Specifications

Expected Behaviors (Assuming Default Modes)
Simple Two-Node Cluster with Witness Node
Server A and Server B should already be set up with LifeKeeper core with resource hierarchies
created on Server A and extended to Server B (Server W will have no resource hierarchies extended
to it). Using the following steps, a third node will be added as the witness node.
1. Set up the witness node, making sure network communications are available to the other two
nodes.
2. Install LifeKeeper core on the witness node and properly license/activate it.
3. Install the Quorum/Witness Server Support Package on all three nodes.
4. Create comm paths between all three nodes.
5. Set desired quorum checking mode in /etc/default/LifeKeeper (majority, tcp_remote,
none/off) (select majority for this example). See Available Quorum Modes for an explanation of
these modes.
6. Set desired witness mode in /etc/default/LifeKeeper (remote_verify, none/off). See
Available Witness Modes for an explanation of these modes.
Expected Behaviors (Assuming Default Modes)
Scenario 1
Communications fail between Servers A and B
If the communications fail between Server A and Server B, the following will happen:
l Both Server A and B will begin processing communication failure events, though not
necessarily at exactly the same time.
l Both servers will perform the simple quorum check and determine that they still are in the
majority (both A and B can see W and think they have two of the three known nodes).
l Each will consult the other nodes with whom they can still communicate about the true status
of the server with whom they’ve lost communications. In this scenario, this means that Server
A will consult W about B’s status and B will also consult W about A’s status.
l Server A and B will both determine that the other is still alive by having consulted the witness
server and no failover processing will occur. Resources will be left in service where they are.
Scenario 2
Communications fail between Servers A and W
Since all nodes can and will act as witness nodes when the witness package is installed, this
scenario is the same as the previous. In this case, Server A and Witness Server W will determine
that the other is still alive by consulting with Server B.
Scenario 3
Communications fail between Server A and all other nodes (A fails)
112Configuration