#!/bin/sh
#
# External STONITH module for a libvirt managed hypervisor (kvm/Xen).
# Uses libvirt as a STONITH device to control guest.
#
# Copyright (c) 2010 Holger Teutsch <holger.teutsch@web.de>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# Further, this software is distributed without any warranty that it is
# free of the rightful claim of any third person regarding infringement
# or the like.  Any license provided herein, whether implied or
# otherwise, applies only to this software file.  Patent licenses, if
# any, provided herein do not apply to combinations of this program with
# other software, or any other product whatsoever.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#

# start a domain
libvirt_start() {
    out=$($VIRSH -c $hypervisor_uri start $domain_id 2>&1)
    if [ $? -eq 0 ]
    then
        ha_log.sh notice "Domain $domain_id was started"
        return 0
    fi

    $VIRSH -c $hypervisor_uri dominfo $domain_id 2>&1 |
        egrep -q '^State:.*(running|idle)|already active'
    if [ $? -eq 0 ]
    then
        ha_log.sh notice "Domain $domain_id is already active"
        return 0
    fi

    ha_log.sh err "Failed to start domain $domain_id"
    ha_log.sh err "$out"
    return 1
}
# reboot a domain
# return
#   0: success
#   1: error
libvirt_reboot() {
    local rc out
    out=$($VIRSH -c $hypervisor_uri reboot $domain_id 2>&1)
    rc=$?
    if [ $rc -eq 0 ]
    then
        ha_log.sh notice "Domain $domain_id was rebooted"
        return 0
    fi
    ha_log.sh err "Failed to reboot domain $domain_id (exit code: $rc)"
    ha_log.sh err "$out"
    return 1
}

# stop a domain
# return
#   0: success
#   1: error
#   2: was already stopped
libvirt_stop() {
    out=$($VIRSH -c $hypervisor_uri destroy $domain_id 2>&1)
    if [ $? -eq 0 ]
    then
        ha_log.sh notice "Domain $domain_id was stopped"
        return 0
    fi

    $VIRSH -c $hypervisor_uri dominfo $domain_id 2>&1 |
        egrep -q '^State:.*shut off|not found|not running'
    if [ $? -eq 0 ]
    then
        ha_log.sh notice "Domain $domain_id is already stopped"
        return 2
    fi

    ha_log.sh err "Failed to stop domain $domain_id"
    ha_log.sh err "$out"
    return 1
}

# get status of stonith device (*NOT* of the domain).
# If we can retrieve some info from the hypervisor
# the stonith device is OK.
libvirt_status() {
    out=$($VIRSH -c $hypervisor_uri version 2>&1)
    if [ $? -eq 0 ]
    then
        return 0
    fi

    ha_log.sh err "Failed to get status for $hypervisor_uri"
    ha_log.sh err "$out"
    return 1
}

# check config and set variables
# does not return on error
libvirt_check_config() {
    VIRSH=`which virsh 2>/dev/null`

    if [ ! -x "$VIRSH" ]
    then
        ha_log.sh err "virsh not installed"
        exit 1
    fi

    if [ -z "$hostlist" -o -z "$hypervisor_uri" ]
    then
        ha_log.sh err "hostlist or hypervisor_uri missing; check configuration"
        exit 1
    fi

    case "$reset_method" in
    power_cycle|reboot) : ;;
    *)
        ha_log.sh err "unrecognized reset_method: $reset_method"
        exit 1
    ;;
    esac
}

# set variable domain_id for the host specified as arg
libvirt_set_domain_id ()
{
    for h in $hostlist
    do
        case $h in
            $1:*)
            domain_id=`expr $h : '.*:\(.*\)'`
            return
            ;;

            $1)
            domain_id=$1
            return
        esac
    done

    ha_log.sh err "Should never happen: Called for host $1 but $1 is not in $hostlist."
    exit 1
}

libvirt_info() {
cat << LVIRTXML
<parameters>
<parameter name="hostlist" unique="1" required="1">
<content type="string" />
<shortdesc lang="en">
List of hostname[:domain_id]..
</shortdesc>
<longdesc lang="en">
List of controlled hosts: hostname[:domain_id]..
The optional domain_id defaults to the hostname. 
</longdesc>
</parameter>

<parameter name="hypervisor_uri" required="1">
<content type="string" />
<shortdesc lang="en">
Hypervisor URI
</shortdesc>
<longdesc lang="en">
URI for connection to the hypervisor.
driver[+transport]://[username@][hostlist][:port]/[path][?extraparameters]
e.g.
qemu+ssh://my_kvm_server.mydomain.my/system   (uses ssh for root)
xen://my_kvm_server.mydomain.my/              (uses TLS for client)

virsh must be installed (e.g. libvir-client package) and access control must
be configured for your selected URI.
</longdesc>
</parameter>

<parameter name="reset_method" required="0">
<content type="string" default="power_cycle"/>
<shortdesc lang="en">
How to reset a guest.
</shortdesc>
<longdesc lang="en">
A guest reset may be done by a sequence of off and on commands
(power_cycle) or by the reboot command. Which method works
depend on the hypervisor and guest configuration management.
</longdesc>
</parameter>
</parameters>
LVIRTXML
exit 0
}

#############
# Main code #
#############

# don't fool yourself when testing with stonith(8)
# and transport ssh
unset SSH_AUTH_SOCK

# support , as a separator as well
hostlist=`echo $hostlist| sed -e 's/,/ /g'`

reset_method=${reset_method:-"power_cycle"}

case $1 in
    gethosts)
    hostnames=`echo $hostlist|sed -e 's/:[^ ]*//g'`
    for h in $hostnames
    do
        echo $h
    done
    exit 0
    ;;

    on)
    libvirt_check_config
    libvirt_set_domain_id $2

    libvirt_start
    exit $?
    ;;

    off)
    libvirt_check_config
    libvirt_set_domain_id $2

    libvirt_stop
    [ $? = 1 ] && exit 1
    exit 0
    ;;

    reset)
    libvirt_check_config
    libvirt_set_domain_id $2

    if [ "$reset_method" = "power_cycle" ]; then
        libvirt_stop
        [ $? = 1 ] && exit 1
        sleep 2
        libvirt_start
    else
        libvirt_reboot
    fi
    exit $?
    ;;

    status)
    libvirt_check_config
    libvirt_status
    exit $?
    ;;

    getconfignames)
    echo "hostlist hypervisor_uri reboot_method"
    exit 0
    ;;

    getinfo-devid)
    echo "libvirt STONITH device"
    exit 0
    ;;

    getinfo-devname)
    echo "libvirt STONITH external device"
    exit 0
    ;;

    getinfo-devdescr)
    echo "libvirt-based host reset for Xen/KVM guest domain through hypervisor"
    exit 0
    ;;

    getinfo-devurl)
    echo "http://libvirt.org/uri.html http://linux-ha.org/wiki"
    exit 0
    ;;

    getinfo-xml)
    libvirt_info
    echo 0;
    ;;

    *)
    exit 1
    ;;
esac

# vi:et:ts=4:sw=4