Kickstart script file format reference

Use the %packages command to begin a Kickstart section which describes the software packages to be installed. The %packages section must end with the %end command.

You can specify packages by environment, group, module stream, module profile, or by their package names. Several environments and groups that contain related packages are defined. See the repository/repodata/*-comps-repository.architecture.xml file on the CentOS 8 Installation DVD for a list of environments and groups.

The *-comps-repository.architecture.xml file contains a structure describing available environments (marked by the <environment> tag) and groups (the <group> tag). Each entry has an ID, user visibility value, name, description, and package list. If the group is selected for installation, the packages marked mandatory in the package list are always installed, the packages marked default are installed if they are not specifically excluded elsewhere, and the packages marked optional must be specifically included elsewhere even when the group is selected.

You can specify a package group or environment using either its ID (the <id> tag) or name (the <name> tag).

If you are not sure what package should be installed, CentOS Project recommends you to select the Minimal Install environment. Minimal Install provides only the packages which are essential for running CentOS 8. This will substantially reduce the chance of the system being affected by a vulnerability. If necessary, additional packages can be added later after the installation. For more details on Minimal Install, see the Installing the Minimum Amount of Packages Required section of the Security Hardening in RHEL 8 document. Note that Initial Setup can not run after a system is installed from a Kickstart file unless a desktop environment and the X Window System were included in the installation and graphical login was enabled.

These commands can be used within the %packages section of a Kickstart file.

You can change the default behavior of the %packages section by using several options. Some options work for the entire package selection, others are used with only specific groups.

The following options are available for the %packages sections. To use an option, append it to the start of the package selection section. For example:

The options in this list only apply to a single package group. Instead of using them at the %packages command in the Kickstart file, append them to the group name. For example:

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, 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.

The %pre scripts ignore missing files for the %include commands. This is useful for generating the included files in the %pre section, and having them loaded later.

The following options can be used to change the behavior of pre-installation scripts. To use an option, append it to the %pre line at the beginning of the script. For example:

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 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 post-install script runs in a chroot environment, most systemctl commands will refuse to perform any action. For more information, see the Behavior of systemctl in a chroot Environment section of the Configuring and managing system administration in RHEL 8 document.

Note that during execution of the %post section, the installation media must be still inserted.

The following options can be used to change the behavior of post-installation scripts. To use an option, append it to the %post line at the beginning of the script. For example:

This example of a %post section mounts an NFS share and executes a script named runme located at /usr/new-machines/ on the share. Note that NFS file locking is not supported while in Kickstart mode, therefore the -o nolock option is required.