help: |
    Create an initramfs for a system by taking an existing system and
    converting it to the appropriate format.

    The system must have a `/init` executable as the userland entry-point.
    This can have a different path, if `rdinit=$path` is added to
    the kernel command line. This can be added to the `rawdisk`,
    `virtualbox-ssh` and `kvm` write extensions with the `KERNEL_CMDLINE`
    option.

    It is possible to use a ramfs as the final rootfs without a `/init`
    executable, by setting `root=/dev/mem`, or `rdinit=/sbin/init`,
    but this is beyond the scope for the `initramfs.write` extension.

    The intended use of initramfs.write is to be part of a nested
    deployment, so the parent system has an initramfs stored as
    `/boot/initramfs.gz`. See the following example:

        name: initramfs-test
        kind: cluster
        systems:
        - morph: minimal-system-x86_64-generic
          deploy:
            system:
              type: rawdisk
              location: initramfs-system-x86_64.img
              DISK_SIZE: 1G
              HOSTNAME: initramfs-system
              INITRAMFS_PATH: boot/initramfs.gz
          subsystems:
          - morph: initramfs-x86_64
            deploy:
              initramfs:
                type: initramfs
                location: boot/initramfs.gz