vSwitch rescue from the CLI

Virtual Distributed Switches have many advantages over standard switches. Because you have a centralized configuration over all hosts they’re less error prone to configuration errors than standard switches. Call me old fashioned but I prefer to have at least the hosts management interface on a standard switch. In case something bad happens, you can still access the host and make changes on the interface.

Recently a customers host had failed. After restoring configuration, for some reason vmnics were swapped between vdSwitches and it wasn’t possible to configure that host neither with hostclient nor with vCenter. The customer was short on vmnics in the past and has configured Management Network on a distributed Portgroup on a distributed vSwitch. This is legal and usually not a problem. In that special case it was a problem. I was literally locked out of the host. Reassigning NICs in the DCUI didn’t work, because they were all claimed by Distributed-vSwitches thus not available for standard switches.

What now ?

There’s help, but you need to access the CLI of DCUI.
Login to DCUI console, select “Troubleshooting Options” in the main menu.

Continue reading “vSwitch rescue from the CLI”

ESXi host restore with obstacles

Unable to re-join EVC cluster after restore of ESXi system

Changing boot media of ESXi hosts (unfortunately) has become a routine job. It is based on the fact, that many flash media have a limited lifespan. To be fair, I need to point out that many customers use (cheap and dirty) USB flash sticks as boot media. But what is good in a homelab, turns out to be a bad idea in enterprise environments.

The usual procedure for media replacement is fairly simple:

  • export host configuration
  • evacuate and shut down host
  • prepare fresh boot medium with installation ISO that has the same or lower patchlevel as the old installation
  • boot freshly installed host
  • apply (intermediate) IP address if no DHCP available
  • restore host configuration
  • re-connect to cluster
  • apply patches if neccessary

So far so good. But last week I had a nasty experience with a recovered ESXi host. Continue reading “ESXi host restore with obstacles”