Howto: 101 Scripting ESX server installation on vSphere 4

I have been wanting to look into scripted ESX installations for a while now but haven't gotten around to it untill now. At first glance it looks a bit complicated - there a several much used deployment tools around (e.g. EDA and UDA), people are posting bunches of deployment scripts etc. I wanted to know the absolute basics - what is the simplest way to script an ESX installation?

First off, I recommend that you download the ESX and vCenter Server Installation Guide and read pp. 43-58 on scripting installations. This documentation helped me to get started more than posts on the web.
On ESX 4, there are two built-in scripts that you can run when you boot the installation CD: 'ESX scripted install to first disk' and 'ESX scripted install to first disk (overwrite VMFS)'. But that's a little boring as these scripts can't be modified.

In stead, we can let ESX server generate a script for us based on your own installation. I like this way as it simplifies things compared to the very comprehensives scripts out there - and it fits to your environment. Better to have a simple script that works than to have a do-it-all script that doesn't. You can always expand it later.

When you install ESX 4 in the default graphical mode, then a Kicstart script (ks.cfg) with your specific settings is generated and placed in the /root/ folder of your ESX installation. Make a copy of this file, as this is the one we will be using as our base script.

This script is to be copied to the root of the installation ISO. To do that, you need an ISO modifying tool like MagicISO (you need to pay 29$ to make ISO's larger than 300 MB). Open the ESX 4 installation ISO in MagicISO and copy the ks.cfg file into the root of the ISO.

Now, boot your server with the ESX ISO. When the first installation screen shows as below, then hit F2 to get 'other options'. Then shift down to the 'ESX scripted install using USB ks.cfg'. We will not be installing from USB, we will just use the command as a template and modify it to get the ks.cfg script from the CD in stead.

Modify the boot options command like this:

Boot options initrd=initrd.img vmkopts=debugLogToSerial:1 mem=512M ks=cdrom:/ks.cfg quiet

That's it. This will do a basic scripted installation of the ESX 4 server...

Mini troubleshooting: I tried to reinstall the ESX server that I had already installed, which means that there is already a VMFS partitioned disk on the server. So the clearpart command needed the --overwritevmfs flag to work. Furthermore, in the partitioning section I had to comment out some lines and in stead uncomment the 'part' commands with the --firstdisk flags.

I have pasted the basic script below for reference.

----------------sample ks.cfg----------------------

# Don't edit script in notepad or Word. Use Notepad++ or like app

accepteula

keyboard dk

auth --enablemd5 --enableshadow

#I have added the '--overwritevmfs' flag which is

#necessary when reinstalling an existing ESX

clearpart --overwritevmfs --firstdisk

install cdrom

#The encrypted password is taken from the original

#graphical install

rootpw --iscrypted $1$k364YM8i$CyveR0PWuw294uX8HLzcE0

timezone --utc 'Europe/Stockholm'

network --addvmportgroup=true --device=vmnic0 --bootproto=dhcp

part '/boot' --fstype=ext3 --size=1100 --onfirstdisk

part 'none' --fstype=vmkcore --size=110 --onfirstdisk

part 'Storage1' --fstype=vmfs3 --size=8604 --grow --onfirstdisk

virtualdisk 'esxconsole' --size=7604 --onvmfs='Storage1'

part 'swap' --fstype=swap --size=600 --onvirtualdisk='esxconsole'

part '/var/log' --fstype=ext3 --size=2000 --onvirtualdisk='esxconsole'

part '/' --fstype=ext3 --size=5000 --grow --onvirtualdisk='esxconsole'

%post --interpreter=bash

----------------sample ks.cfg EOF----------------------