libvirt-bin 1.2.2-0ubuntu13 / usr / sbin / libvirt-migrate-qemu-disks

#!/bin/bash
#
# libvirt-migrate-qemu-disks
#
# Author: Jamie Strandboge <jamie@canonical.com>
# Copyright 2010 Canonical Ltd.
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License version 3,
#    as published by the Free Software Foundation.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

# This script probes qemu VMs and migrates the xml to the proper disk format
# if it is discovered that the disk file format is not raw.

# Since virsh can hang forever under certain circumstances, we need to account
# for this when migrating. This is accomplished by creating a stampdir and
# passing this to a backgrounded migrate_vm(). migrate_vm() will use this
# directory for its temporary files, and will remove the stampdir after the
# migration. The parent will poll for the stampdir's existance, and if it still
# exists after too long, it will remove it and kill all children.

set -e

debug() {
    test "$debug" = "yes" && echo "DEBUG: $*" >&2 || true
}

help() {
    cat << EOM
USAGE:
libvirt-migrate-qemu-disks -a
libvirt-migrate-qemu-disks -t TYPE vm1 vm2...

 -c		connect URI (defaults to qemu:///system)
 -a		probe all domains and migrate if necessary
 -t TYPE	migrate specified domains to disk format TYPE

You must specify domains when using '-t'. You may not specify both '-a' and
'-t'.
EOM
}

wait_for_libvirtd() {
    # Used to make sure libvirtd is responding
    virsh -c $connect capabilities >/dev/null 2>&1
    rm -f "$1"
}

migrate_vm() {
    dir="$1"
    vm="$2"
    format="$3"

    migrate=""
    found=
    in_disk=
    fn="$dir/$vm.xml"

    virsh -c $connect dumpxml "$vm" 2>/dev/null | while read line && test -d "$dir" ; do
        # This assumes the following format:
        # ...
        # <disk type='file' device='disk'>
        # <driver name='qemu' type='raw'/>
        # <source file='<disk>'/>
        # ...
        if [ -z "$in_disk" ] && echo "$line" | grep -q "<disk type='file'" ; then
            in_disk="yes"
        elif [ "$in_disk" = "yes" ] && [ "$found" != "yes" ]; then
            if echo "$line" | grep -q "<driver name='qemu' type='raw'/>" ; then
                found="yes"
                continue
            fi
            in_disk=
        elif [ "$found" = "yes" ]; then
            disk=`echo $line | cut -d "'" -f 2`
            if [ -n "$format" ]; then
                echo "<driver name='qemu' type='$format'/>" >> "$fn"
                migrate="yes"
            elif [ -r "$disk" ]; then
                probe_format=`LANG=C qemu-img info "$disk" | grep '^file format: ' | cut -d ' ' -f 3`
                if [ -n "$probe_format" ] && [ "$probe_format" != "raw" ]; then
                    echo "<driver name='qemu' type='$probe_format'/>" >> "$fn"
                    migrate="yes"
                fi
            else
                debug "'$disk' is not readble. Defaulting to 'raw'."
                echo "<driver name='qemu' type='raw'/>" >> "$fn"
            fi
            found=
            in_disk=
        fi
        echo "$line" >> "$fn"
        if [ "$line" = "</domain>" ]; then
            if [ "$migrate" = "yes" ]; then
                echo "Migrating '$vm'"
                virsh -c $connect define "$fn" >/dev/null
                debug "Using new xml:"
                debug `cat $fn`
            else
                debug "nothing to migrate"
            fi
            rm -rf "$dir"
            break
        fi
    done
}

connect="qemu:///system"
do_all=
debug=
while getopts adc:t: f ; do
    case "$f" in
        a) do_all="yes";;
        c) connect=$OPTARG;;
        d) debug="yes";;
        t) type=$OPTARG;;
        \?) help; exit 1;;
    esac
done
shift `expr $OPTIND - 1`

if [ -n "$type" ] && ! echo "$type" | egrep -q "^(raw|qcow2|qcow|cow|vdi|vmdk|vpc|cloop)$" ; then
    echo "'$type' is not supported. See 'man qemu-img' for details." >&2
    exit 1
fi

if [ "$connect" != "qemu:///system" ] && [ "$connect" != "qemu:///session" ]; then
    echo "Only qemu:///system and qemu:///session is supported" >&2
    exit 1
fi

xml_dir="/etc/libvirt/qemu"
if [ "$connect" = "qemu:///session" ]; then
    xml_dir="$HOME/.libvirt/qemu"
fi

vms=
if [ "$do_all" = "yes" ]; then
    # grab these from /etc/libvirt/qemu/*xml rather than virsh, since it
    # is a) the qemu driver that changed and b) virsh could hang
    cd "$xml_dir"
    vms=`ls -1 *.xml 2>/dev/null | sed 's/\.xml$//'`
    if [ -z "$vms" ]; then
        debug "no VMs to migrate"
        exit 0
    fi
    cd - >/dev/null
else
    vms="$*"
fi

if [ -z "$vms" ]; then
    help
    exit 1
elif [ -z "$do_all" ] && [ -z "$type" ]; then
    help
    exit 1
elif [ -n "$do_all" ] && [ -n "$type" ]; then
    help
    exit 1
fi

mypid="$$"
script=`basename $0`

# Alas, we need to make sure libvirtd is not only running, but responding to
# requests, otherwise migrate_vm() will fail for the first few VMs.
if [ "$connect" = "qemu:///system" ]; then
    pidfile="/var/run/libvirtd.pid"

    # Wait up to 10 seconds for libvirtd to come up before bailing.
    echo "Waiting up to 10 seconds for libvirtd to start... "
    count=0
    while [ ! -e "$pidfile" ]; do
        if [ $count -gt 100 ]; then
            break
        fi
        sleep 0.1
        count=$((count+1))
    done
    if [ ! -e "$pidfile" ]; then
        echo "Aborting. '$pidfile' does not exist. Is libvirtd running?"
        exit 1
    fi

    stamp=`mktemp`
    wait_for_libvirtd "$stamp" &

    # Wait up to 30 seconds for libvirtd to respond before bailing.
    echo "Waiting up to 30 seconds for libvirtd to respond to requests... "
    count=0
    while [ -e "$stamp" ]; do
        if [ $count -gt 300 ]; then
            break
        fi
        sleep 0.1
        count=$((count+1))
    done
    if [ -e "$stamp" ]; then
        echo "libvirtd is not responding. Aborting"
        kill `ps a | grep "/bin/sh .*libvirt-migrate-qemu-disks" | grep -v "$mypid" | awk '{print $1}'` 2>/dev/null || true
        rm -f "$stamp"
        exit 1
    fi
fi
echo "Checking domains defined in $xml_dir... "

for i in $vms ; do
    debug "checking $i"
    stampdir=`mktemp -d`

    migrate_vm "$stampdir" "$i" "$type" &

    count=0
    while [ -d "$stampdir" ]; do
        debug $count
        if [ $count -gt 100 ]; then
            break
        fi
        sleep 0.1
        count=$((count+1))
    done
    if [ -d "$stampdir" ]; then
        echo "migrate_vm \"$i\" is not responding. Aborting"
        kill `ps a | grep "/bin/sh .*libvirt-migrate-qemu-disks" | grep -v "$mypid" | awk '{print $1}'` 2>/dev/null || true
        rm -rf "$stampdir"
    fi
done

echo "Migration complete"