No data displayed and no Host object created for host monitored by Infrastructure agent that appears to be collecting data. (4261921)

This problem can occur when the system ID reported for two or more hosts is the same. When the system IDs are the same, the data associated with one host can be associated with the first host that was monitored that has the same system ID. This is known as Host Aliasing.

This is issue is very common in Linux VMs (monitored by UnixAgentPlus agents) that have been cloned from a Template because it requires an extra step to change the System ID from that of the Template.

1. Run the following script to find out if there is a Host object that references the missing host in its "aliases" property.
   ____________
   def msg = [];
   def objs = #!Host: aliases != $null#.topologyObjects?.each {
   msg << "Aliases for Host:" + it.name;
   
   msg += it.aliases;
   }
   msg +="----";
   return msg.join('\n');
   ____________
2. If the missing host is referenced from the aliases property of a different Host object note the name of the host that contains the aliases and continue with the remaining steps.
3. Set the "Collect System ID" property to false under the properties of the Infrastructure agent monitoring the missing host, and then deactivate and activate the agent.
4. If a host is monitored locally (from an FglAM on the monitored host) disable the collection of the ID under the FglAM also. 
   Set "system.id.enabled" to "false" under the client.confg file (%fglamhome%\state\default\config\client.config) and restart the FglAM.
   
   system.id.enabled = false;
5. Unset the aliases property of the Host object noted in step 2.
   
   Edit the following script so that it contains the name of the host that contained the aliases (the host noted in step 2), and then run the script.
   ____________
   def topSvc = server.TopologyService;
   #!Host : name = 'hostname_from_step2'#.topologyObjects?.each{
   def tmp = topSvc.beginUpdate(it);
   tmp.unset("aliases");
   topSvc.endUpdate(tmp);
   }
   return true;
   ____________
6. Wait 5 minutes and check to see if the Host object is created for the missing host.

To prevent this issue from affecting new UnixAgentPlus agents in the future, change the default value for new agents.