Disk selection in ESXi kickstart

Automated installation is the way to deploy your ESXi configuration to your servers. After all it’s all about automating your IT operations and making your life easier. Nobody likes to do a simple task twice, so I would definitely recommend to automate your ESXi installation. ESXi uses kickstart for automating your installation. You can view more details on this in my previous post over here.

Disk selection

All kickstart scripts start with the installation of ESXi. Afterwards you can add first-boot script to configure your ESXi installation to your specific needs.

One of the first thing you need to decide is where to install your ESXi installation to. The autopart command in the kickstart file specifies where you will install your ESXi to.  You’ve got 3 options to choose from :

* Local = install ESXi onto the first local disk (local hard drive)
* Remote = install  ESXi onto the first remote disk (FC or iSCSi LUN disk)
* Driver = install ESXi to the device which uses this driver in the vmkernel to access the disk

So if your using local disk select local and if your booting from SAN use remote.

But wait! There’s a catch…

Some local disks, specifically SAS disks, are not presented to ESXi installer as local disks, but as remote disks. This is also acknowledged by VMware in this KB article.

The solution is rather simple, but you do need to know the specific driver for the controller of your local SAS disk. In my case the server was a HP BL460c G6 blade. Thanks to this (Dutch) VMUG post I was able to trace the driver (hpsa) for the SAS controller in the HP BL460c G6.

And this is where the driver option of autopart kicks in. If you have several types of servers and always want to install to the local disk, use the following command :

autopart –firstdisk=hpsa,local –overwritevmfs

In this case ESXi first tries to install to the disk access with device driver hpsa. If that fail it will try to install onto the first local disk. If both options fail, the installation of ESXi will fail and you will error will be shown onscreen.

Hope this gives you some better understanding in how ESXi installs itself onto disk. For more information have a look at the Setup Guide of ESXi here.