Scheduler not picking up new IP for machine

Products

• Autosys Workload Automation

Issue/Introduction

A machine is defined with the node name pointing to a DNS alias that can switch between machineA and machineB. Normally the alias points to the IP for machineA which has an active agent. On occasion, an agent is brought up on machineB and the alias is switched to resolve to the IP for machineB. When this occurs, jobs that run on the machine are still sent to machineA.

Resolution

Check the $AUTOUSER/config.$AUTOSERV file on the Scheduler machine and look for this parameter...

EnableIPCaching=1

If that is set to 1, the Scheduler is caching the IP's for machines. If the Scheduler has cached an IP for a machine, it will continue to use that IP in cache until one of the following occurs...

1. It fails to connect to the agent on the machine using the cached IP
2. The Scheduler is restarted

If the IP for the DNS alias changes machineB but the agent on machineA is still active, the Scheduler is still able to make successful connections to the agent on machineA. Therefore, it will continue to use the cached IP. 

To trigger the Scheduler to perform a new IP lookup for the DNS alias, either shut down the agent on machineA or stop/restart the Scheduler.