21.3. Scripts in Kickstart file

The %pre scripts are run on the system immediately after the Kickstart file has been loaded, but before it is completely parsed and installation begins. Each of these sections must start with %pre and end with %end.

The %pre script can be used for activation and configuration of networking and storage devices. It is also possible to run scripts by using interpreters available in the installation environment. Adding a %pre script can be useful if you have networking and storage that needs special configuration before proceeding with the installation, or have a script that, for example, sets up additional logging parameters or environment variables.

Debugging problems with %pre scripts can be difficult, so it is recommended only to use a %pre script when necessary.

Commands related to networking, storage, and file systems are available to use in the %pre script, in addition to most of the utilities in the installation environment /sbin and /bin directories.

You can access the network in the %pre section. However, the name service has not been configured at this point, so only IP addresses work, not URLs.

%pre --interpreter=/usr/libexec/platform-python
-- Python script omitted --
%end

The commands in the pre-install script are run after the following tasks are complete:

Each of the %pre-install sections must start with %pre-install and end with %end.

The %pre-install scripts can be used to modify the installation, and to add users and groups with guaranteed IDs before package installation.

It is recommended to use the %post scripts for any modifications required in the installation. Use the %pre-install script only if the %post script falls short for the required modifications.

The pre-install script does not run in the chroot environment.

%pre-install --interpreter=/usr/libexec/platform-python
-- Python script omitted --
%end

The %post script is a post-installation script that is run after the installation is complete, but before the system is rebooted for the first time. You can use this section to run tasks such as system subscription.

You have the option of adding commands to run on the system once the installation is complete, but before the system is rebooted for the first time. This section must start with %post and end with %end.

The %post section is useful for functions such as installing additional software or configuring an additional name server. The post-install script is run in a chroot environment, therefore, performing tasks such as copying scripts or RPM packages from the installation media do not work by default. You can change this behavior by using the --nochroot option as described below. Then the %post script will run in the installation environment, not in chroot on the installed target system.

Because the post-install script runs in a chroot environment, most systemctl commands will refuse to perform any action.

During execution of the %post section, the installation media must be still inserted.

%post --interpreter=/usr/libexec/platform-python
-- Python script omitted --
%end

# Start of the %post section with logging into /root/ks-post.log
%post --log=/root/ks-post.log

# Mount an NFS share
mkdir /mnt/temp
mount -o nolock 10.10.0.2:/usr/new-machines /mnt/temp
openvt -s -w -- /mnt/temp/runme
umount /mnt/temp

# End of the %post section
%end