diff --git a/_tests/Makefile b/_tests/Makefile
--- a/_tests/Makefile
+++ b/_tests/Makefile
@@ -1,3 +1,3 @@
 test:
 	python -m unittest discover modules
-
+	python -m unittest discover pillar
diff --git a/_tests/pillar/__init__.py b/_tests/pillar/__init__.py
new file mode 100644
diff --git a/_tests/pillar/paas/__init__.py b/_tests/pillar/paas/__init__.py
new file mode 100644
diff --git a/_tests/pillar/paas/test_docker.py b/_tests/pillar/paas/test_docker.py
new file mode 100644
--- /dev/null
+++ b/_tests/pillar/paas/test_docker.py
@@ -0,0 +1,25 @@
+import unittest
+import yaml
+
+
+PILLAR_FILE = '../pillar/paas/docker.sls'
+
+
+class Testinstance(unittest.TestCase):
+
+    def setUp(self):
+        with open(PILLAR_FILE, 'r') as fd:
+            self.pillar = yaml.load(fd)
+
+    # nginx needs a host/app_port pair to spawn a configuration
+    def test_host_is_paired_with_app_port_option(self):
+        for node, services in self.pillar['docker_containers'].items():
+            for service, containers in services.items():
+                for instance, container in containers.items():
+                    if 'host' not in container:
+                        continue
+
+                    entry = ':'.join(['docker_containers', node,
+                                      service, instance])
+                    self.assertIn('app_port', container,
+                                  entry + ": app_port missing")
diff --git a/pillar/paas/docker.sls b/pillar/paas/docker.sls
--- a/pillar/paas/docker.sls
+++ b/pillar/paas/docker.sls
@@ -348,7 +348,7 @@
     # declared above.
     exim:
       sentry_smtp:
-        host: mx.sentry.nasqueron.org
+        mailname: mx.sentry.nasqueron.org
 
     sentry:
       sentry_web_1:
diff --git a/roles/paas-docker/containers/exim.sls b/roles/paas-docker/containers/exim.sls
--- a/roles/paas-docker/containers/exim.sls
+++ b/roles/paas-docker/containers/exim.sls
@@ -28,7 +28,7 @@
 
 /srv/exim/{{ instance }}/mailname:
   file.managed:
-    - contents: {{ container['host'] }}
+    - contents: {{ container['mailname'] }}
 
 {% if has_selinux %}
 
@@ -57,7 +57,7 @@
 
 {% if 'host' in container %}
     - binds: /srv/exim/{{ instance }}/mailname:/etc/mailname:ro
-    - hostname: container['host']
+    - hostname: container['mailname']
 {% endif %}
 
 {% if 'network' in container %}