HP TMS zl Module Security Administrator's Guide

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Managing TMS zl Modules
Configuring High Availability Clusters
The Master module and Participant module have the same configuration
except for IP addresses. In active-standby mode, the Master handles all
network traffic, so the Participant does not have any IP addresses on the TMS
VLANs. Because of this, you cannot access the Web browser interface for the
Participant. Any configuration changes must be made to the Master and then
synchronized to the Participant. When the Master fails, the Participant takes
over as the new Master.
The Failover Process
The failover process for each HA mode is as follows:
1. The Master fails.
2. The Participant becomes the Master, and a gratuitous ARP (Address
Resolution Protocol) message is broadcast to the end nodes and routers
to update their ARP tables to associate the cluster's IP addresses with the
new Master's MAC addresses. If the original Participant (now the Master)
reboots while original Master is still offline, you will not lose your config-
uration. When the original Participant comes back online it will have the
same configuration (unless the original Master is already online, which
could occur if it had to be rebooted for some reason before the new
Master).
3. When the original Master comes back online it becomes the Participant,
regardless of the specified priority.
For example, suppose that module A is the Master (with priority 255) and
module B is the Participant (with priority 1). Module A fails, so module B
becomes the Master. Sometime later, module A comes back online. At this
point, module B remains the Master (with priority 1) and module A becomes
the Participant (with priority 255). Module B will be the Master until it fails.
Priority becomes important only when both modules come online at the same
time, such as when their host switch is rebooted.
Configuration and Boot Order for HA Members
The order in which you configure and reboot the members of an HA cluster
is extremely important. The cluster member that comes online first will be the
Master, and the module that comes online second will be the Participant,
regardless of the priority that you have specified.
HA cluster members behave according to these rules:
■ The cluster member that comes online first is the cluster Master.