I accidentally used the wrong VLAN on a portgroup in vDS while playing with NSX-T.(long story) This caused vCenter to lose access to all the hosts in a cluster.

There is a KB article that goes through a few hoops before we can get the hosts back into vCenter Server, Recovering from a management portgroup VLAN misconfiguration on a vNetwork Distributed Switch (vDS)

To resolve the issue,
As i still had access to vCenter, after configuring the right vlan in vCenter I used net-dvs to manually change the vlan on each vmkernel interface.

Note: net-dvs is not a supported command and can cause the dvswitch to go out of sync.

First, get the port number that the vmkernel interface is connected to, using the command
esxcfg-vmknic -l

From the above command, I wanted to change the vlan for vmk1.
vmk1 is connected to port 21 on the dvswitch.

To change the VLAN of the vmkernel interface, use the command.
net-dvs -v -p vDS_Name

For eg.
net-dvs -v 100 -p 21 MgmtDVS