The grub component manages the grub configuration.


The grub component manages the configuration of grub.

Most of the configuration is handled via the grubby tool (which supports grub2).

Some configuration like serial console settings and password however is done by modifying the grub configfile directly, which might not be safe under grub2.


Besides /software/component/grub, following resources are used:

  • /system/kernel/version for setting the default kernel
  • /hardware/console/serial for serial console configuration


  • A standard SL4 kernel with initrd image to be loaded.

    "/software/components/grub/kernels/0" =
          nlist("kernelpath", "/vmlinuz-2.6.9-22.0.1.EL",
                "kernelargs", "ro root=LABEL=/",
                "title", "Scientific Linux 4.2 / 2.6.9",
                "initrd", "/initrd-2.6.9-22.0.1.EL.img"

    This configuration produces the following entry in grub.conf (via grubby):

    title Scientific Linux 4.2 / 2.6.9
          kernel `/vmlinuz`-2.6.9-22.0.1.EL ro root=LABEL=/
          initrd `/initrd`-2.6.9-22.0.1.EL.img
  • A Xen 3 hypervisor with Linux 2.6 domain 0 kernel and initrd (via grubby).

    "/software/components/grub/kernels/1" =
          nlist("multiboot", "/xen-3.0.2-2.gz",
                "mbargs", "dom0_mem=400000",
                "title", "Xen 3 / XenLinux 2.6.16",
                "kernelpath", "/vmlinuz-2.6.16-xen3_86.1_rhel4.1",
                "kernelargs", "max_loop=128 root=/dev/hda2 ro",
                "initrd", "/initrd-2.6.16-xen3_86.1_rhel4.1"

    Produces the following entry in grub.conf:

    title Xen 3 / XenLinux 2.6.16
          kernel `/xen`-3.0.2-2.gz dom0_mem=400000 addthis
          module `/vmlinuz`-2.6.16-xen3_86.1_rhel4.1 max_loop=128 root=/dev/hda2 ro
          module `/initrd`-2.6.16-xen3_86.1_rhel4.1


  • grubby_args_options

    Given string args, split and convert into grubby commandline options to add and/or remove the arguments. Arguments prefixed with '-' are scheduled for removal If multiboot is true, generate multiboot commandline options

    Returns a list of options.

  • password

    Configure the grub password by editing the grub conf via filehandle grub_fh (a FileEditor instance, which is not closed in this method).

    Returns SUCCESS on succes, undef otherwise.

  • serial_console

    Configure the grub serial console settings (ttyS devices only) by editing the grub conf via filehandle grub_fh (a FileEditor instance, which is not closed in this method).

    Returns undef on failure, the console kernel commandline option (or empty string if none is to be configured) on success.

  • main_section_offset

    Given a grub config filehandle (a FileEditor instance), return the startposition of the main section i.e. after the header comments (if any).

  • grub_conf

    Edit grub configfile and return serial console kernel commandline option (if any).

  • grubby

    Run grubby with arraref args via CAF::Proces using the output method and return the output.

    Has following options

    • proc: return new Process instance with args (i.e. without execute/output)
    • success: run execute and return 1 on success, 0 on failure
    • keeps_state: pass keeps_state flag
  • current_default

    Return current full path of current default kernel.

  • set_default

    Set default kernel to new kernelpath and verify by (re)checking the default kernel.

    Returns success on success; on failure, return either

    • undef: setting default kernel returned non-zero exitcode
    • 0: setting default was succesful, but new default kernel is not expected kernel

    No errors are reported.

  • configure_default

    Configure the new default kernel to be new. If this fails and mbnew exists, try to set mbnew as default.

    If neither new nor mbnew are successful, report an error and revert to original.

  • kernel

    Configure boot entry using kernel hashref, the kernel prefix and optional serial console kernel commandline option cons.

    Any serial console settings in the kernelargs attribute is replaced by cons (when defined).

  • get_info

    Return info for default kernel as an arrayref of hashref

    Same kernel can have multiple entries.

  • default_options

    Configure kernel commandline options of default kernel

  • Configure

    Updates the grub.conf configuration file using grubby according to a list of kernels described in the profile.

    Sets the default kernel to that specified in /system/kernel/version.


    • serial console configuration specified in /hardware/console/serial.
    • multiboot loaders (most commonly used for configuration of Xen systems).

    Returns error in case of failure.