Scripts to run with high availability
The following sample script can be used:
- highAvailChange
- The HighAvailChange script runs whenever the high availability state changes within the Load Balancer. You can create this script to use state change information, for instance, to alert an Administrator or simply record the event.
- goActive
- The goActive script runs when the Load Balancer goes into active state and begins routing packets. This script is only invoked when high availability is defined and is not invoked when the load balancer is configured as a stand-alone. This script can be used to configure cluster addresses.
- goStandby
- The goStandby script runs when the Load Balancer goes into a standby state, monitoring the health of the active machine but not routing any packets. This script is only started when high availability is defined, and is not started when the load balancer is configured as a stand-alone. The script can be used to unconfigure cluster addresses.
- goInOp
- The goInOp script runs when the Load Balancer executor is stopped. This script can be used to unconfigure cluster addresses, or any other action that is desired when the Load Balancer stops forwarding packets.
- goIdle
- The goIdle script runs when the Load Balancer starts forwarding packets in a stand-alone environment. It should not be configured when high availability is desired.
On Linux for s/390: Load Balancer issues a gratuitous
ARP to move IP addresses from one Load Balancer to another. This mechanism is therefore tied to the
underlying network type. When running Linux for s/390, Load Balancer can natively do high
availability takeovers, complete with IP address moves, only on those interfaces which can issue a
gratuitous ARP and configure the address on the local interface. This mechanism will not work
properly on point-to-point interfaces such as IUCV and CTC and will not work properly in certain
configurations of qeth/QDIO.