Before upgrading an ESXi host, it is best practice to to look at VMware HCL and check compatibility of host and IO devices. The combination of driver version, firmware version and ESXi release is crucial for compatibility. Even minor updates might lead to loss of HCL compatibility. A system that used to be HCL compliant at time of deployment, might no longer be compatible after e.g. the third ESXi update release. Updates can bring new driver versions which in turn might require higher firmware versions.
If you’re lucky you may have a software solution that keeps track of all your firmware and driver versions. Runecast Analyzer for example does a pretty good job and shows you current compatibility issues with a single click. Furthermore you can simulate updates/upgrades to any higher vSphere version and the resulting HCL status.
Unfortunately many customers do not have a software solution like that. In these cases you need to go back to the roots (literally) and gather all information on the ESXi shell. To do so you need to enable SSH service on all hosts you want to verify. That can be done in the vSphere-Client or more elegant and faster by a PowerCLI command.
Continue reading “Read HBA Driver and Firmware Version”
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.
Continue reading “vSwitch rescue from the CLI”
Login to DCUI console, select “Troubleshooting Options” in the main menu.
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”