On a location I had to update a whole bunch of SCOM UNIX/Linux Agents to SCOM 2012 R2 UR#1. However, most of them failed with many different error messages. This was a bit strange since these systems were being monitored as intended, so no errors or issues there.
For SCOM it’s crucial being able to resolve the FQDNs of the UNIX/Linux systems. Also the reverse lookup has to be okay. Otherwise the management of these systems will fail.
So per UNIX/Linux system which failed to update to the latest SCOM Agent version I ran first a ping and then used that IP address for a reverse lookup using NSLOOKUP utility. Both commands I ran from the SCOM Management Server being used to update the SCOM Agent on those UNIX/Linux systems.
When everything matched (IP address <> FQDN) I reran the upgrade of the related UNIX/Linux Agent. And guess what? 98% ran just fine, leaving a smaller number of servers not accepting this upgrade.
Whenever upgrading the SCOM 2012x Agent on a UNIX/Linux system fails, first run a ping and a reverse lookup on the SCOM Management Server being used to run those upgrades. Many times it will solve the upgrade issues, making it much easier to single out the real problematic servers.