I upgraded ESXi host from version 5.1 to version 5.5 and found out that could not vMotion any VMs from the other hosts to the upgraded one. Pretty quick investigation showed that vmk1 interface was missing on the host.
I enabled SSH for this host and very first command showed the problem:
esxcli network ip interface list
The vmk1 interface was disabled. I hoped that this
esxcli network ip interface set – -enabled=true – -interface-name=vmk1
would fix the issue, but I was wrong. Even though the interface was visible as disabled, the command could not find the interface to enable it. It seems that this command works for Standard Switch only, but in my case the interface was on Distributed Switch. The attempt to use esxcfg-vmknic ended up with the same result: I could see that vmk1 is disabled, but could not enable it.
Now, without any hope I tried to remove vmk1
esxcli network ip interface remove – -interface-name=vmk1
And it worked!
The last step was to add it back to the host. I could use esxcli network ip interface add, but was not sure how it would work. So I used vClient. I simply selected the host, then Configuration tab, Networking and a clicked on the Manage Virtual Adapters… link. Then clicked on Add, selected New virtual adapter, then VMKernel, selected the proper Port group and voila, new and enabled vmk1 interface appeared on the host.