Exposed ports, env vars, volumes from the image.

This will account for settings that are provided by the hierarchy of
Dockerfiles used to construct your image, rather than only accounting
for settings provided to the module directly.

lib/ansible/modules/cloud/docker/docker.py

@@ -808,9 +808,7 @@ class DockerManager(object):
                     continue
 
             # EXPOSED PORTS
-            # Note that ports that are bound at container run are also exposed
-            # implicitly.
-            expected_exposed_ports = set()
+            expected_exposed_ports = set((image['ContainerConfig']['ExposedPorts'] or {}).keys())
             for p in (self.exposed_ports or []):
                 expected_exposed_ports.add("/".join(p))
 
@@ -824,7 +822,7 @@ class DockerManager(object):
             # VOLUMES
             # not including bind modes.
 
-            expected_volume_keys = set()
+            expected_volume_keys = set((image['ContainerConfig']['Volumes'] or {}).keys())
             if self.volumes:
                 for key, config in self.volumes.iteritems():
                     if not config and key not in self.binds:
@@ -850,13 +848,13 @@ class DockerManager(object):
             # actual_env is likely to include environment variables injected by
             # the Dockerfile.
 
-            expected_env = set()
+            expected_env = set(image['ContainerConfig']['Env'] or [])
             if self.env:
                 for name, value in self.env.iteritems():
                     expected_env.add("{}={}".format(name, value))
             actual_env = set(container['Config']['Env'] or [])
 
-            if not actual_env.issuperset(expected_env):
+            if actual_env != expected_env:
                 # Don't include the environment difference in the output.
                 self.reload_reasons.append('environment')
                 differing.append(container)