31.7. Post-installation Script

You have the option of adding commands to run on the system once the installation is complete. This section must be at the end of the kickstart file and must start with the %post command. This section is useful for functions such as installing additional software and configuring an additional nameserver.

Note

If you configured the network with static IP information, including a nameserver, you can access the network and resolve IP addresses in the %post section. If you configured the network for DHCP, the /etc/resolv.conf file has not been completed when the installation executes the %post section. You can access the network, but you can not resolve IP addresses. Thus, if you are using DHCP, you must specify IP addresses in the %post section.

Note

The post-install script is run in a chroot environment; therefore, performing tasks such as copying scripts or RPMs from the installation media do not work.

--nochroot

Allows you to specify commands that you would like to run outside of the chroot environment.

The following example copies the file /etc/resolv.conf to the file system that was just installed.

%post --nochroot 
cp /etc/resolv.conf /mnt/sysimage/etc/resolv.conf

--interpreter /usr/bin/python

Allows you to specify a different scripting language, such as Python. Replace /usr/bin/python with the scripting language of your choice.

--log /path/to/logfile

Logs the output of the post-install script. Note that the path of the log file must take into account whether or not you use the --nochroot option. For example, without --nochroot:

This command is available in Red Hat Enterprise Linux 5.5 and later.

%post --log=/root/ks-post.log

with --nochroot:

%post --nochroot --log=/mnt/sysimage/root/ks-post.log

31.7.1. Examples

Register the system to a Red Hat Network Satellite, using a subshell to log the result in Red Hat Enterprise Linux 5.4 and earlier:

%post
( # Note that in this example we run the entire %post section as a subshell for logging.
wget -O- http://proxy-or-sat.example.com/pub/bootstrap_script | /bin/bash
/usr/sbin/rhnreg_ks --activationkey=<activationkey>
# End the subshell and capture any output to a post-install log file.
) 1>/root/post_install.log 2>&1

Register the system to a Red Hat Network Satellite, using the --log option to log the result in Red Hat Enterprise Linux 5.5 and later:

%post --log=/root/ks-post.log
wget -O- http://proxy-or-sat.example.com/pub/bootstrap_script | /bin/bash
/usr/sbin/rhnreg_ks --activationkey=<activationkey>

Run a script named runme from an NFS share:

mkdir /mnt/temp 
mount -o nolock 10.10.0.2:/usr/new-machines /mnt/temp open -s -w -- 
/mnt/temp/runme 
umount /mnt/temp

Note

NFS file locking is not supported while in kickstart mode, therefore -o nolock is required when mounting an NFS mount.