A cool option to install CentOS (and some other distros) is to use Kickstart. One thing I found missing in Kickstart is a possibility of adding some randomness to my installation out of the box. For example if deploying many CentOS virtual machines from one kiskstart file I wanted each of them to have a unique hostname. This is not possible to do with kickstart’s network --hostname=<my-hostname> option because it does not accept any code snippets. Instead this can be done with Kickstart’s %pre script.

Create a %pre section like so:

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%pre
echo "network --hostname=`echo centos-$RANDOM$RANDOM`" > /tmp/pre-hostname
%end

Then somewhere in the main Kickstart section place this:

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%include /tmp/pre-hostname

This command will include the network --hostname option into your main Kickstart section and you will end up with a hostname like centos-2656530171