As of the Red Hat Enterprise Linux 6.1 release and later, the Red Hat High Availability Add-On provides support for SNMP traps. For information on configuring SNMP traps with the Red Hat High Availability Add-On, refer to Chapter 10, SNMP Configuration with the Red Hat High Availability Add-On.

As of the Red Hat Enterprise Linux 6.1 release and later, the Red Hat High Availability Add-On provides support for the ccs cluster configuration command. For information on the ccs command, refer to Chapter 5, Configuring Red Hat High Availability Add-On With the ccs Command and Chapter 6, Managing Red Hat High Availability Add-On With ccs.

The documentation for configuring and managing Red Hat High Availability Add-On software using Conga has been updated to reflect updated Conga screens and feature support.

For the Red Hat Enterprise Linux 6.1 release and later, using ricci requires a password the first time you propagate updated cluster configuration from any particular node. For information on ricci refer to Section 2.14, “Considerations for ricci”.

You can now specify a Restart-Disable failure policy for a service, indicating that the system should attempt to restart the service in place if it fails, but if restarting the service fails the service will be disabled instead of being moved to another host in the cluster. This feature is documented in Section 3.10, “Adding a Cluster Service to the Cluster” and Appendix B, HA Resource Parameters.

You can now configure an independent subtree as non-critical, indicating that if the resource fails then only that resource is disabled. For information on this feature see Section 3.10, “Adding a Cluster Service to the Cluster” and Section C.4, “Failure Recovery and Independent Subtrees”.

This document now includes the new chapter Chapter 9, Diagnosing and Correcting Problems in a Cluster.

Red Hat Enterprise Linux now provides support for running Clustered Samba in an active/active configuration. For information on clustered Samba configuration, refer to Chapter 11, Clustered Samba Configuration.

Although any user able to authenticate on the system that is hosting luci can log in to luci, as of Red Hat Enterprise Linux 6.2 only the root user on the system that is running luci can access any of the luci components until an administrator (the root user or a user with administrator permission) sets permissions for that user. For information on setting luci permissions for users, refer to Section 3.3, “Controlling Access to luci”.

Red Hat High-Availability Add-On nodes can communicate with each other using the UDP unicast transport mechanism. For information on configuring UDP unicast, refer to Section 2.13, “UDP Unicast Traffic”.

You can now configure some aspects of luci's behavior by means of the /etc/sysconfig/luci file. For example, you can specifically configure the only IP address luci is being served at. For information on configuring the only IP address luci is being served at, refer to Table 2.2, “Enabled IP Port on a Computer That Runs luci”. For information on the /etc/sysconfig/luci file in general, refer to Section 2.4, “Configuring luci with /etc/sysconfig/luci”.

The ccs command now includes the --lsfenceopts option, which prints a list of available fence devices, and the --lsfenceopts fence_type option, which prints each available fence type. For information on these options, refer to Section 5.6, “Listing Fence Devices and Fence Device Options”.

The ccs command now includes the --lsserviceopts option, which prints a list of cluster services currently available for your cluster, and the --lsserviceopts service_type option, which prints a list of the options you can specify for a particular service type. For information on these options, refer to Section 5.11, “Listing Available Cluster Services”.

The Red Hat Enterprise Linux 6.2 release provides support for the VMware (SOAP Interface) fence agent. For information on fence device parameters, refer to Appendix A, Fence Device Parameters.

The Red Hat Enterprise Linux 6.2 release provides support for the RHEV-M REST API fence agent, against RHEV 3.0 and later. For information on fence device parameters, refer to Appendix A, Fence Device Parameters.

As of the Red Hat Enterprise Linux 6.2 release, when you configure a virtual machine in a cluster with the ccs command you can use the --addvm option (rather than the addservice option). This ensures that the vm resource is defined directly under the rm configuration node in the cluster configuration file. For information on configuring virtual machine resources with the ccs command, refer to Section 5.12, “Virtual Machine Resources”.

This document includes a new appendix, Appendix D, Cluster Service Resource Check and Failover Timeout. This appendix describes how rgmanager monitors the status of cluster resources, and how to modify the status check interval. The appendix also describes the __enforce_timeouts service parameter, which indicates that a timeout for an operation should cause a service to fail.

This document includes a new section, Section 2.12, “Configuring the iptables Firewall to Allow Cluster Components”. This section shows the filtering you can use to allow multicast traffic through the iptables firewall for the various cluster components.