--- xen/xm/create.py	2008-04-14 23:48:49.000000000 +0200
+++ xen/xm/create.py	2008-04-27 02:42:44.000000000 +0200
@@ -28,6 +28,7 @@
 import xmlrpclib
 
 from xen.xend import sxp
+from xen.xend import XendOptions
 from xen.xend import PrettyPrint as SXPPrettyPrint
 from xen.xend import osdep
 import xen.xend.XendClient
@@ -1045,7 +1046,6 @@
             d[k] = v
     return d
 
-
 def make_domain(opts, config):
     """Create, build and start a domain.
 
@@ -1055,6 +1055,51 @@
     @rtype:  int
     """
 
+    # This would be the right place to insert cluster awareness
+    # 
+    # So let's do it[tm]
+
+    # FIXME
+    # Most probably there is a much nicer way to get the name
+    # of the domain to be started. But hey, I'm new to python
+    # and got this idea from a friend.
+    def get_name_from_config (c_list):
+        for item in c_list:
+            try:
+                if item[0] == 'name':
+                    return item[1]
+            except:
+                pass
+        return None
+
+    # Should we do locking?
+    if XendOptions.instance().get_cluster_locking() == 'yes':
+        opts.info ("Cluster locking check activated.")
+    
+        cluster_locking_dir = XendOptions.instance().get_cluster_locking_dir()
+        domain_name = get_name_from_config (config)
+
+        if not os.path.isdir (cluster_locking_dir):
+            err ("Cluster locking dir \"%s\" does not exist!\n" % cluster_locking_dir)
+
+        # Where to look for/create the lockfile
+        lockfile_path = cluster_locking_dir + '/' + domain_name + '.lock'
+
+        # If there already exists a lockfile, try to get the name 
+	# of the Dom0 hosting the domain
+	if os.path.isfile (lockfile_path):
+	    lockfile = open (lockfile_path, 'r')
+	    other_node = lockfile.readline()
+	    lockfile.close ()
+
+            err ("Sorry, domain \"%s\" seems to be already running on this cluster on node \"%s\".\n" % (domain_name, other_node))
+
+        # OK, no lockfile found, create it and proceed
+        lockfile = open (lockfile_path, 'w')
+	lockfile.write (str (socket.gethostname ()))
+	lockfile.close ()
+
+    # Normal startup
     try:
         dominfo = server.xend.domain.create(config)
     except xmlrpclib.Fault, ex: