Merge pull request #343 from cmccoy/no-migration

Enable optional migration on GCE. No change to default.

perfkitbenchmarker/gcp/gce_virtual_machine.py

@@ -45,6 +45,8 @@
                      '(see https://cloud.google.com/compute/docs/local-ssd).')
 flags.DEFINE_string('gcloud_scopes', None, 'If set, space-separated list of '
                     'scopes to apply to every created machine')
+flags.DEFINE_boolean('gce_migrate_on_maintenance', False, 'If true, allow VM '
+                     'migration on GCE host maintenance.')
 
 FLAGS = flags.FLAGS
 
@@ -117,14 +119,16 @@ def _Create(self):
                     'mode=rw',
                     '--machine-type', self.machine_type,
                     '--tags=perfkitbenchmarker',
-                    '--maintenance-policy', 'TERMINATE',
                     '--no-restart-on-failure',
                     '--metadata-from-file',
                     'sshKeys=%s' % tf.name,
                     '--metadata',
                     'owner=%s' % FLAGS.owner]
       for key, value in self.boot_metadata.iteritems():
         create_cmd.append('%s=%s' % (key, value))
+      if not FLAGS.gce_migrate_on_maintenance:
+        create_cmd.extend(['--maintenance-policy', 'TERMINATE'])
+
       ssd_interface_option = NVME if NVME in self.image else SCSI
       for _ in range(self.max_local_disks):
         create_cmd.append('--local-ssd')