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Cannot open Virtual Machine Console

Details

  • When you try to connect to a virtual machine console from VirtualCenter, you see one or more of these errors:

    • Error connecting: Host address lookup for server <SERVER> failed: The requested name is valid and was found in the database, but it does not have the correct associated data being resolved for Do you want to try again?

    • Error connecting: cannot connect to host <host>: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. Do you want to try again?

    • Error connecting: You need execute access in order to connect with the VMware console. Access denied for config file.

    • Unable to connect to MKS: failed to connect to server IP:903. For more information, see ESX 4.0 hosts lose network connectivity when multiple service console interfaces are configured on subnets that use DHCP IP addresses (1010828).

  • You cannot open a remote console to a virtual machine.
  • Virtual machine console is black (blank).
  • The VMware Infrastructure (VI) Client console tab session may time out or disconnect while in use.
  • Migration of virtual machines using vMotion failed.

Solution

If your network is configured such that a firewall exists between the ESX host and the client running the workstation running VI Client, you might not be able to open a virtual machine console. To connect to a virtual machine console from VI Client, port 903 needs to be open in any firewall between the the workstation running VI Client and the ESX host. This applies even if VI Client is connected to VirtualCenter and not directly to ESX host.
 
Note: Before performing the steps in this article, please refer to Restarting the Management agents on an ESX Server (1003490) for important information on restarting the Management agents.
 
To troubleshoot this issue:
  1. Log in to the VirtualCenter Server directly through Terminal Services or a Remote KVM and attempt a connection from VI Client from this system. If this method works, the firewall is likely preventing the console from working. Configure your firewall to allow communications on port 903 between the ESX host and the workstation running VI Client.

    If port 903 is not open or cannot be opened in your environment, enable the vmauthd proxy. This forces remote console communication to be sent on port 902 on the Service Console, instead of 903.

    Note: By enabling this setting there may be degradation in performance communicating to the ESX host service console, if remote consoles are heavily utilized.

    To enable the proxy:
    1. Log in to the ESX host's service console as root.
    2. Open /etc/vmware/config with a text editor. 
    3. Add the following line:

      vmauthd.server.alwaysProxy = "TRUE"

    4. Issue the following command to restart xinetd:

      service xinetd restart

  2. Verify the ESX firewall policy.  For more information, see Troubleshooting the firewall policy on an ESX Server (1003634).
  3. Verify that the ESX host and the workstation running VI Client are correctly synced to an NTP service. This is required to satisfy SSL handshaking between VI Client and ESX. For more information, see Verifying time synchronization across environment (1003736).
  4. DNS problems are a common cause of virtual machine console problems. Verify name resolution in your environment. For more information, see:
  6. After verifying DNS, open a command prompt on the VI Client machine and perform the following:

    ipconfig /flushdns
    ipconfig /registerdns

  7. Verify /var partition is not full.

  8. Verify that the permissions for the virtual machine's .vmx file are set correctly. To set the permissions, run the command:

    chmod 755 </full/path/to/virtual machine.vmx>

  9. If your ESX host has more than one service console configured, verify that they are not on the same network.
Note: If your problem still exists after trying the steps in this article, please file a support request with VMware Support and note this KB Article ID in the problem description. For more information, see How to Submit a Support Request.

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Actions
  • KB Article: 749640
  • Updated: Nov 2, 2009
  • Products:
    VMware ESX
    VMware VirtualCenter
  • Product Versions:
    VMware ESX 3.0.x
    VMware ESX 3.5.x
    VMware VirtualCenter 2.0.x
    VMware VirtualCenter 2.5.x