# Configure the baremetal nodes to pxeboot with UEFI into RHCOS
A high level overview of how a baremetal node in the Fedora Infra gets booted via UEFI is as follows.

- Server powered on
- Gets ip via dhcp
- DHCP server uses `next-server` command to point the Server to next contact the tftpboot server and retrieve `grub.cfg`
- tftpboot serves `grub.cfg`
- Sysadmin manually chooses the correct UEFI menu to boot
- tftpboot serves kernal and initramfs to the server
- Server boots with kernal and initramfs, and retrieves ingition file from `os-control01`

=== Resources

- [1] https://pagure.io/fedora-infra/ansible/blob/main/f/roles/dhcp_server[Ansible Role DHCP Server]
- [2] https://pagure.io/fedora-infra/ansible/blob/main/f/roles/tftp_server[Ansible Role tftpboot server]

=== UEFI Configuration
The configuration for UEFI booting is contained in the `grub.cfg` config which is not currently under source control. It is located on the `batcave01` at: `/srv/web/infra/bigfiles/tftpboot2/uefi/grub.cfg`.

The following is a sample configuration to install a baremetal OCP4 worker in the Staging cluster.

----
menuentry 'RHCOS 4.8 worker staging' {
linuxefi images/RHCOS/4.8/x86_64/rhcos-4.8.2-x86_64-live-kernel-x86_64 ip=dhcp nameserver=10.3.163.33 coreos.inst.install_dev=/dev/sda coreos.live.rootfs_url=http://10.3.166.50/rhcos/rhcos-4.8.2-x86_64-live-rootfs.x86_64.img coreos.inst.ignition_url=http://10.3.166.50/rhcos/worker.ign
initrdefi images/RHCOS/4.8/x86_64/rhcos-4.8.2-x86_64-live-initramfs.x86_64.img
}
----

Any new changes must be made here. Writing to this file requires one to be a member of the `sysadmin-main` group, so best to instead create a ticket in the Fedora Infra issue tracker with patch request. See the following https://pagure.io/fedora-infrastructure/issue/10213[PR] for inspiration.

=== Pushing new changes out to the tftpboot server
To push out changes made to the `grub.cfg` the following playbook should be run, which requires `sysadmin-noc` group permissions:

----
sudo rbac-playbook groups/noc.yml -t 'tftp_server,dhcp_server'
----

On the `noc01` instance the `grub.cfg` file is located at `/var/lib/tftpboot/uefi/grub.cfg`

If particular changes to OS images for example, are required, they should be made on the `noc01` instance directly at `/var/lib/tftpboot/images/`. This will require users to be in the `sysadmin-noc` group.