Hosts on a vSphere Distributed Switch Lose Connectivity to vCenter Server

Hosts on a vSphere Distributed Switch cannot connect to vCenter Server after a port group configuration.

Problem

After you change the networking configuration of a port group on a vSphere Distributed Switch that contains the VMkernel adapters for the management network, the hosts on the switch lose connectivity to vCenter Server. In the vSphere Web Client the status of the hosts is nonresponsive.

Cause

On a vSphere Distributed Switch in vCenter Server that has networking rollback disabled, the port group containing the VMkernel adapters for the management network is misconfigured in vCenter Server and the invalid configuration is propagated to the hosts on the switch.

Note: In vSphere networking rollback is enabled by default. However, you can enable or disable rollbacks at the vCenter Server level. For more information see the vSphere Networking documentation.

Solution

1. From the Direct Console User Interface (DCUI) to an affected host, use the Restore vDS option from the Network Restore Options menu to configure the uplinks and the ID of the VLAN for the management network.
   The DCUI creates a local ephemeral port and applies the VLAN and uplink configuration to the port. The DCUI changes the VMkernel adapter for the management network to use the new host local port to restore connectivity to vCenter Server.

   After the host re-connects to vCenter Server, the vSphere Web Client displays a warning that some hosts on the switch have different networking configuration from the configuration stored in vSphere distributed switch.

2. In the vSphere Web Client, configure the distributed port group for the management network with correct settings.

   Situation	Solution
   You have altered the port group configuration only once	You can roll the configuration of the port group back one step. Right-click the port group, click Restore Configuration, and select Restore to previous configuration.
   You have backed up a valid configuration of the port group	You can restore the configuration of the port group by using the backup file. Right-click the port group, click Restore Configuration, and select Restore configuration from a file. You can also restore the configuration for the entire switch, including the port group, from a backup file for the switch.
   You have performed more than one configuration step and you do not have a backup file	You must provide valid settings for the port group manually.

   For information about networking rollback, recovery, and restore, see the vSphere Networking documentation.
3. Migrate the VMkernel adapter for the management network from the host local ephemeral port to a distributed port on the switch by using the Add and Manage Hosts wizard.
   Unlike distributed ports, the ephemeral local port of the VMKernel has a non-numeric ID.

   For information about handling VMkernel adapters through the Add and Manage Hosts wizard, see the vSphere Networking documentation.

4. Apply the configuration of the distributed port group and VMkernel adapter from vCenter Server to the host.
   • Push the correct configuration of the distributed port group and VMkernel adapter from vCenter Server to the host.
     1. In the vSphere Web Client, navigate to the host.
     2. On the Configure tab, click Networking.
     3. From the Virtual switches list, select the distributed switch and click Rectify the state of the selected distributed switch on the host.
   • Wait until vCenter Server applies the settings within the next 24 hours.