Логика кластера Виртуальных машин

virsh create /patchtoconfig

virsh start домен

virsh destroy домен #но сначало было бы не плохо попытаться остановить машину shutdown
virsh undefined домен

t -e
SELF=10.1.1.1
PEER=10.1.1.2
if [ $(hostname) = xen2 ]; then
    SELF=10.1.1.2
    PEER=10.1.1.1
fi
SSH_OPTS="-o ConnectTimeout=15"
configfile=$1
command=$2
function usage {
    echo "Usage: $0 CFG start|stop|status"
    exit 1
}
if [ ! -r "$configfile" ]; then
    usage
fi
. $configfile
function is_alive {
    #xm list | grep -q "^$1 "
    xm list $1 >/dev/null 2>&1
}
function safe_to_migrate {
    case "$(drbdadm cstate $DRBD)" in
    Connected|SyncSource|SyncTarget)
        return 0
        ;;
    *)
        return 1
        echo "$DRBD is disconnected, NOT safe to migrate"
        ;;
    esac
}
function prepare_migration {
    echo "Preparing for migration:"
    ssh $SSH_OPTS $PEER "drbdadm primary $DRBD && vgscan && vgchange -a y $LVM";
    if [ "$EXTRA_DRBD" ]; then
        ssh $SSH_OPTS $PEER "drbdadm primary $EXTRA_DRBD"
    fi
}
function dom_names {
    ls $CFGDIR | egrep '^[0-9a-z]+$'
}
function start_disk {
    echo "Starting volumes:"
    drbdadm primary $DRBD
    vgscan
    vgchange -a y $LVM
    if [ "$EXTRA_DRBD" ]; then
        drbdadm primary $EXTRA_DRBD
    fi
}
function stop_disk {
    echo "Stopping volumes:"
    vgchange -a n $LVM || true
    drbdadm secondary $DRBD || true
    if [ "$EXTRA_DRBD" ]; then
        drbdadm secondary $EXTRA_DRBD || true
    fi
}
function update_mac_cache {
    arp -d $name >/dev/null 2>&1 || true
    ping -c1 -w1 $name >/dev/null 2>&1 || true
}
function start_domains {
    start_disk
    local name
    for name in $(dom_names); do
        echo -n "Starting $name: "
        if is_alive $name; then
            echo "already running."
        else
            if safe_to_migrate &&
                    ssh $SSH_OPTS $PEER "xm migrate --live $name $SELF"; then
                update_mac_cache
                echo "migrated back."
            else
                xm create -q $CFGDIR/$name
                echo "created."
                sleep 2
            fi
        fi
    done
    if safe_to_migrate; then
        ssh $SSH_OPTS $PEER "vgchange -a n $LVM; drbdadm secondary $DRBD" || true
        if [ "$EXTRA_DRBD" ]; then
            ssh $SSH_OPTS $PEER "drbdadm secondary $EXTRA_DRBD" || true
        fi
    fi
    touch $LOCKFILE
}
function stop_domains {
    rm -f $LOCKFILE
    local migration
    if safe_to_migrate && prepare_migration; then
        migration="OK"
    else
        migration="NG"
    fi
    local name
    for name in $(dom_names); do
        echo -n "Stopping $name: "
        if ! is_alive $name; then
            echo "not running."
        else
            if [ $migration = "OK" ] && xm migrate --live $name $PEER; then
                update_mac_cache
                echo "migrated."
            else
                xm shutdown $name
                echo "shutting down..."
            fi
        fi
    done
    echo -n "Waiting for shutdown complete..."
    local n=0
    while [ $n -lt 60 ]; do
        alive=0
        for name in $(dom_names); do
            if is_alive $name; then
                alive=1
            fi
        done
        if [ $alive = 0 ]; then
            echo "ok"
            break
        fi
        echo -n "."
        sleep 1
        n=$(expr $n + 1)
    done
    for name in $(dom_names); do
        if is_alive $name; then
            echo "Destroying $name"
            xm destroy $name
        fi
    done
    stop_disk
}
function print_status {
    if [ -f $LOCKFILE ]; then
        echo "OK"
    else
        echo "Stopped"
        exit 1
    fi
}
case $command in
start)
    start_domains
    ;;
stop)
    stop_domains
    ;;
status)
    print_status
    ;;
*)
    usage
    ;;
esac