Added support for --read-only Docker containers

Adds support for mounting the container's root filesystem as read only.

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

@@ -270,6 +270,12 @@ options:
     default: DockerHub
     aliases: []
     version_added: "1.8"
+  read_only:
+    description:
+      - Mount the container's root filesystem as read only
+    default: false
+    aliases: []
+    version_added: "1.9"
   restart_policy:
     description:
       - Container restart policy.
@@ -791,6 +797,7 @@ class DockerManager(object):
             'privileged': self.module.params.get('privileged'),
             'links': self.links,
             'network_mode': self.module.params.get('net'),
+            'read_only': self.module.params.get('read_only'),
         }
 
         optionals = {}
@@ -1651,6 +1658,7 @@ def main():
             cpu_set         = dict(default=None),
             cap_add         = dict(default=None, type='list'),
             cap_drop        = dict(default=None, type='list'),
+            read_only       = dict(default=False, type='bool'),
         ),
         required_together = (
             ['tls_client_cert', 'tls_client_key'],