This article outlines steps to determine the hostname of an ESXi host from the hostId located in the log files.

• An unexpected failover in the vSphere HA (High Availability) cluster occurs.
• The vpxd logs on vCenter Server contains entries referencing hostIds similar to:
  
  Note: hostIds are host-1208 and host-1214.
  
  On the vCenter server (vpxd.log):, located by default under %ALLUSERSPROFILE%\Application Data\VMware\VMware VirtualCenter\Logs\
  
  T16:48:45.796+01:00 [01724 verbose 'DAS' opID=SWI-d75d1509] [FdmManager::GetHostList] host list version for vim.ClusterComputeResource:domain-c9 (Cluster): 21
  T16:48:45.796+01:00 [01724 verbose 'DAS' opID=SWI-d75d1509] [FdmManager::GetHostList] New host list is: (csi.HostList) {
  dynamicType = <unset>,
  faultDomainId = "44BA0E8A-D6E9-4902-86FE-A0BDE160ACF8-9-d409ae6-vCenter01",
  version = 21,

info 'Default'] [VpxdMoHost::UpdateDasState] VC state for host host-1208 (initialized -> initialized), FDM state (Live -> FDMUnreachable), src of state (host-406 -> host-406)
info 'Default'] [VpxdMoHost::UpdateDasState] VC state for host host-1214 (initialized -> initialized), FDM state (Live -> FDMUnreachable), src of state (host-406 -> host-406)

Note: The vpxd logs are located by default at:

• • Windows 2008: C:\ProgramData\VMware\VMware VirtualCenter\vpxd.cfg
  • Windows 2003: C:\Documents and Settings\All Users\Application Data\VMware\VMware VirtualCenter\vpxd.cfg
  • vCenter Server Appliance: /etc/vmware-vpx/vpxd.cfg
• The /var/log/fdm.log on ESXi hosts contains log entries referencing hostIds similar to:
  
  T14:48:45.563Z [48D03B90 info 'Cluster' opID=SWI-d75d1509] [ClusterManagerImpl::StoreDone] Wrote hostlist version 21 verbose 'Cluster' opID=SWI-2bc801f9] [ClusterSlave::LiveCheck] Heartbeat still pending for slave @ host-1208
  verbose 'Cluster' opID=SWI-2bc801f9] [ClusterSlave::LiveCheck] Heartbeat still pending for slave @ host-1214

Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment. 　

This issue occurs when the vCenter Server vpxd and ESXi host fdm logs reference hostIds rather than hostnames.

1. In the %ALLUSERSPROFILE%\Application Data\VMware\VMware VirtualCenter\Logs\vpxd log search for the Synchronizing host and the hostId.
   
   For example:
   
   T17:44:31.563Z [7FB34D20A700 info 'vpxdvpxdInvtHostCnx'] [VpxdHostSync] Synchronizing host: host-1208 of the host (server12345.domain.local, XX.XXX.XXX.XX)
   
   Where host-1208 corresponds to server 12345.

1. As user root on any host on the cluster open a Secure Shell (SSH) connection to the host.
2. Run the command:
   
   /opt/vmware/fdm/fdm/prettyPrint.sh hostlist
   
   Note: /etc/opt/vmware/fdm/hostlist is an xml file and contains information on the hostnames, IP Addresses, MAC addresses and heartbeat datastore of hosts participating in the cluster.
   This is an example of the hostlist file, where you can determine the relationship between hostId and hostName, host-1208 from the vpxd / FDM logs corresponds to ESXi hostName server12345.domain.local.
   
   Warning: The prettyPrint.sh script is only available to display information. Do not modify these files for any reason. The cluster configuration is performed exclusively by the vSphere Client or by PowerCLI.
   
   <faultDomainId>44BA0E8A-D6E9-4902-86FE-A0BDE160ACF8-9-d409ae6-vcbr04</faultDomainId>
   <version>21</version>
   <hostId>host-1208</hostId>
   <hostName>server12345.domain.local</hostName>
   <sslThumbprint>21:E5:C9:24:9F:BC:CC:AF:84:E7:6A:95:02:4C:ED:22:8A:BD:D4:93</sslThumbprint>
   <ipAddress>xx.xx.xx.xxx</ipAddress>
   <mac>xx:xx:xx:xx:xx:xa</mac>
   <mac>xx:xx:xx:xx:xx:xb</mac>
   <mac>xx:xx:xx:xx:xx:xc</mac>
   <mac>xx:xx:xx:xx:xx:xd</mac>
   <mac>xx:xx:xx:xx:xx:xe</mac>
   <mac>xx:xx:xx:xx:xx:xf</mac>
   <mac>xx:xx:xx:xx:xx:xh</mac>
   <mac>xx:xx:xx:xx:xx:xi</mac>
   <heartbeatDatastore>/vmfs/volumes/5028de7e-36c10eaa-7037-0017a4770000</heartbeatDatastore>
   <heartbeatDatastore>/vmfs/volumes/4fbf41e5-da3ba7c6-993c-0017a4770460</heartbeatDatastore>
   <hostdPort>443</hostdPort>
   <version>5.0.0</version>
   <build>474610</build>

• Collecting diagnostic information for VMware vCenter Server (1011641)
• Collecting diagnostic information for VMware ESX/ESXi using the vSphere Client (653)
• Collecting diagnostic information for VMware ESX/ESXi using the vm-support command (1010705).