Merged trunk.

bin/nova-manage

@@ -56,11 +56,11 @@
 import gettext
 import glob
 import json
+import netaddr
 import os
 import sys
 import time
 
-import IPy
 
 # If ../nova/__init__.py exists, add ../ to Python search path, so that
 # it will override what happens to be installed in /usr/(local/)lib/python...
@@ -257,6 +257,11 @@ class RoleCommands(object):
         """adds role to user
         if project is specified, adds project specific role
         arguments: user, role [project]"""
+        if project:
+            projobj = self.manager.get_project(project)
+            if not projobj.has_member(user):
+                print "%s not a member of %s" % (user, project)
+                return
         self.manager.add_role(user, role, project)
 
     def has(self, user, role, project=None):
@@ -513,7 +518,7 @@ class FloatingIpCommands(object):
     def create(self, host, range):
         """Creates floating ips for host by range
         arguments: host ip_range"""
-        for address in IPy.IP(range):
+        for address in netaddr.IPNetwork(range):
             db.floating_ip_create(context.get_admin_context(),
                                   {'address': str(address),
                                    'host': host})
@@ -521,7 +526,7 @@ class FloatingIpCommands(object):
     def delete(self, ip_range):
         """Deletes floating ips by range
         arguments: range"""
-        for address in IPy.IP(ip_range):
+        for address in netaddr.IPNetwork(ip_range):
             db.floating_ip_destroy(context.get_admin_context(),
                                    str(address))
 
@@ -873,7 +878,7 @@ class InstanceTypeCommands(object):
         try:
             instance_types.create(name, memory, vcpus, local_gb,
                                   flavorid, swap, rxtx_quota, rxtx_cap)
-        except exception.InvalidInputException:
+        except exception.InvalidInput:
             print "Must supply valid parameters to create instance_type"
             print e
             sys.exit(1)
@@ -1071,6 +1076,70 @@ class ImageCommands(object):
         self._convert_images(machine_images)
 
 
+class AgentBuildCommands(object):
+    """Class for managing agent builds."""
+
+    def create(self, os, architecture, version, url, md5hash,
+                hypervisor='xen'):
+        """Creates a new agent build.
+        arguments: os architecture version url md5hash [hypervisor='xen']"""
+        ctxt = context.get_admin_context()
+        agent_build = db.agent_build_create(ctxt,
+                                            {'hypervisor': hypervisor,
+                                             'os': os,
+                                             'architecture': architecture,
+                                             'version': version,
+                                             'url': url,
+                                             'md5hash': md5hash})
+
+    def delete(self, os, architecture, hypervisor='xen'):
+        """Deletes an existing agent build.
+        arguments: os architecture [hypervisor='xen']"""
+        ctxt = context.get_admin_context()
+        agent_build_ref = db.agent_build_get_by_triple(ctxt,
+                                  hypervisor, os, architecture)
+        db.agent_build_destroy(ctxt, agent_build_ref['id'])
+
+    def list(self, hypervisor=None):
+        """Lists all agent builds.
+        arguments: <none>"""
+        fmt = "%-10s  %-8s  %12s  %s"
+        ctxt = context.get_admin_context()
+        by_hypervisor = {}
+        for agent_build in db.agent_build_get_all(ctxt):
+            buildlist = by_hypervisor.get(agent_build.hypervisor)
+            if not buildlist:
+                buildlist = by_hypervisor[agent_build.hypervisor] = []
+
+            buildlist.append(agent_build)
+
+        for key, buildlist in by_hypervisor.iteritems():
+            if hypervisor and key != hypervisor:
+                continue
+
+            print "Hypervisor: %s" % key
+            print fmt % ('-' * 10, '-' * 8, '-' * 12, '-' * 32)
+            for agent_build in buildlist:
+                print fmt % (agent_build.os, agent_build.architecture,
+                             agent_build.version, agent_build.md5hash)
+                print '    %s' % agent_build.url
+
+            print
+
+    def modify(self, os, architecture, version, url, md5hash,
+               hypervisor='xen'):
+        """Update an existing agent build.
+        arguments: os architecture version url md5hash [hypervisor='xen']
+        """
+        ctxt = context.get_admin_context()
+        agent_build_ref = db.agent_build_get_by_triple(ctxt,
+                                  hypervisor, os, architecture)
+        db.agent_build_update(ctxt, agent_build_ref['id'],
+                              {'version': version,
+                               'url': url,
+                               'md5hash': md5hash})
+
+
 class ConfigCommands(object):
     """Class for exposing the flags defined by flag_file(s)."""
 
@@ -1083,6 +1152,7 @@ class ConfigCommands(object):
 
 CATEGORIES = [
     ('account', AccountCommands),
+    ('agent', AgentBuildCommands),
     ('config', ConfigCommands),
     ('db', DbCommands),
     ('fixed', FixedIpCommands),

nova/tests/test_adminapi.py

@@ -0,0 +1,111 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from eventlet import greenthread
+
+from nova import context
+from nova import db
+from nova import flags
+from nova import log as logging
+from nova import rpc
+from nova import test
+from nova import utils
+from nova.auth import manager
+from nova.api.ec2 import admin
+from nova.image import fake
+
+
+FLAGS = flags.FLAGS
+LOG = logging.getLogger('nova.tests.adminapi')
+
+
+class AdminApiTestCase(test.TestCase):
+    def setUp(self):
+        super(AdminApiTestCase, self).setUp()
+        self.flags(connection_type='fake')
+
+        self.conn = rpc.Connection.instance()
+
+        # set up our cloud
+        self.api = admin.AdminController()
+
+        # set up services
+        self.compute = self.start_service('compute')
+        self.scheduter = self.start_service('scheduler')
+        self.network = self.start_service('network')
+        self.volume = self.start_service('volume')
+        self.image_service = utils.import_object(FLAGS.image_service)
+
+        self.manager = manager.AuthManager()
+        self.user = self.manager.create_user('admin', 'admin', 'admin', True)
+        self.project = self.manager.create_project('proj', 'admin', 'proj')
+        self.context = context.RequestContext(user=self.user,
+                                              project=self.project)
+        host = self.network.get_network_host(self.context.elevated())
+
+        def fake_show(meh, context, id):
+            return {'id': 1, 'properties': {'kernel_id': 1, 'ramdisk_id': 1,
+                    'type': 'machine', 'image_state': 'available'}}
+
+        self.stubs.Set(fake._FakeImageService, 'show', fake_show)
+        self.stubs.Set(fake._FakeImageService, 'show_by_name', fake_show)
+
+        # NOTE(vish): set up a manual wait so rpc.cast has a chance to finish
+        rpc_cast = rpc.cast
+
+        def finish_cast(*args, **kwargs):
+            rpc_cast(*args, **kwargs)
+            greenthread.sleep(0.2)
+
+        self.stubs.Set(rpc, 'cast', finish_cast)
+
+    def tearDown(self):
+        network_ref = db.project_get_network(self.context,
+                                             self.project.id)
+        db.network_disassociate(self.context, network_ref['id'])
+        self.manager.delete_project(self.project)
+        self.manager.delete_user(self.user)
+        super(AdminApiTestCase, self).tearDown()
+
+    def test_block_external_ips(self):
+        """Make sure provider firewall rules are created."""
+        result = self.api.block_external_addresses(self.context, '1.1.1.1/32')
+        self.api.remove_external_address_block(self.context, '1.1.1.1/32')
+        self.assertEqual('OK', result['status'])
+        self.assertEqual('Added 3 rules', result['message'])
+
+    def test_list_blocked_ips(self):
+        """Make sure we can see the external blocks that exist."""
+        self.api.block_external_addresses(self.context, '1.1.1.2/32')
+        result = self.api.describe_external_address_blocks(self.context)
+        num = len(db.provider_fw_rule_get_all(self.context))
+        self.api.remove_external_address_block(self.context, '1.1.1.2/32')
+        # we only list IP, not tcp/udp/icmp rules
+        self.assertEqual(num / 3, len(result['externalIpBlockInfo']))
+
+    def test_remove_ip_block(self):
+        """Remove ip blocks."""
+        result = self.api.block_external_addresses(self.context, '1.1.1.3/32')
+        self.assertEqual('OK', result['status'])
+        num0 = len(db.provider_fw_rule_get_all(self.context))
+        result = self.api.remove_external_address_block(self.context,
+                                                        '1.1.1.3/32')
+        self.assertEqual('OK', result['status'])
+        self.assertEqual('Deleted 3 rules', result['message'])
+        num1 = len(db.provider_fw_rule_get_all(self.context))
+        self.assert_(num1 < num0)

nova/tests/test_compute.py

@@ -281,6 +281,14 @@ class ComputeTestCase(test.TestCase):
                 "File Contents")
         self.compute.terminate_instance(self.context, instance_id)
 
+    def test_agent_update(self):
+        """Ensure instance can have its agent updated"""
+        instance_id = self._create_instance()
+        self.compute.run_instance(self.context, instance_id)
+        self.compute.agent_update(self.context, instance_id,
+                'http://127.0.0.1/agent', '00112233445566778899aabbccddeeff')
+        self.compute.terminate_instance(self.context, instance_id)
+
     def test_snapshot(self):
         """Ensure instance can be snapshotted"""
         instance_id = self._create_instance()

nova/tests/test_flat_network.py

@@ -18,7 +18,7 @@
 """
 Unit Tests for flat network code
 """
-import IPy
+import netaddr
 import os
 import unittest
 
@@ -45,8 +45,8 @@ class FlatNetworkTestCase(base.NetworkTestCase):
 
         self.context._project = self.projects[0]
         self.context.project_id = self.projects[0].id
-        pubnet = IPy.IP(flags.FLAGS.floating_range)
-        address = str(pubnet[0])
+        pubnet = netaddr.IPRange(flags.FLAGS.floating_range)
+        address = str(list(pubnet)[0])
         try:
             db.floating_ip_get_by_address(context.get_admin_context(), address)
         except exception.NotFound:

nova/tests/test_libvirt.py

@@ -799,7 +799,9 @@ class IptablesFirewallTestCase(test.TestCase):
         self.network = utils.import_object(FLAGS.network_manager)
 
         class FakeLibvirtConnection(object):
-            pass
+            def nwfilterDefineXML(*args, **kwargs):
+                """setup_basic_rules in nwfilter calls this."""
+                pass
         self.fake_libvirt_connection = FakeLibvirtConnection()
         self.fw = firewall.IptablesFirewallDriver(
                       get_connection=lambda: self.fake_libvirt_connection)
@@ -1035,7 +1037,6 @@ class IptablesFirewallTestCase(test.TestCase):
                                fakefilter.filterDefineXMLMock
         self.fw.nwfilter._conn.nwfilterLookupByName =\
                                fakefilter.nwfilterLookupByName
-
         instance_ref = self._create_instance_ref()
         inst_id = instance_ref['id']
         instance = db.instance_get(self.context, inst_id)
@@ -1057,6 +1058,70 @@ class IptablesFirewallTestCase(test.TestCase):
 
         db.instance_destroy(admin_ctxt, instance_ref['id'])
 
+    def test_provider_firewall_rules(self):
+        # setup basic instance data
+        instance_ref = self._create_instance_ref()
+        nw_info = _create_network_info(1)
+        ip = '10.11.12.13'
+        network_ref = db.project_get_network(self.context, 'fake')
+        admin_ctxt = context.get_admin_context()
+        fixed_ip = {'address': ip, 'network_id': network_ref['id']}
+        db.fixed_ip_create(admin_ctxt, fixed_ip)
+        db.fixed_ip_update(admin_ctxt, ip, {'allocated': True,
+                                            'instance_id': instance_ref['id']})
+        # FRAGILE: peeks at how the firewall names chains
+        chain_name = 'inst-%s' % instance_ref['id']
+
+        # create a firewall via setup_basic_filtering like libvirt_conn.spawn
+        # should have a chain with 0 rules
+        self.fw.setup_basic_filtering(instance_ref, network_info=nw_info)
+        self.assertTrue('provider' in self.fw.iptables.ipv4['filter'].chains)
+        rules = [rule for rule in self.fw.iptables.ipv4['filter'].rules
+                      if rule.chain == 'provider']
+        self.assertEqual(0, len(rules))
+
+        # add a rule and send the update message, check for 1 rule
+        provider_fw0 = db.provider_fw_rule_create(admin_ctxt,
+                                                  {'protocol': 'tcp',
+                                                   'cidr': '10.99.99.99/32',
+                                                   'from_port': 1,
+                                                   'to_port': 65535})
+        self.fw.refresh_provider_fw_rules()
+        rules = [rule for rule in self.fw.iptables.ipv4['filter'].rules
+                      if rule.chain == 'provider']
+        self.assertEqual(1, len(rules))
+
+        # Add another, refresh, and make sure number of rules goes to two
+        provider_fw1 = db.provider_fw_rule_create(admin_ctxt,
+                                                  {'protocol': 'udp',
+                                                   'cidr': '10.99.99.99/32',
+                                                   'from_port': 1,
+                                                   'to_port': 65535})
+        self.fw.refresh_provider_fw_rules()
+        rules = [rule for rule in self.fw.iptables.ipv4['filter'].rules
+                      if rule.chain == 'provider']
+        self.assertEqual(2, len(rules))
+
+        # create the instance filter and make sure it has a jump rule
+        self.fw.prepare_instance_filter(instance_ref, network_info=nw_info)
+        self.fw.apply_instance_filter(instance_ref)
+        inst_rules = [rule for rule in self.fw.iptables.ipv4['filter'].rules
+                           if rule.chain == chain_name]
+        jump_rules = [rule for rule in inst_rules if '-j' in rule.rule]
+        provjump_rules = []
+        # IptablesTable doesn't make rules unique internally
+        for rule in jump_rules:
+            if 'provider' in rule.rule and rule not in provjump_rules:
+                provjump_rules.append(rule)
+        self.assertEqual(1, len(provjump_rules))
+
+        # remove a rule from the db, cast to compute to refresh rule
+        db.provider_fw_rule_destroy(admin_ctxt, provider_fw1['id'])
+        self.fw.refresh_provider_fw_rules()
+        rules = [rule for rule in self.fw.iptables.ipv4['filter'].rules
+                      if rule.chain == 'provider']
+        self.assertEqual(1, len(rules))
+
 
 class NWFilterTestCase(test.TestCase):
     def setUp(self):

nova/tests/test_network.py

@@ -18,7 +18,7 @@
 """
 Unit Tests for network code
 """
-import IPy
+import netaddr
 import os
 
 from nova import test
@@ -164,3 +164,33 @@ class IptablesManagerTestCase(test.TestCase):
             self.assertTrue('-A %s -j run_tests.py-%s' \
                             % (chain, chain) in new_lines,
                             "Built-in chain %s not wrapped" % (chain,))
+
+    def test_will_empty_chain(self):
+        self.manager.ipv4['filter'].add_chain('test-chain')
+        self.manager.ipv4['filter'].add_rule('test-chain', '-j DROP')
+        old_count = len(self.manager.ipv4['filter'].rules)
+        self.manager.ipv4['filter'].empty_chain('test-chain')
+        self.assertEqual(old_count - 1, len(self.manager.ipv4['filter'].rules))
+
+    def test_will_empty_unwrapped_chain(self):
+        self.manager.ipv4['filter'].add_chain('test-chain', wrap=False)
+        self.manager.ipv4['filter'].add_rule('test-chain', '-j DROP',
+                                             wrap=False)
+        old_count = len(self.manager.ipv4['filter'].rules)
+        self.manager.ipv4['filter'].empty_chain('test-chain', wrap=False)
+        self.assertEqual(old_count - 1, len(self.manager.ipv4['filter'].rules))
+
+    def test_will_not_empty_wrapped_when_unwrapped(self):
+        self.manager.ipv4['filter'].add_chain('test-chain')
+        self.manager.ipv4['filter'].add_rule('test-chain', '-j DROP')
+        old_count = len(self.manager.ipv4['filter'].rules)
+        self.manager.ipv4['filter'].empty_chain('test-chain', wrap=False)
+        self.assertEqual(old_count, len(self.manager.ipv4['filter'].rules))
+
+    def test_will_not_empty_unwrapped_when_wrapped(self):
+        self.manager.ipv4['filter'].add_chain('test-chain', wrap=False)
+        self.manager.ipv4['filter'].add_rule('test-chain', '-j DROP',
+                                             wrap=False)
+        old_count = len(self.manager.ipv4['filter'].rules)
+        self.manager.ipv4['filter'].empty_chain('test-chain')
+        self.assertEqual(old_count, len(self.manager.ipv4['filter'].rules))

nova/tests/test_vlan_network.py

@@ -18,7 +18,7 @@
 """
 Unit Tests for vlan network code
 """
-import IPy
+import netaddr
 import os
 
 from nova import context
@@ -44,8 +44,8 @@ class VlanNetworkTestCase(base.NetworkTestCase):
         # TODO(vish): better way of adding floating ips
         self.context._project = self.projects[0]
         self.context.project_id = self.projects[0].id
-        pubnet = IPy.IP(flags.FLAGS.floating_range)
-        address = str(pubnet[0])
+        pubnet = netaddr.IPNetwork(flags.FLAGS.floating_range)
+        address = str(list(pubnet)[0])
         try:
             db.floating_ip_get_by_address(context.get_admin_context(), address)
         except exception.NotFound:

nova/tests/test_xenapi.py

@@ -37,9 +37,8 @@ from nova import exception
 from nova.virt import xenapi_conn
 from nova.virt.xenapi import fake as xenapi_fake
 from nova.virt.xenapi import volume_utils
+from nova.virt.xenapi import vmops
 from nova.virt.xenapi import vm_utils
-from nova.virt.xenapi.vmops import SimpleDH
-from nova.virt.xenapi.vmops import VMOps
 from nova.tests.db import fakes as db_fakes
 from nova.tests.xenapi import stubs
 from nova.tests.glance import stubs as glance_stubs
@@ -85,7 +84,8 @@ class XenAPIVolumeTestCase(test.TestCase):
                   'ramdisk_id': 3,
                   'instance_type_id': '3',  # m1.large
                   'mac_address': 'aa:bb:cc:dd:ee:ff',
-                  'os_type': 'linux'}
+                  'os_type': 'linux',
+                  'architecture': 'x86-64'}
 
     def _create_volume(self, size='0'):
         """Create a volume object."""
@@ -192,7 +192,7 @@ class XenAPIVMTestCase(test.TestCase):
         stubs.stubout_get_this_vm_uuid(self.stubs)
         stubs.stubout_stream_disk(self.stubs)
         stubs.stubout_is_vdi_pv(self.stubs)
-        self.stubs.Set(VMOps, 'reset_network', reset_network)
+        self.stubs.Set(vmops.VMOps, 'reset_network', reset_network)
         stubs.stub_out_vm_methods(self.stubs)
         glance_stubs.stubout_glance_client(self.stubs)
         fake_utils.stub_out_utils_execute(self.stubs)
@@ -212,7 +212,8 @@ class XenAPIVMTestCase(test.TestCase):
                 'ramdisk_id': 3,
                 'instance_type_id': '3',  # m1.large
                 'mac_address': 'aa:bb:cc:dd:ee:ff',
-                'os_type': 'linux'}
+                'os_type': 'linux',
+                'architecture': 'x86-64'}
             instance = db.instance_create(self.context, values)
             self.conn.spawn(instance)
 
@@ -370,7 +371,8 @@ class XenAPIVMTestCase(test.TestCase):
 
     def _test_spawn(self, image_ref, kernel_id, ramdisk_id,
                     instance_type_id="3", os_type="linux",
-                    instance_id=1, check_injection=False):
+                    architecture="x86-64", instance_id=1,
+                    check_injection=False):
         stubs.stubout_loopingcall_start(self.stubs)
         values = {'id': instance_id,
                   'project_id': self.project.id,
@@ -380,11 +382,14 @@ class XenAPIVMTestCase(test.TestCase):
                   'ramdisk_id': ramdisk_id,
                   'instance_type_id': instance_type_id,
                   'mac_address': 'aa:bb:cc:dd:ee:ff',
-                  'os_type': os_type}
+                  'os_type': os_type,
+                  'architecture': architecture}
         instance = db.instance_create(self.context, values)
         self.conn.spawn(instance)
         self.create_vm_record(self.conn, os_type, instance_id)
         self.check_vm_record(self.conn, check_injection)
+        self.assertTrue(instance.os_type)
+        self.assertTrue(instance.architecture)
 
     def test_spawn_not_enough_memory(self):
         FLAGS.xenapi_image_service = 'glance'
@@ -409,7 +414,7 @@ class XenAPIVMTestCase(test.TestCase):
     def test_spawn_vhd_glance_linux(self):
         FLAGS.xenapi_image_service = 'glance'
         self._test_spawn(glance_stubs.FakeGlance.IMAGE_VHD, None, None,
-                         os_type="linux")
+                         os_type="linux", architecture="x86-64")
         self.check_vm_params_for_linux()
 
     def test_spawn_vhd_glance_swapdisk(self):
@@ -438,7 +443,7 @@ class XenAPIVMTestCase(test.TestCase):
     def test_spawn_vhd_glance_windows(self):
         FLAGS.xenapi_image_service = 'glance'
         self._test_spawn(glance_stubs.FakeGlance.IMAGE_VHD, None, None,
-                         os_type="windows")
+                         os_type="windows", architecture="i386")
         self.check_vm_params_for_windows()
 
     def test_spawn_glance(self):
@@ -589,7 +594,8 @@ class XenAPIVMTestCase(test.TestCase):
             'ramdisk_id': 3,
             'instance_type_id': '3',  # m1.large
             'mac_address': 'aa:bb:cc:dd:ee:ff',
-            'os_type': 'linux'}
+            'os_type': 'linux',
+            'architecture': 'x86-64'}
         instance = db.instance_create(self.context, values)
         self.conn.spawn(instance)
         return instance
@@ -599,8 +605,8 @@ class XenAPIDiffieHellmanTestCase(test.TestCase):
     """Unit tests for Diffie-Hellman code."""
     def setUp(self):
         super(XenAPIDiffieHellmanTestCase, self).setUp()
-        self.alice = SimpleDH()
-        self.bob = SimpleDH()
+        self.alice = vmops.SimpleDH()
+        self.bob = vmops.SimpleDH()
 
     def test_shared(self):
         alice_pub = self.alice.get_public()
@@ -664,7 +670,8 @@ class XenAPIMigrateInstance(test.TestCase):
                   'local_gb': 5,
                   'instance_type_id': '3',  # m1.large
                   'mac_address': 'aa:bb:cc:dd:ee:ff',
-                  'os_type': 'linux'}
+                  'os_type': 'linux',
+                  'architecture': 'x86-64'}
 
         fake_utils.stub_out_utils_execute(self.stubs)
         stubs.stub_out_migration_methods(self.stubs)
@@ -703,6 +710,7 @@ class XenAPIDetermineDiskImageTestCase(test.TestCase):
         self.fake_instance = FakeInstance()
         self.fake_instance.id = 42
         self.fake_instance.os_type = 'linux'
+        self.fake_instance.architecture = 'x86-64'
 
     def assert_disk_type(self, disk_type):
         dt = vm_utils.VMHelper.determine_disk_image_type(
@@ -747,6 +755,28 @@ class XenAPIDetermineDiskImageTestCase(test.TestCase):
         self.assert_disk_type(vm_utils.ImageType.DISK_VHD)
 
 
+class CompareVersionTestCase(test.TestCase):
+    def test_less_than(self):
+        """Test that cmp_version compares a as less than b"""
+        self.assertTrue(vmops.cmp_version('1.2.3.4', '1.2.3.5') < 0)
+
+    def test_greater_than(self):
+        """Test that cmp_version compares a as greater than b"""
+        self.assertTrue(vmops.cmp_version('1.2.3.5', '1.2.3.4') > 0)
+
+    def test_equal(self):
+        """Test that cmp_version compares a as equal to b"""
+        self.assertTrue(vmops.cmp_version('1.2.3.4', '1.2.3.4') == 0)
+
+    def test_non_lexical(self):
+        """Test that cmp_version compares non-lexically"""
+        self.assertTrue(vmops.cmp_version('1.2.3.10', '1.2.3.4') > 0)
+
+    def test_length(self):
+        """Test that cmp_version compares by length as last resort"""
+        self.assertTrue(vmops.cmp_version('1.2.3', '1.2.3.4') < 0)
+
+
 class FakeXenApi(object):
     """Fake XenApi for testing HostState."""