File xend-domain-lock.patch of Package xen
Index: xen-4.0.2-testing/tools/examples/xend-config.sxp
===================================================================
--- xen-4.0.2-testing.orig/tools/examples/xend-config.sxp
+++ xen-4.0.2-testing/tools/examples/xend-config.sxp
@@ -308,6 +308,65 @@
# device assignment could really work properly even after we do this.
#(pci-passthrough-strict-check yes)
+# Domain Locking
+# In a multihost environment, domain locking prevents simultaneously
+# running a domain on more than one host.
+#
+# If enabled, xend will execute a external lock utility (defined below)
+# on each domain start and stop event. Disabled by default. Set to yes
+# to enable domain locking.
+#
+#(xend-domain-lock no)
+
+# Path where domain lock is stored if xend-domain-lock is enabled.
+# Note: This path must be accessible to all VM Servers participating
+# in domain locking, e.g. by specifying a shared mount point.
+# Lock is placed in /<xend-domain-lock-path>/<domain-uuid>.
+# Default is /var/lib/xen/images/vm_locks/
+#
+#(xend-domain-lock-path /var/lib/images/vm_locks)
+
+# External locking utility called by xend for acquiring/releasing
+# domain lock. By default /etc/xen/scripts/domain-lock will be used
+# if xend-domain-lock is set to yes. Set to path of custom locking
+# utility to override the default.
+#
+# Synopsis of lock-util:
+# lock-util [-l|-u] -n <vm name> -i <vm uuid> -p <physical host> path"
+# -l Acquire (create) lock
+# -u Remove lock
+# -n vm-name Name of domain
+# -i vm-id Id or UUID of domain
+# -p phy-host Name of physical host (dom0)
+# path /<xend-domain-lock-path>/<vm-uuid>
+# Return 0 on success, non-zero on error.
+#
+# lock-util [-s] path"
+# -s Lock status. If lock is acquired, print any contents
+# on stdout and return 0. Return non-zero if lock is
+# available.
+# path /<xend-domain-lock-path>/<vm-uuid>
+# If lock is acquired, print any contents on stdout and return 0.
+# Return non-zero if lock is available.
+#
+# Default lock-util behavior:
+# On domain start event, domain-lock will create and flock(1)
+# /<xend-domain-lock-path>/<vm-uuid>/lock. Every two seconds it
+# will write <vm-name>, <vm-id>, <vm-host>, and <tick> to the lock.
+# <tick> is running counter.
+# On domain stop event, domain-lock will unlock and remove
+# /<xend-domain-lock-path>/<vm-uuid>/lock.
+#
+# Note: If xend-domain-lock-path is a cluster-unaware file system,
+# administrator intervention may be required to remove stale
+# locks. Consider two hosts using NFS for xend-domain-lock-path
+# when HostA, running vm1, crashes. HostB could not acquire a
+# lock for vm1 since the NFS server holds an exclusive lock
+# acquired by HostA. The lock file must be manually removed
+# before starting vm1 on HostA.
+#
+#(xend-domain-lock-utility domain-lock)
+
# If we have a very big scsi device configuration, start of xend is slow,
# because xend scans all the device paths to build its internal PSCSI device
# list. If we need only a few devices for assigning to a guest, we can reduce
Index: xen-4.0.2-testing/tools/python/xen/xend/XendDomainInfo.py
===================================================================
--- xen-4.0.2-testing.orig/tools/python/xen/xend/XendDomainInfo.py
+++ xen-4.0.2-testing/tools/python/xen/xend/XendDomainInfo.py
@@ -32,11 +32,12 @@ import re
import copy
import os
import stat
+import shutil
import traceback
from types import StringTypes
import xen.lowlevel.xc
-from xen.util import asserts, auxbin
+from xen.util import asserts, auxbin, mkdir
from xen.util.blkif import parse_uname
import xen.util.xsm.xsm as security
from xen.util import xsconstants
@@ -469,6 +470,7 @@ class XendDomainInfo:
if self._stateGet() in (XEN_API_VM_POWER_STATE_HALTED, XEN_API_VM_POWER_STATE_SUSPENDED, XEN_API_VM_POWER_STATE_CRASHED):
try:
+ self.acquire_running_lock();
XendTask.log_progress(0, 30, self._constructDomain)
XendTask.log_progress(31, 60, self._initDomain)
@@ -2987,6 +2989,11 @@ class XendDomainInfo:
self._stateSet(DOM_STATE_HALTED)
self.domid = None # Do not push into _stateSet()!
+
+ try:
+ self.release_running_lock()
+ except:
+ log.exception("Failed to release domain lock.")
finally:
self.refresh_shutdown_lock.release()
@@ -4499,6 +4506,74 @@ class XendDomainInfo:
def has_device(self, dev_class, dev_uuid):
return (dev_uuid in self.info['%s_refs' % dev_class.lower()])
+ # Return name of host contained in lock file.
+ def get_lock_host(self, path):
+ fin = os.popen(xoptions.get_xend_domain_lock_utility() + \
+ ' -s ' + path, 'r')
+ hostname = "unknown"
+
+ try:
+ tokens = fin.readline().split()
+ for token in tokens:
+ item = token.split('=')
+ if item[0] == 'host':
+ hostname = item[1]
+ return hostname
+ finally:
+ fin.close()
+
+ # Acquire a lock for the domain. No-op if domain locking is turned off.
+ def acquire_running_lock(self):
+ if not xoptions.get_xend_domain_lock():
+ return
+
+ log.debug("Acquiring lock for domain %s" % self.info['name_label'])
+ path = xoptions.get_xend_domain_lock_path()
+ path = os.path.join(path, self.get_uuid())
+
+ try:
+ if not os.path.exists(path):
+ mkdir.parents(path, stat.S_IRWXU)
+ except:
+ log.exception("%s could not be created." % path)
+ raise XendError("%s could not be created." % path)
+
+ status = os.system('%s -l -p %s -n %s -i %s %s' % \
+ (xoptions.get_xend_domain_lock_utility(), \
+ XendNode.instance().get_name(), \
+ self.info['name_label'], \
+ self.info['uuid'], \
+ path))
+ if status != 0:
+ log.debug("Failed to aqcuire lock: status = %d" % status)
+ raise XendError("The VM is locked and appears to be running on host %s." % self.get_lock_host(path))
+
+ # Release lock for domain. No-op if domain locking is turned off.
+ def release_running_lock(self, name = None):
+ if not xoptions.get_xend_domain_lock():
+ return
+
+ dom_name = self.info['name_label']
+ if name:
+ dom_name = name
+ log.debug("Releasing lock for domain %s" % dom_name)
+
+ path = xoptions.get_xend_domain_lock_path()
+ path = os.path.join(path, self.get_uuid())
+ status = os.system('%s -u -p %s -n %s -i %s %s' % \
+ (xoptions.get_xend_domain_lock_utility(), \
+ XendNode.instance().get_name(), \
+ dom_name, \
+ self.info['uuid'], \
+ path))
+ if status != 0:
+ log.exception("Failed to release lock: status = %s" % status)
+ try:
+ if len(os.listdir(path)) == 0:
+ shutil.rmtree(path)
+ except:
+ log.exception("Failed to remove unmanaged directory %s." % path)
+
def __str__(self):
return '<domain id=%s name=%s memory=%s state=%s>' % \
(str(self.domid), self.info['name_label'],
Index: xen-4.0.2-testing/tools/python/xen/xend/XendOptions.py
===================================================================
--- xen-4.0.2-testing.orig/tools/python/xen/xend/XendOptions.py
+++ xen-4.0.2-testing/tools/python/xen/xend/XendOptions.py
@@ -154,6 +154,17 @@ class XendOptions:
use loose check automatically if necessary."""
pci_dev_assign_strict_check_default = True
+ """Default for the flag indicating whether xend should create
+ a lock file for domains when they are started."""
+ xend_domain_lock = 'no'
+
+ """Default domain lock storage path."""
+ xend_domain_lock_path_default = '/var/lib/xen/images/vm_locks'
+
+ """Default script to acquire/release domain lock"""
+ xend_domain_lock_utility = auxbin.scripts_dir() + "/domain-lock"
+
+
def __init__(self):
self.configure()
@@ -401,6 +412,24 @@ class XendOptions:
else:
return None
+ def get_xend_domain_lock(self):
+ """Get the flag indicating whether xend should create a lock file
+ for domains when they are started."""
+ return self.get_config_bool("xend-domain-lock", self.xend_domain_lock)
+
+ def get_xend_domain_lock_path(self):
+ """ Get the path for domain lock storage
+ """
+ return self.get_config_string("xend-domain-lock-path", self.xend_domain_lock_path_default)
+
+ def get_xend_domain_lock_utility(self):
+ s = self.get_config_string('xend-domain-lock-utility')
+
+ if s:
+ return os.path.join(auxbin.scripts_dir(), s)
+ else:
+ return self.xend_domain_lock_utility
+
def get_vnc_tls(self):
return self.get_config_string('vnc-tls', self.xend_vnc_tls)
Index: xen-4.0.2-testing/tools/python/xen/xend/XendCheckpoint.py
===================================================================
--- xen-4.0.2-testing.orig/tools/python/xen/xend/XendCheckpoint.py
+++ xen-4.0.2-testing/tools/python/xen/xend/XendCheckpoint.py
@@ -133,6 +133,8 @@ def save(fd, dominfo, network, live, dst
dominfo.shutdown('suspend')
dominfo.waitForSuspend()
if line in ('suspend', 'suspended'):
+ if checkpoint == False:
+ dominfo.release_running_lock(domain_name)
dominfo.migrateDevices(network, dst, DEV_MIGRATE_STEP2,
domain_name)
log.info("Domain %d suspended.", dominfo.getDomid())
@@ -410,6 +412,7 @@ def restore(xd, fd, dominfo = None, paus
if not paused:
dominfo.unpause()
+ dominfo.acquire_running_lock()
return dominfo
except Exception, exn:
dominfo.destroy()
Index: xen-4.0.2-testing/tools/hotplug/Linux/Makefile
===================================================================
--- xen-4.0.2-testing.orig/tools/hotplug/Linux/Makefile
+++ xen-4.0.2-testing/tools/hotplug/Linux/Makefile
@@ -20,6 +20,7 @@ XEN_SCRIPTS += vtpm vtpm-delete
XEN_SCRIPTS += xen-hotplug-cleanup
XEN_SCRIPTS += external-device-migrate
XEN_SCRIPTS += vscsi
+XEN_SCRIPTS += domain-lock vm-monitor
XEN_SCRIPT_DATA = xen-script-common.sh locking.sh logging.sh
XEN_SCRIPT_DATA += xen-hotplug-common.sh xen-network-common.sh vif-common.sh
XEN_SCRIPT_DATA += block-common.sh vtpm-common.sh vtpm-hotplug-common.sh
Index: xen-4.0.2-testing/tools/hotplug/Linux/domain-lock
===================================================================
--- /dev/null
+++ xen-4.0.2-testing/tools/hotplug/Linux/domain-lock
@@ -0,0 +1,83 @@
+#!/bin/bash
+
+basedir=$(dirname "$0")
+
+usage() {
+ echo "usage: domain-lock [-l|-u] -n <vm name> -i <vm uuid> -p <physical host> path"
+ echo "usage: domain-lock [-s] path"
+ echo ""
+ echo "-l lock"
+ echo "-u unlock"
+ echo "-s status (default)"
+ echo "-n Virtual Machine name"
+ echo "-i Virtual Machine Id or UUID"
+ echo "-p Virtual Machine Server (physical host) name"
+ echo "path A per-VM, unique location where external lock will be managed"
+ exit 1
+}
+
+remove_lock(){
+ local path=$1/lock
+ local name=$2
+
+ pid=`ps -efwww | grep vm-monitor | grep $name | awk '{print $2}'`
+ if [ -n "$pid" ]; then
+ kill $pid
+ rm -f $path
+ fi
+}
+
+get_status(){
+ local path=$1/lock
+ [ -f $path ] || exit 1
+
+ rc=`flock -xn $path /bin/true`
+ cat $path
+ exit $rc
+}
+
+mode="status"
+
+while getopts ":lusn:i:p:" opt; do
+ case $opt in
+ l )
+ mode="lock"
+ ;;
+ u )
+ mode="unlock"
+ ;;
+ s )
+ mode="status"
+ ;;
+ p )
+ vm_host=$OPTARG
+ ;;
+ n )
+ vm_name=$OPTARG
+ ;;
+ i )
+ vm_uuid=$OPTARG
+ ;;
+ \? )
+ usage
+ ;;
+ esac
+done
+
+shift $(($OPTIND - 1))
+vm_path=$1
+
+case $mode in
+ lock )
+ [ -z "$vm_path" ] || [ -z "$vm_name" ] || [ -z "$vm_uuid" ] || [ -z "$vm_host" ] && usage
+ $basedir/set-lock $vm_path $vm_name $vm_uuid $vm_host
+ ;;
+ unlock )
+ [ -z "$vm_path" ] || [ -z "$vm_name" ] || [ -z "$vm_uuid" ] || [ -z "$vm_host" ] && usage
+ remove_lock $vm_path $vm_name $vm_uuid $vm_host
+ ;;
+ status )
+ [ -z "$vm_path" ] && usage
+ get_status $vm_path
+ ;;
+esac
Index: xen-4.0.2-testing/tools/hotplug/Linux/vm-monitor
===================================================================
--- /dev/null
+++ xen-4.0.2-testing/tools/hotplug/Linux/vm-monitor
@@ -0,0 +1,41 @@
+#!/bin/bash
+
+basedir=$(dirname "$0")
+HA_TICK=2
+
+monitor() {
+ local path=$1
+ local name=$2
+ local uuid=$3
+ local host=$4
+ local count=0
+ path=$path/lock
+
+ while :
+ do
+ echo "name=$name uuid=$uuid host=$host count=$count" > $path
+ count=$(($count+1))
+ sleep $HA_TICK
+ done&
+}
+
+create_lock() {
+ local path=$1/lock
+ local rc=0
+
+ [ -f $path ] || touch $path
+ flock -x -w $HA_TICK $path $basedir/vm-monitor $*
+ rc=$?
+ if [ $rc -eq 1 ]; then
+ echo `cat $path`
+ exit 1
+ else
+ exit $rc
+ fi
+}
+
+if [ $0 = "$basedir/set-lock" ]; then
+ create_lock $*
+elif [ $0 = "$basedir/vm-monitor" ]; then
+ monitor $*
+fi
