Managing HP Serviceguard for Linux, Tenth Edition, September 2012

If pkg1 depends on pkg2, and pkg1’s priority is lower than or equal to pkg2’s, pkg2’s
node order dominates. Assuming pkg2’s node order is node1, node2, node3, then:
• On startup:
◦ pkg2 will start on node1, or node2 if node1 is not available or does not at
present meet all of its dependencies, etc.
– pkg1 will start on whatever node pkg2 has started on (no matter where that
node appears on pkg1’s node_name list) provided all of pkg1’s other
dependencies are met there.
– If the node where pkg2 has started does not meet all pkg1’s dependencies,
pkg1 will not start.
• On failover:
If pkg2 fails on node1, pkg2 will fail over to node2 (or node3 if node2 is not
available or does not currently meet all of its dependencies, etc.)
– pkg1 will fail over to whatever node pkg2 has restarted on (no matter where
that node appears on pkg1’s node_name list) provided all of pkg1’s
dependencies are met there.
– If the node where pkg2 has restarted does not meet all pkg1’s
dependencies, pkg1 will not restart.
◦
◦ If pkg1 fails, pkg1 will not fail over.
This is because pkg1 cannot restart on any adoptive node until pkg2 is running
there, and pkg2 is still running on the original node. pkg1 cannot drag pkg2
because it has insufficient priority to do so.
• On failback:
◦ If both packages have moved from node1 to node2 and node1 becomes
available, pkg2 will fail back to node1 only if pkg2’s priority is higher than
pkg1’s:
– If the priorities are equal, neither package will fail back (unless pkg1 is not
running; in that case pkg2 can fail back).
– If pkg2’s priority is higher than pkg1’s, pkg2 will fail back to node1; pkg1
will fail back to node1 provided all of pkg1’s other dependencies are met
there;
– if pkg2 has failed back to node1 and node1 does not meet all of pkg1’s
dependencies, pkg1 will halt.
If pkg1 depends on pkg2, and pkg1’s priority is higher than pkg2’s, pkg1’s node order
dominates. Assuming pkg1’s node order is node1, node2, node3, then:
134 Planning and Documenting an HA Cluster