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

The agent log indicates the Infrastructure agent is collecting data but the host is not listed under the Hosts dashboard or the Infrastructure dashboard and there is no Host object for the host under the Script console.

An Infrastructure (IC) agent has been deployed to monitor a Linux host via a locally installed Agent Manager (FglAM); when the agent starts data collection, the target host is another machine and is submitting data into that host in the data model. 

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.

Check to see if the data for the missing host is being associated with a different host by reviewing the Target Host column in the Agent Status dashboard.  If so, set the Collect System ID property to false for the missing host, and then unset the aliases property of the host that the missing data is being associated with.

Execute the following steps:

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.

   
   This property indicates to the agent whether or not to collect a unique system ID from this system. This is not always desirable when monitoring Hyper-V® systems, as some Hyper-V systems use the same ID for multiple systems and are not unique.

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 in the configuration file [FGLAM_HOME]\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.