diff --git a/etc/heat/heat.conf.sample b/etc/heat/heat.conf.sample
index 212e071179..34e3d22cd7 100644
--- a/etc/heat/heat.conf.sample
+++ b/etc/heat/heat.conf.sample
@@ -14,7 +14,11 @@
 # Options defined in heat.common.config
 #
 
-# The default user for new instances. (string value)
+# The default user for new instances. This option is
+# deprecated and will be removed in the Juno release. If it's
+# empty, Heat will use the default user set up with your cloud
+# image (for OS::Nova::Server) or 'ec2-user' (for
+# AWS::EC2::Instance). (string value)
 #instance_user=ec2-user
 
 # Driver to use for controlling instances. (string value)
diff --git a/heat/cloudinit/boothook.sh b/heat/cloudinit/boothook.sh
index 0b8b219f8d..a4b71329ad 100755
--- a/heat/cloudinit/boothook.sh
+++ b/heat/cloudinit/boothook.sh
@@ -1,11 +1,14 @@
 #!/bin/bash
 
-# FIXME(shadower) The `useradd` and `sudoers` lines are a workaround for
-# cloud-init 0.6.3 present in Ubuntu 12.04 LTS:
+# FIXME(shadower) this is a workaround for cloud-init 0.6.3 present in Ubuntu
+# 12.04 LTS:
 # https://bugs.launchpad.net/heat/+bug/1257410
-# Once we drop support for it, we can safely remove them.
-useradd -m @INSTANCE_USER@
-echo -e '@INSTANCE_USER@\tALL=(ALL)\tNOPASSWD: ALL' >> /etc/sudoers
+#
+# The old cloud-init doesn't create the users directly so the commands to do
+# this are injected though nova_utils.py.
+#
+# Once we drop support for 0.6.3, we can safely remove this.
+${add_custom_user}
 
 # in case heat-cfntools has been installed from package but no symlinks
 # are yet in /opt/aws/bin/
diff --git a/heat/cloudinit/config b/heat/cloudinit/config
index 555900881c..d9471a0bd8 100644
--- a/heat/cloudinit/config
+++ b/heat/cloudinit/config
@@ -1,8 +1,4 @@
-# Set the SSH key provided by Nova to this user.
-# On cloud-init 0.7.x (anything except Ubuntu 12.04 LTS which ships 0.6.3) this
-# also creates the user and sets up passwordless sudo if the user isn't present
-# already.
-user: @INSTANCE_USER@
+${add_custom_user}
 
 # Capture all subprocess output into a logfile
 # Useful for troubleshooting cloud-init issues
diff --git a/heat/common/config.py b/heat/common/config.py
index d1065c781a..922014faeb 100644
--- a/heat/common/config.py
+++ b/heat/common/config.py
@@ -28,6 +28,8 @@ from heat.common import wsgi
 from heat.openstack.common import log as logging
 from heat.openstack.common import rpc
 
+logger = logging.getLogger(__name__)
+
 paste_deploy_group = cfg.OptGroup('paste_deploy')
 paste_deploy_opts = [
     cfg.StrOpt('flavor',
@@ -80,7 +82,11 @@ service_opts = [
 engine_opts = [
     cfg.StrOpt('instance_user',
                default='ec2-user',
-               help='The default user for new instances.'),
+               help="The default user for new instances. This option "
+                    "is deprecated and will be removed in the Juno release. "
+                    "If it's empty, Heat will use the default user set up "
+                    "with your cloud image (for OS::Nova::Server) or "
+                    "'ec2-user' (for AWS::EC2::Instance)."),
     cfg.StrOpt('instance_driver',
                default='heat.engine.nova',
                help='Driver to use for controlling instances.'),
@@ -213,6 +219,10 @@ allowed_rpc_exception_modules.append('heat.common.exception')
 cfg.CONF.set_default(name='allowed_rpc_exception_modules',
                      default=allowed_rpc_exception_modules)
 
+if cfg.CONF.instance_user:
+    logger.warn(_('The "instance_user" option in heat.conf is deprecated and '
+                  'will be removed in the Juno release.'))
+
 
 def _get_deployment_flavor():
     """
diff --git a/heat/engine/resources/instance.py b/heat/engine/resources/instance.py
index 48f29dfd6d..3020dd88b0 100644
--- a/heat/engine/resources/instance.py
+++ b/heat/engine/resources/instance.py
@@ -12,6 +12,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo.config import cfg
+
+cfg.CONF.import_opt('instance_user', 'heat.common.config')
+
 from heat.common import exception
 from heat.engine import clients
 from heat.engine import constraints
@@ -430,6 +434,14 @@ class Instance(resource.Resource):
                                 subnet_id=self.properties[self.SUBNET_ID])
         server = None
 
+        # FIXME(shadower): the instance_user config option is deprecated. Once
+        # it's gone, we should always use ec2-user for compatibility with
+        # CloudFormation.
+        if cfg.CONF.instance_user:
+            instance_user = cfg.CONF.instance_user
+        else:
+            instance_user = 'ec2-user'
+
         try:
             server = self.nova().servers.create(
                 name=self.physical_resource_name(),
@@ -437,7 +449,8 @@ class Instance(resource.Resource):
                 flavor=flavor_id,
                 key_name=self.properties[self.KEY_NAME],
                 security_groups=security_groups,
-                userdata=nova_utils.build_userdata(self, userdata),
+                userdata=nova_utils.build_userdata(self, userdata,
+                                                   instance_user),
                 meta=self._get_nova_metadata(self.properties),
                 scheduler_hints=scheduler_hints,
                 nics=nics,
diff --git a/heat/engine/resources/nova_utils.py b/heat/engine/resources/nova_utils.py
index 32070d7cbf..d011d0db2c 100644
--- a/heat/engine/resources/nova_utils.py
+++ b/heat/engine/resources/nova_utils.py
@@ -19,6 +19,7 @@ from email.mime.text import MIMEText
 import json
 import os
 import pkgutil
+import string
 
 from oslo.config import cfg
 import six
@@ -187,16 +188,33 @@ def build_userdata(resource, userdata=None, instance_user=None,
         return msg
 
     def read_cloudinit_file(fn):
-        data = pkgutil.get_data('heat', 'cloudinit/%s' % fn)
-        data = data.replace('@INSTANCE_USER@',
-                            instance_user or cfg.CONF.instance_user)
-        return data
+        return pkgutil.get_data('heat', 'cloudinit/%s' % fn)
 
-    attachments = [(read_cloudinit_file('config'), 'cloud-config'),
-                   (read_cloudinit_file('boothook.sh'), 'boothook.sh',
-                    'cloud-boothook')]
-    attachments.append((read_cloudinit_file('part_handler.py'),
-                       'part-handler.py'))
+    if instance_user:
+        config_custom_user = 'user: %s' % instance_user
+        # FIXME(shadower): compatibility workaround for cloud-init 0.6.3. We
+        # can drop this once we stop supporting 0.6.3 (which ships with Ubuntu
+        # 12.04 LTS).
+        #
+        # See bug https://bugs.launchpad.net/heat/+bug/1257410
+        boothook_custom_user = r"""useradd -m %s
+echo -e '%s\tALL=(ALL)\tNOPASSWD: ALL' >> /etc/sudoers
+""" % (instance_user, instance_user)
+    else:
+        config_custom_user = ''
+        boothook_custom_user = ''
+
+    cloudinit_config = string.Template(
+        read_cloudinit_file('config')).safe_substitute(
+            add_custom_user=config_custom_user)
+    cloudinit_boothook = string.Template(
+        read_cloudinit_file('boothook.sh')).safe_substitute(
+            add_custom_user=boothook_custom_user)
+
+    attachments = [(cloudinit_config, 'cloud-config'),
+                   (cloudinit_boothook, 'boothook.sh', 'cloud-boothook'),
+                   (read_cloudinit_file('part_handler.py'),
+                    'part-handler.py')]
 
     if is_cfntools:
         attachments.append((userdata, 'cfn-userdata', 'x-cfninitdata'))
diff --git a/heat/engine/resources/server.py b/heat/engine/resources/server.py
index a6e61b58ef..82e90c9c7a 100644
--- a/heat/engine/resources/server.py
+++ b/heat/engine/resources/server.py
@@ -171,8 +171,12 @@ class Server(stack_user.StackUser):
         ),
         ADMIN_USER: properties.Schema(
             properties.Schema.STRING,
-            _('Name of the administrative user to use on the server.'),
-            default=cfg.CONF.instance_user
+            _('Name of the administrative user to use on the server. '
+              'This property will be removed from Juno in favor of the '
+              'default cloud-init user set up for each image (e.g. "ubuntu" '
+              'for Ubuntu 12.04+, "fedora" for Fedora 19+ and "cloud-user" '
+              'for CentOS/RHEL 6.5).'),
+            support_status=support.SupportStatus(status=support.DEPRECATED)
         ),
         AVAILABILITY_ZONE: properties.Schema(
             properties.Schema.STRING,
@@ -470,10 +474,17 @@ class Server(stack_user.StackUser):
         if self.user_data_software_config():
             self._create_transport_credentials()
 
+        if self.properties[self.ADMIN_USER]:
+            instance_user = self.properties[self.ADMIN_USER]
+        elif cfg.CONF.instance_user:
+            instance_user = cfg.CONF.instance_user
+        else:
+            instance_user = None
+
         userdata = nova_utils.build_userdata(
             self,
             ud_content,
-            instance_user=self.properties[self.ADMIN_USER],
+            instance_user=instance_user,
             user_data_format=user_data_format)
 
         flavor = self.properties[self.FLAVOR]
diff --git a/heat/tests/test_engine_service.py b/heat/tests/test_engine_service.py
index 70a784898d..f31d4bc81c 100644
--- a/heat/tests/test_engine_service.py
+++ b/heat/tests/test_engine_service.py
@@ -195,11 +195,13 @@ def setup_mocks(mocks, stack):
 
     instance = stack['WebServer']
     user_data = instance.properties['UserData']
-    server_userdata = nova_utils.build_userdata(instance, user_data)
+    server_userdata = nova_utils.build_userdata(instance, user_data,
+                                                'ec2-user')
     mocks.StubOutWithMock(nova_utils, 'build_userdata')
     nova_utils.build_userdata(
         instance,
-        instance.t['Properties']['UserData']).AndReturn(server_userdata)
+        instance.t['Properties']['UserData'],
+        'ec2-user').AndReturn(server_userdata)
 
     mocks.StubOutWithMock(fc.servers, 'create')
     fc.servers.create(image=744, flavor=3, key_name='test',
diff --git a/heat/tests/test_instance.py b/heat/tests/test_instance.py
index aa4db56525..3923378c9e 100644
--- a/heat/tests/test_instance.py
+++ b/heat/tests/test_instance.py
@@ -93,16 +93,6 @@ class InstancesTest(HeatTestCase):
         instance.t = instance.stack.resolve_runtime_data(instance.t)
 
         if stub_create:
-            # need to resolve the template functions
-            server_userdata = nova_utils.build_userdata(
-                instance,
-                instance.t['Properties']['UserData'])
-            self.m.StubOutWithMock(nova_utils, 'build_userdata')
-            nova_utils.build_userdata(
-                instance,
-                instance.t['Properties']['UserData']).AndReturn(
-                    server_userdata)
-
             self.m.StubOutWithMock(self.fc.servers, 'create')
             self.fc.servers.create(
                 image=1, flavor=1, key_name='test',
@@ -111,7 +101,7 @@ class InstancesTest(HeatTestCase):
                     instance.name,
                     limit=instance.physical_resource_name_limit),
                 security_groups=None,
-                userdata=server_userdata, scheduler_hints=None,
+                userdata=mox.IgnoreArg(), scheduler_hints=None,
                 meta=None, nics=None, availability_zone=None).AndReturn(
                     return_server)
 
@@ -855,3 +845,50 @@ class InstancesTest(HeatTestCase):
                                               'wo_ipaddr')
 
         self.assertEqual('0.0.0.0', instance.FnGetAtt('PrivateIp'))
+
+    def test_default_instance_user(self):
+        """The default value for instance_user in heat.conf is ec2-user."""
+        return_server = self.fc.servers.list()[1]
+        instance = self._setup_test_instance(return_server, 'default_user')
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(instance, 'wordpress', 'ec2-user')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(instance.create)()
+        self.m.VerifyAll()
+
+    def test_custom_instance_user(self):
+        """Test instance_user in heat.conf being set to a custom value.
+
+        Launching the instance should call build_userdata with the custom user
+        name.
+
+        This option is deprecated and will be removed in Juno.
+        """
+        return_server = self.fc.servers.list()[1]
+        instance = self._setup_test_instance(return_server, 'custom_user')
+        self.m.StubOutWithMock(instances.cfg.CONF, 'instance_user')
+        instances.cfg.CONF.instance_user = 'custom_user'
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(instance, 'wordpress', 'custom_user')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(instance.create)()
+        self.m.VerifyAll()
+
+    def test_empty_instance_user(self):
+        """Test instance_user in heat.conf being empty.
+
+        Launching the instance should call build_userdata with
+        "ec2-user".
+
+        This behaviour is compatible with CloudFormation and will be
+        the default in Juno once the instance_user option gets removed.
+        """
+        return_server = self.fc.servers.list()[1]
+        instance = self._setup_test_instance(return_server, 'empty_user')
+        self.m.StubOutWithMock(instances.cfg.CONF, 'instance_user')
+        instances.cfg.CONF.instance_user = ''
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(instance, 'wordpress', 'ec2-user')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(instance.create)()
+        self.m.VerifyAll()
diff --git a/heat/tests/test_instance_network.py b/heat/tests/test_instance_network.py
index dfdd62b3e1..5b16fa4a97 100644
--- a/heat/tests/test_instance_network.py
+++ b/heat/tests/test_instance_network.py
@@ -178,11 +178,13 @@ class instancesTest(HeatTestCase):
         # need to resolve the template functions
         server_userdata = nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData'])
+            instance.t['Properties']['UserData'],
+            'ec2-user')
         self.m.StubOutWithMock(nova_utils, 'build_userdata')
         nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData']).AndReturn(server_userdata)
+            instance.t['Properties']['UserData'],
+            'ec2-user').AndReturn(server_userdata)
 
         self.m.StubOutWithMock(self.fc.servers, 'create')
         self.fc.servers.create(
@@ -232,11 +234,13 @@ class instancesTest(HeatTestCase):
         # need to resolve the template functions
         server_userdata = nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData'])
+            instance.t['Properties']['UserData'],
+            'ec2-user')
         self.m.StubOutWithMock(nova_utils, 'build_userdata')
         nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData']).AndReturn(server_userdata)
+            instance.t['Properties']['UserData'],
+            'ec2-user').AndReturn(server_userdata)
 
         self.m.StubOutWithMock(self.fc.servers, 'create')
         self.fc.servers.create(
diff --git a/heat/tests/test_nokey.py b/heat/tests/test_nokey.py
index 4a8aa3da1b..36d970e87e 100644
--- a/heat/tests/test_nokey.py
+++ b/heat/tests/test_nokey.py
@@ -68,11 +68,13 @@ class nokeyTest(HeatTestCase):
         # need to resolve the template functions
         server_userdata = nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData'])
+            instance.t['Properties']['UserData'],
+            'ec2-user')
         self.m.StubOutWithMock(nova_utils, 'build_userdata')
         nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData']).AndReturn(server_userdata)
+            instance.t['Properties']['UserData'],
+            'ec2-user').AndReturn(server_userdata)
 
         self.m.StubOutWithMock(self.fc.servers, 'create')
         self.fc.servers.create(
diff --git a/heat/tests/test_nova_utils.py b/heat/tests/test_nova_utils.py
index babc4da16f..3e382ba917 100644
--- a/heat/tests/test_nova_utils.py
+++ b/heat/tests/test_nova_utils.py
@@ -161,17 +161,6 @@ class NovaUtilsRefreshServerTests(HeatTestCase):
 
 class NovaUtilsUserdataTests(HeatTestCase):
 
-    scenarios = [
-        ('no_conf_no_prop', dict(
-            conf_user='ec2-user', instance_user=None, expect='ec2-user')),
-        ('no_conf_prop', dict(
-            conf_user='ec2-user', instance_user='fruity', expect='fruity')),
-        ('conf_no_prop', dict(
-            conf_user='nutty', instance_user=None, expect='nutty')),
-        ('conf_prop', dict(
-            conf_user='nutty', instance_user='fruity', expect='fruity')),
-    ]
-
     def setUp(self):
         super(NovaUtilsUserdataTests, self).setUp()
         self.nova_client = self.m.CreateMockAnything()
@@ -182,14 +171,12 @@ class NovaUtilsUserdataTests(HeatTestCase):
         resource.metadata = {}
         self.m.StubOutWithMock(nova_utils.cfg, 'CONF')
         cnf = nova_utils.cfg.CONF
-        cnf.instance_user = self.conf_user
         cnf.heat_metadata_server_url = 'http://server.test:123'
         cnf.heat_watch_server_url = 'http://server.test:345'
         cnf.instance_connection_is_secure = False
         cnf.instance_connection_https_validate_certificates = False
         self.m.ReplayAll()
-        data = nova_utils.build_userdata(resource,
-                                         instance_user=self.instance_user)
+        data = nova_utils.build_userdata(resource)
         self.assertIn("Content-Type: text/cloud-config;", data)
         self.assertIn("Content-Type: text/cloud-boothook;", data)
         self.assertIn("Content-Type: text/part-handler;", data)
@@ -198,7 +185,38 @@ class NovaUtilsUserdataTests(HeatTestCase):
         self.assertIn("http://server.test:345", data)
         self.assertIn("http://server.test:123", data)
         self.assertIn("[Boto]", data)
-        self.assertIn(self.expect, data)
+        self.m.VerifyAll()
+
+    def test_build_userdata_without_instance_user(self):
+        """Don't add a custom instance user when not requested."""
+        resource = self.m.CreateMockAnything()
+        resource.metadata = {}
+        self.m.StubOutWithMock(nova_utils.cfg, 'CONF')
+        cnf = nova_utils.cfg.CONF
+        cnf.instance_user = 'config_instance_user'
+        cnf.heat_metadata_server_url = 'http://server.test:123'
+        cnf.heat_watch_server_url = 'http://server.test:345'
+        self.m.ReplayAll()
+        data = nova_utils.build_userdata(resource, instance_user=None)
+        self.assertNotIn('user: ', data)
+        self.assertNotIn('useradd', data)
+        self.assertNotIn('config_instance_user', data)
+        self.m.VerifyAll()
+
+    def test_build_userdata_with_instance_user(self):
+        """Add the custom instance user when requested."""
+        resource = self.m.CreateMockAnything()
+        resource.metadata = {}
+        self.m.StubOutWithMock(nova_utils.cfg, 'CONF')
+        cnf = nova_utils.cfg.CONF
+        cnf.instance_user = 'config_instance_user'
+        cnf.heat_metadata_server_url = 'http://server.test:123'
+        cnf.heat_watch_server_url = 'http://server.test:345'
+        self.m.ReplayAll()
+        data = nova_utils.build_userdata(resource,
+                                         instance_user="custominstanceuser")
+        self.assertNotIn('config_instance_user', data)
+        self.assertIn("custominstanceuser", data)
         self.m.VerifyAll()
 
 
diff --git a/heat/tests/test_server.py b/heat/tests/test_server.py
index 6a80f700bb..0d4d18890b 100644
--- a/heat/tests/test_server.py
+++ b/heat/tests/test_server.py
@@ -1858,7 +1858,100 @@ class ServersTest(HeatTestCase):
         self.m.ReplayAll()
 
         self.assertEqual(server._resolve_attribute("accessIPv4"), '')
+        self.m.VerifyAll()
 
+    def test_default_instance_user(self):
+        """The default value for instance_user in heat.conf is ec2-user."""
+        return_server = self.fc.servers.list()[1]
+        server = self._setup_test_server(return_server, 'default_user')
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(server,
+                                  'wordpress',
+                                  instance_user='ec2-user',
+                                  user_data_format='HEAT_CFNTOOLS')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(server.create)()
+        self.m.VerifyAll()
+
+    def test_admin_user_property(self):
+        """Test the admin_user property on the server overrides instance_user.
+
+        Launching the instance should call build_userdata with the
+        custom user name. This property is deprecated and will be
+        removed in Juno.
+        """
+        return_server = self.fc.servers.list()[1]
+        stack_name = 'stack_with_custom_admin_user_server'
+        (t, stack) = self._setup_test_stack(stack_name)
+
+        t['Resources']['WebServer']['Properties']['admin_user'] = 'custom_user'
+        server = servers.Server('create_metadata_test_server',
+                                t['Resources']['WebServer'], stack)
+        server.t = server.stack.resolve_runtime_data(server.t)
+        self.m.StubOutWithMock(self.fc.servers, 'create')
+        self.fc.servers.create(
+            image=mox.IgnoreArg(), flavor=mox.IgnoreArg(), key_name='test',
+            name=mox.IgnoreArg(), security_groups=[],
+            userdata=mox.IgnoreArg(), scheduler_hints=None,
+            meta=mox.IgnoreArg(), nics=None, availability_zone=None,
+            block_device_mapping=None, config_drive=None,
+            disk_config=None, reservation_id=None, files={},
+            admin_pass=None).AndReturn(return_server)
+        self.m.StubOutWithMock(server, 'nova')
+        server.nova().MultipleTimes().AndReturn(self.fc)
+        self.m.StubOutWithMock(clients.OpenStackClients, 'nova')
+        clients.OpenStackClients.nova().MultipleTimes().AndReturn(self.fc)
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(server,
+                                  'wordpress',
+                                  instance_user='custom_user',
+                                  user_data_format='HEAT_CFNTOOLS')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(server.create)()
+        self.m.VerifyAll()
+
+    def test_custom_instance_user(self):
+        """Test instance_user in heat.conf being set to a custom value.
+
+        Launching the instance should call build_userdata with the
+        custom user name.
+
+        This option is deprecated and will be removed in Juno.
+        """
+        return_server = self.fc.servers.list()[1]
+        server = self._setup_test_server(return_server, 'custom_user')
+        self.m.StubOutWithMock(servers.cfg.CONF, 'instance_user')
+        servers.cfg.CONF.instance_user = 'custom_user'
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(server,
+                                  'wordpress',
+                                  instance_user='custom_user',
+                                  user_data_format='HEAT_CFNTOOLS')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(server.create)()
+        self.m.VerifyAll()
+
+    def test_empty_instance_user(self):
+        """Test instance_user in heat.conf being empty.
+
+        Launching the instance should not pass any user to
+        build_userdata. The default cloud-init user set up for the image
+        will be used instead.
+
+        This will the default behaviour in Juno once we remove the
+        instance_user option.
+        """
+        return_server = self.fc.servers.list()[1]
+        server = self._setup_test_server(return_server, 'custom_user')
+        self.m.StubOutWithMock(servers.cfg.CONF, 'instance_user')
+        servers.cfg.CONF.instance_user = ''
+        self.m.StubOutWithMock(nova_utils, 'build_userdata')
+        nova_utils.build_userdata(server,
+                                  'wordpress',
+                                  instance_user=None,
+                                  user_data_format='HEAT_CFNTOOLS')
+        self.m.ReplayAll()
+        scheduler.TaskRunner(server.create)()
         self.m.VerifyAll()
 
 
diff --git a/heat/tests/test_server_tags.py b/heat/tests/test_server_tags.py
index e0f10f8893..00f61a1dac 100644
--- a/heat/tests/test_server_tags.py
+++ b/heat/tests/test_server_tags.py
@@ -151,11 +151,13 @@ class ServerTagsTest(HeatTestCase):
         # need to resolve the template functions
         server_userdata = nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData'])
+            instance.t['Properties']['UserData'],
+            'ec2-user')
         self.m.StubOutWithMock(nova_utils, 'build_userdata')
         nova_utils.build_userdata(
             instance,
-            instance.t['Properties']['UserData']).AndReturn(server_userdata)
+            instance.t['Properties']['UserData'],
+            'ec2-user').AndReturn(server_userdata)
 
         self.m.StubOutWithMock(self.fc.servers, 'create')
         self.fc.servers.create(