Brian C. Lane <>

mkksiso is a tool for creating kickstart boot isos. In it's simplest form you can add a kickstart to a boot.iso and the kickstart will be executed when the iso is booted. If the original iso was created with EFI and Mac support the kickstart boot.iso will include this support as well.

mkksiso needs to be run as root, it depends on mounting the original iso and you need to be root to be able to do that.

mkksiso cmdline arguments

Add a kickstart and files to an iso

usage: mkksiso [-h] [-a ADD_PATHS] [-c CMDLINE] [--debug] ks input_iso output_iso

Optional arguments

-h, --help

show this help message and exit


File or directory to add to ISO (may be used multiple times)

-c CMDLINE, --cmdline CMDLINE

Arguments to add to kernel cmdline


print debugging info

-V VOLID, --volid VOLID

Set the ISO volume id, defaults to input's

Positional arguments


Kickstart to add to the ISO


ISO to modify


Full pathname of iso to be created

Create a kickstart boot.iso or DVD

Create a kickstart like you normally would, kickstart documentation can be found here, including the url and repo commands. If you are creating a DVD and only need the content on the DVD you can use the cdrom command to install without a network connection. Then run mkksiso like this:


This will create a new iso with the kickstart in the root directory, and the kernel cmdline will have inst.ks=... added to it so that it will be executed when the iso is booted (be careful not to boot on a system you don't want to wipe out! There will be no prompting).

By default the volume id of the iso is preserved. You can set a custom volid by passing -V and the string to set. The kernel cmdline will be changes, and the iso will have th custom volume id. eg.:


Adding package repos to a boot.iso

You can add repo directories to the iso using --add /PATH/TO/REPO/, make sure it contains the repodata directory by running createrepo_c on it first. In the kickstart you can refer to the directories (and files) on the iso using file:///run/install/repo/DIRECTORY/. You can then use these repos in the kickstart like this:

repo --name=extra-repo --baseurl=file:///run/install/repo/extra-repo/

Run mkksiso like so:


Create a liveimg boot.iso

You can use the kickstart liveimg command, to install a pre-generated disk image or tar to the system the iso is booting on.

Create a disk image or tar with osbuild-composer or livemedia-creator, make sure the image includes tools expected by anaconda, as well as the kernel and bootloader support. In osbuild-composer use the tar image type and make sure to include the kernel, grub2, and grub2-tools packages. If you plan to install it to a UEFI machine make sure to include grub2-efi and efibootmgr in the blueprint.

Add the root.tar.xz file to the iso using --add /PATH/TO/ROOT.TAR.XZ, and in the kickstart reference it with the liveimg command like this:

liveimg --url=file:///run/install/repo/root.tar.xz

It is also a good idea to use the --checksum argument to liveimg to be sure the file hasn't been corrupted:


When this iso is booted it will execute the kickstart and install the liveimg contents to the system without any prompting.

How it works

mkksiso first examines the system to make sure the tools it needs are installed, it will work with xorrisofs or mkisofs installed. It mounts the source iso, and copies the directories that need to be modified to a temporary directory.

It then modifies the boot configuration files to include the inst.ks command, and checks to see if the original iso supports EFI. If it does it regenerates the EFI boot images with the new configuration, and then runs the available iso creation tool to add the new files and directories to the new iso. If the architecture is x86_64 it will also make sure the iso can be booted as an iso or from a USB stick (hybridiso).

The last step is to update the iso checksums so that booting with test enabled will pass.