Cold migration or deploying template fails with the error: Cannot connect to host

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• In vCenter Server, cold migration and deploying a template fail
• You see the error:
  
  Cannot connect to host
  
  
• The vpxa.log contains entries similar to:
  
  [2011-01-12 15:08:47.389 F7E716C0 info 'Libs' opID=1CC1CD4C-00001B45-36] Cannot connect to server 10.16.24.68:902: Connection refused
  [2011-01-12 15:08:47.389 F7E716C0 info 'Libs' opID=1CC1CD4C-00001B45-36] CnxAuthdConnect: Returning false because CnxAuthdConnectTCP failed
  [2011-01-12 15:08:47.389 F7E716C0 info 'Libs' opID=1CC1CD4C-00001B45-36] CnxConnectAuthd: Returning false because CnxAuthdConnect failed
  [2011-01-12 15:08:47.389 F7E716C0 info 'Libs' opID=1CC1CD4C-00001B45-36] Cnx_Connect: Returning false because CnxConnectAuthd failed
  [2011-01-12 15:08:47.389 F7E716C0 info 'Libs' opID=1CC1CD4C-00001B45-36] Cnx_Connect: Error message: Failed to connect to server 10.10.10.1:902
  [2011-01-12 15:08:47.389 F7E716C0 warning 'Libs' opID=1CC1CD4C-00001B45-36] [NFC ERROR] NfcNewAuthdConnectionEx: Failed to connect to peer (numRetries=2). Error: Failed to connect to server 10.16.24.68:902
  [2011-01-12 15:08:47.389 F7E716C0 warning 'Libs' opID=1CC1CD4C-00001B45-36] [NFC ERROR] NfcNewAuthdConnectionEx: Failed to connect to peer. Error: Failed to connect to server 10.10.10.1:902
  [2011-01-12 15:08:47.389 F7E716C0 error 'App' opID=1CC1CD4C-00001B45-36] [VpxNfcClient] Unable to connect to NFC server: Failed to connect to server 10.10.10.1:902
  
  
• vMotion is successful
• The ESX host does not disconnect from vCenter Server

template-deployment deploy-template-fails virtual-machine-template

Environment

VMware ESX 4.1.x
VMware ESX 4.0.x
VMware vCenter Server 4.1.x
VMware vCenter Server 4.0.x

Resolution

This issue is now resolved in VMware ESX 4.1 Update 2. For further details please see the Resolved Issues section in the VMware ESX 4.1 Update 2 Release Notes.

For information relating to this issue on earlier versions of ESX 4.1, please see the below information:

Note: If virtual machines are disconnecting then reconnecting, see vCenter Server displays the error: Failed to connect to host (1010837) for a resolution.

The host is connected to vCenter Server, which means that port 902 UDP is being sent from the ESX host to the vCenter Server. The NFC errors indicate that there is a network issue between the host and destination server.

To test the network:

1. Run the command:
   
   # ssh -p 902 <ESXhost>
   
   Verify that port 902 TCP is open on the source and destination ESX host. If the port is blocked, you see the error:
   
   [root@bs-bcs-h131 root]# ssh -p 902 10.21.49.132
   ssh: connect to host 10.21.49.132 port 902: Connection refused
   
   If the connection is refused, ensure that port 902 TCP is not blocked in your physical network.
   
   
2. Check the firewall settings of both the source and destination ESX hosts for port 902 with the command:
   
   # esxcfg-firewall -q
   
   You should see these rules:
   
   Chain INPUT
   2 104 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:902 state NEW
   
   Chain OUTPUT
   0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:902 state NEW
   0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:902 state NEW
   218K 43M ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 udp dpt:902 state NEW
   

Additional Information

VMware vCenter Server displays the error: Failed to connect to host
Working with firewall rules in ESX 4.x