Re: /etc/grub.d/09-xen for generating grub.cfg for hypervisor boot entries.

[listmail <listmail@triad.rr.com>]

Yes that should do it and no corresponding boot/config-$(uname -r) means 
nothing will be generated for the respective kernel.  There could also 
be a check for CONFIG_XEN=y to support Xenlinux kernels.  That entry 
should not exist in pvops .config so a special menu entry tag could also 
be generated depicting kernel type if desirable.  Those are things I 
might add in afterwards if you are not interested in them.

Bruce Edge wrote:
> Perhaps grepping for CONFIG_XEN_DOM0=y in the boot/config-XX would 
> validate the dom0 kernel compatibility better then looking for -xen in 
> the name.
>
> -Bruce
>
> -Bruce
>
>
> On Wed, May 19, 2010 at 10:07 AM, Richie <listmail@triad.rr.com 
> <mailto:listmail@triad.rr.com>> wrote:
>
>     Perhaps it goes without saying, but I don't think my suggestion
>     for a xen in the image name check will be an accurate solution for
>     someone that does not roll their own kernels.  I always know that
>     my kernels have xen in the name when they are pvops/dom0 capable
>     and sxen when they are Xenlinux.  Also, technically, for Xenlinux
>     kernels, grub should not be generating bare metal boot entries.
>
>     If anything, this could also be used as a basis for a script that
>     generates an initial 40_custom file.  That can then be hand edited
>     before running update-grub.
>
>
>     Bruce Edge wrote:
>
>         Good points all. Will incorporate, retest and repost the
>         resultant script.
>
>         Thanks
>
>         -Bruce
>
>
>         On Tue, May 18, 2010 at 5:24 PM, Richie <listmail@triad.rr.com
>         <mailto:listmail@triad.rr.com> <mailto:listmail@triad.rr.com
>         <mailto:listmail@triad.rr.com>>> wrote:
>
>            I like the idea myself and I haven't seen anything in the
>         wiki's
>            other than manual creation steps.
>
>            Just an opinion here, but why not use "dummy=dummy" as
>         opposed to
>            first parameter duplication?  My understanding is that dummy is
>            used to avoid this same bug.  Either way we it avoids having to
>            hardcode root= into the kernel cmdline .config parameter :)  I
>            don't know if parameter duplication would break things when the
>            bug is fixed or not, but the dummy parameter shouldn't.  I also
>            think it might be viewed as something more familiar,
>         perhaps self
>            explanatory, whereas the parameter duplication may cause
>         confusion.
>
>            I skimmed the code and have not tested it.  I don't see
>         that it is
>            specifically trying to ensure that the kernel is Xenlinux or
>            pvops...  Not that I know of a proper way to do such or if its
>            even pratical.  Aren't most kernels now pvops (thus
>         bootable under
>            xen) but not necessarily dom0 capable?  I think a spin on this
>            would be if one wanted to limit the Xen entries to kernels with
>            "xen" (ie. --append-to-version) in the name.  Perhaps the code
>            would change as follows?
>
>            <snip>
>            list=`for i in /boot/vmlinu[xz]-*xen* /vmlinu[xz]-*xen* ; do
>
>                  if grub_file_is_not_garbage "$i" ; then echo -n "$i "
>         ; fi
>                done`
>            <snip>
>
>
>
>            Bruce Edge wrote:
>
>                If this has already been done, please forgive me.
>         However, if
>                not, I'd like to submit this as a mechanism for
>         generating a
>                bootable grub2 stanza for hypervisors.
>
>                As the /etc/grub.d/* files rely on defaults in
>                /etc/default/grub, I added the following Xen specific
>         variable:
>
>                GRUB_CMDLINE_XEN_DEFAULT="console=com1 115200,8n1
>                dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin=true
>                iommu=1,passthrough,no-intremap loglvl=all loglvl_guest=all
>                loglevl=10 debug acpi=force apic=on apic_verbosity=verbose
>                numa=on"
>
>                The script itself is a hacked version of the10-linux that
>                comes with grub2. This is 09-xen so it places it's boot
>                entries ahead of the non-xen entries.
>                The resulting grub.cfg entry looks like:
>
>                ### BEGIN /etc/grub.d/09_xen ###
>                 insmod lvm
>                 set root=(system-dom0_0)
>                menuentry "Xen osa-dom0 6.0.13-05, linux 2.6.32.12" {
>                       multiboot /boot/xen.gz /boot/xen.gz console=com1
>                115200,8n1 dom0_mem=512M dom0_max_vcpus=1
>         dom0_vcpus_pin=true
>                iommu=1,passthrough,no-intremap loglvl=all loglvl_guest=all
>                loglevl=10 debug acpi=force apic=on
>         apic_verbosity=verbose numa=on
>                       module /boot/vmlinuz-2.6.32.12
>         /boot/vmlinuz-2.6.32.12
>                root=UUID=a3764d7d-6292-4f08-8ece-480e54c77229  ro
>                earlyprintk=xen loglevel=10 debug acpi=force
>         console=hvc0,115200n8
>                       module /boot/initrd.img-2.6.32.12
>                /boot/initrd.img-2.6.32.12
>                }
>                ### END /etc/grub.d/09_xen ###
>
>                Note the duplication of the first params. I believe
>         there's a
>                bug that drops the 1st param so this could be changed
>         later.
>
>                #! /bin/sh -e
>
>                prefix=/usr
>                exec_prefix=${prefix}
>                libdir=${exec_prefix}/lib
>                . ${libdir}/grub/update-grub_lib
>
>                if [ "x${GRUB_DISTRIBUTOR}" = "x" ] ; then
>                 OS=GNU/Linux
>                else
>                 OS="${GRUB_DISTRIBUTOR}"
>                fi
>
>                # Source grub defaults
>                . /etc/default/grub
>
>                # loop-AES arranges things so that /dev/loop/X can be
>         our root
>                device, but
>                # the initrds that Linux uses don't like that.
>                case ${GRUB_DEVICE} in
>                 /dev/loop/*|/dev/loop[0-9])
>                   GRUB_DEVICE=`losetup ${GRUB_DEVICE} | sed -e
>                "s/^[^(]*(\([^)]\+\)).*/\1/"`
>                 ;;
>                esac
>
>                if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [
>                "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
>                   || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}"
>         ; then
>                 LINUX_ROOT_DEVICE=${GRUB_DEVICE}
>                else
>                 LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
>                fi
>
>                test_gt ()
>                {
>                 local a=`echo $1 | sed -e
>              
>          "s,.*/vmlinu[zx]-,,g;s/[._-]\(pre\|rc\|test\|git\|old\)/~\1/g"`
>                 local b=`echo $2 | sed -e
>              
>          "s,.*/vmlinu[zx]-,,g;s/[._-]\(pre\|rc\|test\|git\|old\)/~\1/g"`
>                 if [ "x$b" = "x" ] ; then
>                   return 0
>                 fi
>                 dpkg --compare-versions "$a" gt "$b"
>                 return $?
>                }
>
>                find_latest ()
>                {
>                 local a=""
>                 for i in $@ ; do
>                   if test_gt "$i" "$a" ; then
>                     a="$i"
>                   fi
>                 done
>                 echo "$a"
>                }
>
>                list=`for i in /boot/vmlinu[xz]-* /vmlinu[xz]-* ; do
>                       if grub_file_is_not_garbage "$i" ; then echo -n
>         "$i " ; fi
>                     done`
>
>                while [ "x$list" != "x" ] ; do
>                 linux=`find_latest $list`
>                 echo "Found linux image: $linux" >&2
>                 basename=`basename $linux`
>                 dirname=`dirname $linux`
>                 rel_dirname=`make_system_path_relative_to_its_root
>         $dirname`
>                 version=`echo $basename | sed -e "s,^[^0-9]*-,,g"`
>                 alt_version=`echo $version | sed -e "s,\.old$,,g"`
>                 linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"
>
>                 initrd=
>                 for i in "initrd.img-${version}" "initrd-${version}.img" \
>                          "initrd.img-${alt_version}"
>                "initrd-${alt_version}.img"; do
>                   if test -e "${dirname}/${i}" ; then
>                     initrd="$i"
>                     break
>                   fi
>                 done
>                 if test -n "${initrd}" ; then
>                   echo "Found initrd image: ${dirname}/${initrd}" >&2
>                 else
>                   # "UUID=" magic is parsed by initrds.  Since there's no
>                initrd, it can't work here.
>                   linux_root_device_thisversion=${GRUB_DEVICE}
>                 fi
>
>                 cat << EOF
>                 insmod lvm
>                 set root=(system-dom0_0)
>                menuentry "Xen ${OS}, linux ${version}" {
>                       multiboot /boot/xen.gz /boot/xen.gz
>                $GRUB_CMDLINE_XEN_DEFAULT
>                       module ${rel_dirname}/${basename}
>                ${rel_dirname}/${basename}
>                root=${linux_root_device_thisversion}
>         $GRUB_CMDLINE_LINUX_DEFAULT
>                EOF
>                 if test -n "${initrd}" ; then
>                   cat << EOF
>                       module ${rel_dirname}/${initrd}
>         ${rel_dirname}/${initrd}
>                EOF
>                 fi
>                 cat << EOF
>                }
>                EOF
>
>                 list=`echo $list | tr ' ' '\n' | grep -vx $linux | tr
>         '\n' ' '`
>                done
>
>
>                -Bruce
>              
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>
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