Chapter 14. Creating stateless images with RHEL image builder

Procedure

1. Build the customized RHEL image:

   $ image-builder build pxe-tar-xz --blueprint <blueprint-name>

   RHEL image builder creates the image in the current directory path:

   <os>-pxe-tar-xz-<architecture>.tar.xz

2. Extract the image components to your boot server. Locate the tarball file. If the tool created a directory, enter that directory to find the .tar.xz file. Then, extract it to your TFTP root:

   $ sudo tar -xJf <image-name>.tar.xz -C /var/lib/tftpboot/rhel-pxe/

Procedure

1. Prepare the TFTP server by placing the vmlinuz, initrd.img, and rootfs.img files in the root directory of your TFTP server.
2. Modify the grub.cfg configuration, replacing the HTTP-SERVER placeholder with the actual URL of your HTTP server.

3. Serve the rootfs.img by using HTTP inside the directory containing the rootfs.img file:

   $ python3 -m http.server 8000

Procedure

1. Create the rootfs CPIO archive:

   $ echo rootfs.img | cpio -c --quiet -L -o > rootfs.cpio

2. Concatenate the initrd.img and rootfs.cpio images:

   $ cat initrd.img rootfs.cpio > combined.img

3. Boot the system by using the resulting combined.img file as your initrd in your PXE configuration.

   Note

   Using a combined image significantly increases the initial network payload. Because the entire root filesystem is transferred during the PXE phase, ensure your network bandwidth can handle the increased traffic, especially when booting multiple systems simultaneously.