only claim vmExec tasks if the requested VM is available on the current host

vm/kojivmd

@@ -781,6 +781,22 @@ class VMTaskManager(TaskManager):
         """See if we have enough space to accept another job"""
         return self.checkDisk() and self.checkMem()
 
+    def takeTask(self, task):
+        """
+        Verify that this builder can handle the task before claiming it.
+        """
+        if task['method'] == 'vmExec':
+            task_info = self.session.getTaskInfo(task['id'], request=True)
+            vm_name = task_info['request'][0]
+            try:
+                vm = self.libvirt_conn.lookupByName(vm_name)
+            except libvirt.libvirtError:
+                # if this builder does not have the requested VM,
+                # we can't handle the task
+                self.logger.debug('VM %s not available, ignoring task %i', vm_name, task['id'])
+                return False
+        return super(VMTaskManager, self).takeTask(task)
+
     def cleanupVM(self, vm_name):
         """
         Cleanup a single VM with the given name.