently work for subsequent local-modification pcs commands. Instead it suggests pcs cluster cib file. (RHBZ#1328078)
  • The clufter tool outputs now may vary significantly depending on the specified distribution target since the tool now aligns the output with what the respective environment, such as the pcs version, can support. Because of this, your distribution or setup may not be supported, and you should not expect that one sequence of pcs commands that the clufter tool produces is portable to a completely different environment.
  • The clufter tool now supports several new features of the pcs tool, including alert handlers configuration. Additionally, the clufter tool supports older features recently added to the pcs tool, including resource sets for colocation and order constraints.
  • When converting either CMAN + RGManager stack specific configuration into the respective Pacemaker configuration (or sequence of pcs commands reflecting the same) with the ccs2pcs* families of commands, the clufter tool no longer refuses to convert entirely valid lvm resource agent configuration, which could happen before. (BZ#1367536)

luci interface allows administrators to verify authenticity of remote machines

An encrypted channel requires established authenticity between the endpoints to be reasonably secure and protected against man-in-the-middle attacks. Administrators using luci to manage clusters are now automatically provided with the corresponding certificate fingerprints of cluster nodes that are entered when creating a new cluster, adding nodes to a cluster, or adding an existing cluster to luci's management. This allows administrators to verify the authenticity of remote machines first before entrusting the remote nodes with credentials during standard, inverse (self-against-remote) authentication. (BZ#885028)

luci now lists explicit configured actions for individual resources

In a cluster configuration, it is useful to be able to review configured actions for given resources. This may be particularly useful when verifying that the implicit operations, such as the depth parameter of the status action, are overwritten with user configuration. More generally, being able to review configured actions can show the affect that these modifications and additions to implicit actions have on current cluster behavior.
luci now lists configured actions per individual resources in the Service Groups breakdown view, showing which parameters are disregarded for particular actions and emphasizing timeouts if they are set as enforced. Note that the view does not allow for active modifications of the actions; to modify the actions, you use the --addaction and --rmaction parameters of the ccs CLI tool. (BZ#1173942)