get-admin

I suppose easy is relative.

One of the comments to the post I made about touch free ESXi installs asked about testing without having to reboot and wait for the install process to load, and fail, to determine what went wrong. I did this testing by switching to a different console and using the Python interactive shell to load the same modules VMware uses, call their methods, and simply look at the values returned. By reading their code I was able to determine what the dialogs (the prompts presented to the admin during the install process) return, and the simply return that without the dialog occurring.

From the install screen you can switch to a different console (Alt+F1, if I recall correctly), and then access a command line (you may need to use the “unsupported” trick to get the command line).

The install process is actually quite interesting. VMware is booting, via ISOLINUX, into a full ESXi environment (instead of the standard ESXi yellow and black, they display the install dialogs), asking you which disk you want to use, then formatting that disk with VMFS and copying a virutal machine to the new VMFS volume. They then configure the boot partition to start the ESX kernel and start the ESXi management virtual machine. It’s rather interesting (well, to me) what they are able to accomplish because of the power and flexibility having such a small hypervisor affords them. Not to mention the sheer genius of using their own hypervisor to perform the install of itself…simplicity!

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Being, first and foremost, lazy and getting my paychecks for being a system administrator, I felt that the amount of work involved in loading ESXi 4.0 on my blades was entirely too much. I have well over 100 blades, each one needing to have vSphere loaded onto it, configured, and added to vCenter. Even using the directions scattered across the internet about reducing the amount of effort involved in loading vSphere was too much for me.

Others have documented how to PXE boot ESXi elsewhere on the internet, however I wasn’t interested in having a “stateless” install…I merely wanted to automate installing ESXi to the local hard drive. My blades have a single hard drive, a single generation one SSD or two SAS drives in a RAID 1 depending on the vendor, and I simply want the installer to always install to that drive without bothering me. Loading from the “remote media” functionality of the DRAC/iLO for the blades takes forever, so I wanted to be able to install using PXE and push the media over that medium.

So, having been a developer for several years I decided to dive further into the the install process than others had detailed. Turns out that eliminating all input from an administrator to load the operating system was pretty simple.

The end result is that I am able to power on a blade, hit F12 to have it PXE boot and walk away. Some time later, we can use PowerShell and the PowerCLI to find the hosts (they will be somewhere in the DHCP scope of the provisioning LAN), give them a permanent IP and hostname, then configure them and add them to vCenter. By using PXE and the interactionless (yes, I did make up that word) install, I cut the time to load ESXi from about 45 minutes (using the remote media function takes FOREVER!) to less than 10.

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