Getting Started

  1. On Fedora CoreOS or RHEL CoreOS
  2. Run from a container
  3. Via a Fedora RPM
  4. Install with Cargo
  5. Build and install from source tree
  6. Run from a live image using kernel command-line options
    1. Kernel command line options for coreos-installer running as a service
    2. Installing from ISO
    3. Installing from PXE

On Fedora CoreOS or RHEL CoreOS

coreos-installer is included in Fedora CoreOS and RHEL CoreOS. Just run coreos-installer from the command line. Fedora CoreOS provides live CD and network boot images you can run from RAM; you can use these to run coreos-installer to install Fedora CoreOS or RHEL CoreOS to disk.

Run from a container

You can run coreos-installer from a container. You’ll need to bind-mount /dev and /run/udev, as well as a data directory if you want to access files in the host. For example:

sudo podman run --pull=always --privileged --rm \
    -v /dev:/dev -v /run/udev:/run/udev -v .:/data -w /data \
    quay.io/coreos/coreos-installer:release \
    install /dev/vdb -i config.ign

Via a Fedora RPM

coreos-installer is packaged in Fedora:

sudo dnf install coreos-installer

Note in fact you can also do this inside a podman run --privileged type container configured similarly to the above for the “pre-built container” path, not necessarily the host’s root filesystem. See also toolbox.

Install with Cargo

You can also install just the coreos-installer binary with Rust’s Cargo package manager:

cargo install coreos-installer

Build and install from source tree

To build from the source tree:

make

To install the binary and systemd units to a target rootfs (e.g. under a coreos-assembler workdir):

make install DESTDIR=/my/dest/dir

Run from a live image using kernel command-line options

If you want a fully automated install, you can configure the Fedora CoreOS live CD or netboot image to run coreos-installer and then reboot the system. You do this by passing coreos.inst.<arg> arguments on the kernel command line.

Kernel command line options for coreos-installer running as a service

  • coreos.inst.install_dev - The block device on the system to install to, such as /dev/sda. Mandatory.
  • coreos.inst.stream - Download and install the current release of Fedora CoreOS from the specified stream. Optional; defaults to installing from local media if run from CoreOS live ISO or PXE media, and to stable on other systems.
  • coreos.inst.image_url - Download and install the specified CoreOS image, overriding coreos.inst.stream. Optional.
  • coreos.inst.ignition_url - The URL of the Ignition config. Optional. If missing, no Ignition config will be embedded, which is probably not what you want.
  • coreos.inst.platform_id - The Ignition platform ID of the platform the CoreOS image is being installed on. Optional; defaults to metal. Normally this should be specified only if installing inside a virtual machine.
  • coreos.inst.save_partlabel - Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions need not exist. Optional.
  • coreos.inst.save_partindex - Comma-separated indexes of partitions to preserve during the install. Ranges (m-n) are permitted, and either m or n can be omitted. The specified partitions need not exist. Optional.
  • coreos.inst.insecure - Permit the OS image to be unsigned. Optional.
  • coreos.inst.skip_reboot - Don’t reboot after installing. Optional.

Installing from ISO

Download a Fedora CoreOS ISO image:

podman run --security-opt label=disable --pull=always --rm -v .:/data -w /data \
    quay.io/coreos/coreos-installer:release download -f iso

The ISO image can install in either legacy boot (BIOS) mode or in UEFI mode. You can boot it in either mode, regardless of what mode the OS will boot from once installed.

Burn the ISO to disk and boot it, or use ISO redirection via a LOM interface. Alternatively you can use a VM like so:

virt-install --name cdrom --ram 4500 --vcpus 2 --disk size=20 --accelerate \
    --cdrom /path/to/fedora-coreos-32.20200809.2.1-live.x86_64.iso --network default

Alternatively you can use qemu directly. Create a disk image to use as install target:

qemu-img create -f qcow2 fcos.qcow2 8G

Now, run the following qemu command:

qemu-system-x86_64 -accel kvm -name fcos -m 4500 -cpu host -smp 2 \
    -netdev user,id=eth0,hostname=coreos -device virtio-net-pci,netdev=eth0 \
    -drive file=/path/to/fcos.qcow2,format=qcow2 \
    -cdrom /path/to/fedora-coreos-32.20200809.2.1-live.x86_64.iso

Once you have reached the boot menu, press <TAB> (isolinux) or e (grub) to edit the kernel command line. Add the parameters to the kernel command line telling it what you want it to do. For example:

  • coreos.inst.install_dev=/dev/sda
  • coreos.inst.ignition_url=http://example.com/config.ign

Now press <ENTER> (isolinux) or <CTRL-x> (grub) to kick off the install.

The install will complete and eventually reboot the machine. After reboot the machine will boot into the installed system and the embedded Ignition config will run on first boot.

Installing from PXE

Download a Fedora CoreOS PXE kernel, initramfs, and rootfs image:

podman run --security-opt label=disable --pull=always --rm -v .:/data -w /data \
    quay.io/coreos/coreos-installer:release download -f pxe

The PXE image can install in either legacy boot (BIOS) mode or in UEFI mode. You can boot it in either mode, regardless of what mode the OS will boot from once installed.

Here is an example pxelinux.cfg for booting the installer images with PXELINUX:

DEFAULT pxeboot
TIMEOUT 20
PROMPT 0
LABEL pxeboot
    KERNEL fedora-coreos-32.20200809.2.1-live-kernel-x86_64
    APPEND initrd=fedora-coreos-32.20200809.2.1-live-initramfs.x86_64.img,fedora-coreos-32.20200809.2.1-live-rootfs.x86_64.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://192.168.1.101:8000/config.ign
IPAPPEND 2

If you don’t know how to use this information to test a PXE install you can start with something like these instructions for testing out PXE installs via a local VM + libvirt.