diff --git a/lib/ansible/modules/system/authorized_key.py b/lib/ansible/modules/system/authorized_key.py
index d0f378b919a..9bf8e45b285 100644
--- a/lib/ansible/modules/system/authorized_key.py
+++ b/lib/ansible/modules/system/authorized_key.py
@@ -79,6 +79,14 @@ options:
     default: "yes"
     choices: ["yes", "no"]
     version_added: "2.1"
+  comment:
+    description:
+      - Change the comment on the public key. Rewriting the comment is useful in
+        cases such as fetching it from GitHub or GitLab.
+      - If no comment is specified, the existing comment will be kept.
+    required: false
+    default: None
+    version_added: "2.4"
 author: "Ansible Core Team"
 '''
 
@@ -220,6 +228,7 @@ from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.pycompat24 import get_exception
 from ansible.module_utils.urls import fetch_url
 
+
 class keydict(dict):
 
     """ a dictionary that maintains the order of keys as they are added
@@ -247,8 +256,8 @@ class keydict(dict):
     # http://stackoverflow.com/questions/2328235/pythonextend-the-dict-class
 
     def __init__(self, *args, **kw):
-        super(keydict,self).__init__(*args, **kw)
-        self.itemlist = list(super(keydict,self).keys())
+        super(keydict, self).__init__(*args, **kw)
+        self.itemlist = list(super(keydict, self).keys())
 
     def __setitem__(self, key, value):
         self.itemlist.append(key)
@@ -309,12 +318,12 @@ def keyfile(module, user, write=False, path=None, manage_dir=True):
             module.fail_json(msg="Either user must exist or you must provide full path to key file in check mode")
         module.fail_json(msg="Failed to lookup user %s: %s" % (user, str(e)))
     if path is None:
-        homedir    = user_entry.pw_dir
-        sshdir     = os.path.join(homedir, ".ssh")
-        keysfile   = os.path.join(sshdir, "authorized_keys")
+        homedir = user_entry.pw_dir
+        sshdir = os.path.join(homedir, ".ssh")
+        keysfile = os.path.join(sshdir, "authorized_keys")
     else:
-        sshdir     = os.path.dirname(path)
-        keysfile   = path
+        sshdir = os.path.dirname(path)
+        keysfile = path
 
     if not write:
         return keysfile
@@ -335,7 +344,7 @@ def keyfile(module, user, write=False, path=None, manage_dir=True):
         if not os.path.exists(basedir):
             os.makedirs(basedir)
         try:
-            f = open(keysfile, "w") #touches file so we can set ownership and perms
+            f = open(keysfile, "w")  # touches file so we can set ownership and perms
         finally:
             f.close()
         if module.selinux_enabled():
@@ -349,12 +358,13 @@ def keyfile(module, user, write=False, path=None, manage_dir=True):
 
     return keysfile
 
+
 def parseoptions(module, options):
     '''
     reads a string containing ssh-key options
     and returns a dictionary of those options
     '''
-    options_dict = keydict() #ordered dict
+    options_dict = keydict()  # ordered dict
     if options:
         # the following regex will split on commas while
         # ignoring those commas that fall within quotes
@@ -369,6 +379,7 @@ def parseoptions(module, options):
 
     return options_dict
 
+
 def parsekey(module, raw_key, rank=None):
     '''
     parses a key, which may or may not contain a list
@@ -387,9 +398,9 @@ def parsekey(module, raw_key, rank=None):
         'ssh-rsa',
     ]
 
-    options    = None   # connection options
-    key        = None   # encrypted key string
-    key_type   = None   # type of ssh key
+    options = None   # connection options
+    key = None   # encrypted key string
+    key_type = None   # type of ssh key
     type_index = None   # index of keytype in key string|list
 
     # remove comment yaml escapes
@@ -398,7 +409,7 @@ def parsekey(module, raw_key, rank=None):
     # split key safely
     lex = shlex.shlex(raw_key)
     lex.quotes = []
-    lex.commenters = '' #keep comment hashes
+    lex.commenters = ''  # keep comment hashes
     lex.whitespace_split = True
     key_parts = list(lex)
 
@@ -430,6 +441,7 @@ def parsekey(module, raw_key, rank=None):
 
     return (key, key_type, options, comment, rank)
 
+
 def readfile(filename):
 
     if not os.path.isfile(filename):
@@ -441,6 +453,7 @@ def readfile(filename):
     finally:
         f.close()
 
+
 def parsekeys(module, lines):
     keys = {}
     for rank_index, line in enumerate(lines.splitlines(True)):
@@ -454,10 +467,11 @@ def parsekeys(module, lines):
             keys[line] = (line, 'skipped', None, None, rank_index)
     return keys
 
+
 def writefile(module, filename, content):
 
     fd, tmp_path = tempfile.mkstemp('', 'tmp', os.path.dirname(filename))
-    f = open(tmp_path,"w")
+    f = open(tmp_path, "w")
 
     try:
         f.write(content)
@@ -467,6 +481,7 @@ def writefile(module, filename, content):
     f.close()
     module.atomic_move(tmp_path, filename)
 
+
 def serialize(keys):
     lines = []
     new_keys = keys.values()
@@ -496,24 +511,26 @@ def serialize(keys):
                 key_line = key[0]
             else:
                 key_line = "%s%s %s %s\n" % (option_str, key_type, keyhash, comment)
-        except:
+        except Exception:
             key_line = key
         lines.append(key_line)
     return ''.join(lines)
 
+
 def enforce_state(module, params):
     """
     Add or remove key.
     """
 
-    user        = params["user"]
-    key         = params["key"]
-    path        = params.get("path", None)
-    manage_dir  = params.get("manage_dir", True)
-    state       = params.get("state", "present")
+    user = params["user"]
+    key = params["key"]
+    path = params.get("path", None)
+    manage_dir = params.get("manage_dir", True)
+    state = params.get("state", "present")
     key_options = params.get("key_options", None)
-    exclusive   = params.get("exclusive", False)
-    error_msg   = "Error getting key from: %s"
+    exclusive = params.get("exclusive", False)
+    comment = params.get("comment", None)
+    error_msg = "Error getting key from: %s"
 
     # if the key is a url, request it and use it as key source
     if key.startswith("http"):
@@ -559,6 +576,9 @@ def enforce_state(module, params):
             # rank here is the rank in the provided new keys, which may be unrelated to rank in existing_keys
             parsed_new_key = (parsed_new_key[0], parsed_new_key[1], parsed_options, parsed_new_key[3], parsed_new_key[4])
 
+        if comment is not None:
+            parsed_new_key = (parsed_new_key[0], parsed_new_key[1], parsed_new_key[2], comment, parsed_new_key[4])
+
         matched = False
         non_matching_keys = []
 
@@ -574,7 +594,7 @@ def enforce_state(module, params):
                 matched = True
 
         # handle idempotent state=present
-        if state=="present":
+        if state == "present":
             keys_to_exist.append(parsed_new_key[0])
             if len(non_matching_keys) > 0:
                 for non_matching_key in non_matching_keys:
@@ -590,7 +610,7 @@ def enforce_state(module, params):
                 existing_keys[parsed_new_key[0]] = (parsed_new_key[0], parsed_new_key[1], parsed_new_key[2], parsed_new_key[3], total_rank)
                 do_write = True
 
-        elif state=="absent":
+        elif state == "absent":
             if not matched:
                 continue
             del existing_keys[parsed_new_key[0]]
@@ -607,35 +627,41 @@ def enforce_state(module, params):
     if do_write:
         filename = keyfile(module, user, do_write, path, manage_dir)
         new_content = serialize(existing_keys)
-        diff = {
-            'before_header': params['keyfile'],
-            'after_header': filename,
-            'before': existing_content,
-            'after': new_content,
-        }
+
+        diff = None
+        if module._diff:
+            diff = {
+                'before_header': params['keyfile'],
+                'after_header': filename,
+                'before': existing_content,
+                'after': new_content,
+            }
+            params['diff'] = diff
+
         if module.check_mode:
             module.exit_json(changed=True, diff=diff)
         writefile(module, filename, new_content)
         params['changed'] = True
-        params['diff'] = diff
     else:
         if module.check_mode:
             module.exit_json(changed=False)
 
     return params
 
+
 def main():
     module = AnsibleModule(
-        argument_spec = dict(
-            user        = dict(required=True, type='str'),
-            key         = dict(required=True, type='str'),
-            path        = dict(required=False, type='str'),
-            manage_dir  = dict(required=False, type='bool', default=True),
-            state       = dict(default='present', choices=['absent','present']),
-            key_options = dict(required=False, type='str'),
-            unique      = dict(default=False, type='bool'),
-            exclusive   = dict(default=False, type='bool'),
-            validate_certs = dict(default=True, type='bool'),
+        argument_spec=dict(
+            user=dict(required=True, type='str'),
+            key=dict(required=True, type='str'),
+            path=dict(required=False, type='str'),
+            manage_dir=dict(required=False, type='bool', default=True),
+            state=dict(default='present', choices=['absent', 'present']),
+            key_options=dict(required=False, type='str'),
+            unique=dict(default=False, type='bool'),
+            exclusive=dict(default=False, type='bool'),
+            comment=dict(required=False, default=None, type='str'),
+            validate_certs=dict(default=True, type='bool'),
         ),
         supports_check_mode=True
     )
@@ -643,5 +669,6 @@ def main():
     results = enforce_state(module, module.params)
     module.exit_json(**results)
 
+
 if __name__ == '__main__':
     main()
diff --git a/test/integration/targets/authorized_key/defaults/main.yml b/test/integration/targets/authorized_key/defaults/main.yml
index a9184fd8a8b..d99e298fddd 100644
--- a/test/integration/targets/authorized_key/defaults/main.yml
+++ b/test/integration/targets/authorized_key/defaults/main.yml
@@ -1,39 +1,35 @@
----
-dss_key_basic: >
-  ssh-dss DATA_BASIC root@testing
-dss_key_unquoted_option: >
-  idle-timeout=5m ssh-dss DATA_UNQUOTED_OPTION root@testing
-dss_key_command: >
-  command="/bin/true" ssh-dss DATA_COMMAND root@testing
-dss_key_complex_command: >
-  command="echo foo 'bar baz'" ssh-dss DATA_COMPLEX_COMMAND root@testing
-dss_key_command_single_option: >
-  no-port-forwarding,command="/bin/true" ssh-dss DATA_COMMAND_SINGLE_OPTIONS root@testing
-dss_key_command_multiple_options: >
-  no-port-forwarding,idle-timeout=5m,command="/bin/true" ssh-dss DATA_COMMAND_MULTIPLE_OPTIONS root@testing
-dss_key_trailing: >
-  ssh-dss DATA_TRAILING root@testing foo bar baz
-rsa_key_basic: >
-  ssh-rsa DATA_BASIC root@testing
+dss_key_basic: ssh-dss DATA_BASIC root@testing
+dss_key_unquoted_option: idle-timeout=5m ssh-dss DATA_UNQUOTED_OPTION root@testing
+dss_key_command: command="/bin/true" ssh-dss DATA_COMMAND root@testing
+dss_key_complex_command: command="echo foo 'bar baz'" ssh-dss DATA_COMPLEX_COMMAND root@testing
+dss_key_command_single_option: no-port-forwarding,command="/bin/true" ssh-dss DATA_COMMAND_SINGLE_OPTIONS root@testing
+dss_key_command_multiple_options: no-port-forwarding,idle-timeout=5m,command="/bin/true" ssh-dss DATA_COMMAND_MULTIPLE_OPTIONS root@testing
+dss_key_trailing: ssh-dss DATA_TRAILING root@testing foo bar baz
+rsa_key_basic: ssh-rsa DATA_BASIC root@testing
+
 multiple_key_base: |
                     ssh-rsa DATA_BASIC 1@testing
                     ssh-dss DATA_TRAILING 2@testing foo bar baz
                     ssh-dss DATA_TRAILING 3@testing foo bar baz
                     ecdsa-sha2-nistp521 ECDSA_DATA 4@testing
+
 multiple_key_different_order: |
                               ssh-dss DATA_TRAILING 2@testing foo bar baz
                               ssh-dss DATA_TRAILING 3@testing foo bar baz
                               ssh-rsa DATA_BASIC 1@testing
                               ecdsa-sha2-nistp521 ECDSA_DATA 4@testing
+
 multiple_key_different_order_2: |
                                 ssh-dss DATA_TRAILING 2@testing foo bar baz
                                 ssh-rsa WHATEVER 2.5@testing
                                 ssh-dss DATA_TRAILING 3@testing foo bar baz
                                 ssh-rsa DATA_BASIC 1@testing
                                 ecdsa-sha2-nistp521 ECDSA_DATA 4@testing
+
 multiple_key_exclusive: |
                     ssh-rsa DATA_BASIC 1@testing
                     ecdsa-sha2-nistp521 ECDSA_DATA 4@testing
+
 multiple_keys_comments: |
   ssh-rsa DATA_BASIC 1@testing
   # I like adding comments yo-dude-this-is-not-a-key INVALID_DATA 2@testing
diff --git a/test/integration/targets/authorized_key/tasks/main.yml b/test/integration/targets/authorized_key/tasks/main.yml
index 3ea8206f434..14539873274 100644
--- a/test/integration/targets/authorized_key/tasks/main.yml
+++ b/test/integration/targets/authorized_key/tasks/main.yml
@@ -22,52 +22,59 @@
 
 
 - name: copy an existing file in place with comments
-  copy: src=existing_authorized_keys dest="{{output_dir|expanduser}}/authorized_keys"
+  copy:
+    src: existing_authorized_keys
+    dest: "{{ output_dir | expanduser }}/authorized_keys"
 
 - name: add multiple keys different order
   authorized_key:
     user: root
     key: "{{ multiple_key_different_order_2 }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: get the file content
-  shell: cat "{{output_dir|expanduser}}/authorized_keys"
+  shell: cat "{{ output_dir | expanduser }}/authorized_keys"
+  changed_when: no
   register: multiple_keys_existing
 
 - name: assert that the key was added and comments and ordering preserved
   assert:
     that:
-    - 'result.changed == True'
-    - '"# I like candy" in multiple_keys_existing.stdout'
-    - '"# I like candy" in multiple_keys_existing.stdout_lines[0]'
-    - '"ssh-rsa DATA_BASIC 1@testing" in multiple_keys_existing.stdout'
-    # The specific index is a little fragile, but I want to verify the line shows up
-    # as the 3rd line in the new entries after the existing entries and comments are preserved
-    - '"ssh-rsa DATA_BASIC 1@testing" in multiple_keys_existing.stdout_lines[7]'
+      - 'result.changed == True'
+      - '"# I like candy" in multiple_keys_existing.stdout'
+      - '"# I like candy" in multiple_keys_existing.stdout_lines[0]'
+      - '"ssh-rsa DATA_BASIC 1@testing" in multiple_keys_existing.stdout'
+      # The specific index is a little fragile, but I want to verify the line shows up
+      # as the 3rd line in the new entries after the existing entries and comments are preserved
+      - '"ssh-rsa DATA_BASIC 1@testing" in multiple_keys_existing.stdout_lines[7]'
 
 # start afresh
 
 - name: remove file foo.txt
-  file: path="{{output_dir|expanduser}}/authorized_keys" state=absent
+  file:
+    path: "{{ output_dir | expanduser }}/authorized_keys"
+    state: absent
 
 - name: touch the authorized_keys file
-  file: dest="{{output_dir}}/authorized_keys" state=touch
+  file:
+    dest: "{{ output_dir }}/authorized_keys"
+    state: touch
   register: result
 
 - name: assert that the authorized_keys file was created
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.state == "file"'
+      - 'result.changed == True'
+      - 'result.state == "file"'
 
 - name: add multiple keys
   authorized_key:
     user: root
     key: "{{ multiple_key_base }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
@@ -82,7 +89,7 @@
     user: root
     key: "{{ multiple_key_different_order }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
@@ -97,23 +104,23 @@
     user: root
     key: "{{ multiple_key_exclusive }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
     exclusive: true
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == multiple_key_exclusive'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == multiple_key_exclusive'
+      - 'result.key_options == None'
 
 - name: add multiple keys in different calls
   authorized_key:
     user: root
     key: "ecdsa-sha2-nistp521 ECDSA_DATA 4@testing"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: add multiple keys in different calls
@@ -121,38 +128,40 @@
     user: root
     key: "ssh-rsa DATA_BASIC 1@testing"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: get the file content
-  shell: cat "{{output_dir|expanduser}}/authorized_keys"
+  shell: cat "{{ output_dir | expanduser }}/authorized_keys"
+  changed_when: no
   register: multiple_keys_at_a_time
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == false'
-    - 'multiple_keys_at_a_time.stdout  == multiple_key_exclusive.strip()'
+      - 'result.changed == false'
+      - 'multiple_keys_at_a_time.stdout  == multiple_key_exclusive.strip()'
 
 - name: add multiple keys comment
   authorized_key:
     user: root
     key: "{{ multiple_keys_comments }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
     exclusive: true
   register: result
 
 - name: get the file content
-  shell: cat "{{output_dir|expanduser}}/authorized_keys"
+  shell: cat "{{ output_dir | expanduser }}/authorized_keys"
+  changed_when: no
   register: multiple_keys_comments
 
 - name: assert that the keys exist and comment only lines were not added
   assert:
     that:
-    - 'result.changed == False'
-    - 'multiple_keys_comments.stdout == multiple_key_exclusive.strip()'
-    - 'result.key_options == None'
+      - 'result.changed == False'
+      - 'multiple_keys_comments.stdout == multiple_key_exclusive.strip()'
+      - 'result.key_options == None'
 
 
 
@@ -160,86 +169,86 @@
 # basic ssh-dss key
 
 - name: add basic ssh-dss key
-  authorized_key: user=root key="{{ dss_key_basic }}" state=present path="{{output_dir|expanduser}}/authorized_keys"
+  authorized_key: user=root key="{{ dss_key_basic }}" state=present path="{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_basic'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_basic'
+      - 'result.key_options == None'
 
 - name: re-add basic ssh-dss key
-  authorized_key: user=root key="{{ dss_key_basic }}" state=present path="{{output_dir|expanduser}}/authorized_keys"
+  authorized_key: user=root key="{{ dss_key_basic }}" state=present path="{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # ssh-dss key with an unquoted option
 
 - name: add ssh-dss key with an unquoted option
-  authorized_key: 
+  authorized_key:
     user: root
     key: "{{ dss_key_unquoted_option }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_unquoted_option'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_unquoted_option'
+      - 'result.key_options == None'
 
 - name: re-add ssh-dss key with an unquoted option
   authorized_key:
     user: root
     key: "{{ dss_key_unquoted_option }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # ssh-dss key with a leading command="/bin/foo"
 
 - name: add ssh-dss key with a leading command
-  authorized_key: 
+  authorized_key:
     user: root
     key: "{{ dss_key_command }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_command'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_command'
+      - 'result.key_options == None'
 
 - name: re-add ssh-dss key with a leading command
   authorized_key:
     user: root
     key: "{{ dss_key_command }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # ssh-dss key with a complex quoted leading command
@@ -250,28 +259,28 @@
     user: root
     key: "{{ dss_key_complex_command }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_complex_command'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_complex_command'
+      - 'result.key_options == None'
 
 - name: re-add ssh-dss key with a complex quoted leading command
   authorized_key:
     user: root
     key: "{{ dss_key_complex_command }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # ssh-dss key with a command and a single option, which are
@@ -282,28 +291,28 @@
     user: root
     key: "{{ dss_key_command_single_option }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_command_single_option'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_command_single_option'
+      - 'result.key_options == None'
 
 - name: re-add ssh-dss key with a command and a single option
   authorized_key:
     user: root
     key: "{{ dss_key_command_single_option }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # ssh-dss key with a command and multiple other options
@@ -313,28 +322,28 @@
     user: root
     key: "{{ dss_key_command_multiple_options }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_command_multiple_options'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_command_multiple_options'
+      - 'result.key_options == None'
 
 - name: re-add ssh-dss key with a command and multiple options
   authorized_key:
     user: root
     key: "{{ dss_key_command_multiple_options }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # ssh-dss key with multiple trailing parts, which are space-
@@ -345,81 +354,132 @@
     user: root
     key: "{{ dss_key_trailing }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_trailing'
-    - 'result.key_options == None'
+      - 'result.changed == True'
+      - 'result.key == dss_key_trailing'
+      - 'result.key_options == None'
 
 - name: re-add ssh-dss key with trailing parts
   authorized_key:
     user: root
     key: "{{ dss_key_trailing }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that nothing changed
   assert:
     that:
-    - 'result.changed == False'
+      - 'result.changed == False'
 
 # -------------------------------------------------------------
 # basic ssh-dss key with mutliple permit-open options
 # https://github.com/ansible/ansible-modules-core/issues/1715
 
 - name: add basic ssh-dss key with multi-opts
-  authorized_key: 
-    user: root 
-    key: "{{ dss_key_basic }}" 
+  authorized_key:
+    user: root
+    key: "{{ dss_key_basic }}"
     key_options: 'no-agent-forwarding,no-X11-forwarding,permitopen="10.9.8.1:8080",permitopen="10.9.8.1:9001"'
-    state: present 
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    state: present
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
 
 - name: assert that the key with multi-opts was added
   assert:
     that:
-    - 'result.changed == True'
-    - 'result.key == dss_key_basic'
-    - 'result.key_options == "no-agent-forwarding,no-X11-forwarding,permitopen=\"10.9.8.1:8080\",permitopen=\"10.9.8.1:9001\""'
+      - 'result.changed == True'
+      - 'result.key == dss_key_basic'
+      - 'result.key_options == "no-agent-forwarding,no-X11-forwarding,permitopen=\"10.9.8.1:8080\",permitopen=\"10.9.8.1:9001\""'
 
 - name: get the file content
-  shell: cat "{{output_dir|expanduser}}/authorized_keys" | fgrep DATA_BASIC
+  shell: cat "{{ output_dir | expanduser }}/authorized_keys" | fgrep DATA_BASIC
+  changed_when: no
   register: content
 
 - name: validate content
   assert:
     that:
-        - 'content.stdout == "no-agent-forwarding,no-X11-forwarding,permitopen=\"10.9.8.1:8080\",permitopen=\"10.9.8.1:9001\" ssh-dss DATA_BASIC root@testing"'
+      - 'content.stdout == "no-agent-forwarding,no-X11-forwarding,permitopen=\"10.9.8.1:8080\",permitopen=\"10.9.8.1:9001\" ssh-dss DATA_BASIC root@testing"'
 
 # -------------------------------------------------------------
 # check mode
 
 - name: copy an existing file in place with comments
-  copy: src=existing_authorized_keys dest="{{output_dir|expanduser}}/authorized_keys"
+  copy:
+    src: existing_authorized_keys
+    dest: "{{ output_dir | expanduser }}/authorized_keys"
 
 - authorized_key:
     user: root
     key: "{{ multiple_key_different_order_2 }}"
     state: present
-    path: "{{output_dir|expanduser}}/authorized_keys"
+    path: "{{ output_dir | expanduser }}/authorized_keys"
   check_mode: True
   register: result
 
-- name: assert that the key would be added and that the diff is shown
-  assert:
-    that:
-      - 'result.changed'
-      - '"ssh-rsa WHATEVER 2.5@testing" in result.diff.after'
-
 - name: assert that the file was not changed
-  copy: src=existing_authorized_keys dest="{{output_dir|expanduser}}/authorized_keys"
+  copy:
+    src: existing_authorized_keys
+    dest: "{{ output_dir | expanduser }}/authorized_keys"
   register: result
+
 - assert:
     that:
       - 'result.changed == False'
+
+# -------------------------------------------------------------
+# comments
+
+- name: Add rsa key with existing comment
+  authorized_key:
+    user: root
+    key: "{{ rsa_key_basic }}"
+    state: present
+    path: "{{ output_dir | expanduser }}/authorized_keys"
+  register: result
+
+- name: Change the comment on an existing key
+  authorized_key:
+    user: root
+    key: "{{ rsa_key_basic }}"
+    comment: user@acme.com
+    state: present
+    path: "{{ output_dir | expanduser }}/authorized_keys"
+  register: result
+
+- name: get the file content
+  shell: cat "{{ output_dir | expanduser }}/authorized_keys" | fgrep DATA_BASIC
+  changed_when: no
+  register: content
+
+- name: Assert that comment on an existing key was changed
+  assert:
+    that:
+      - "'user@acme.com' in content.stdout"
+
+- name: Set the same key with comment to ensure no changes are reported
+  authorized_key:
+    user: root
+    key: "{{ rsa_key_basic }}"
+    comment: user@acme.com
+    state: present
+    path: "{{ output_dir | expanduser }}/authorized_keys"
+  register: result
+
+- name: Assert that no changes were made when running again
+  assert:
+    that:
+      - not result.changed
+
+- debug:
+    var: "{{ item }}"
+    verbosity: 1
+  with_items:
+    - result
+    - content
diff --git a/test/sanity/pep8/legacy-files.txt b/test/sanity/pep8/legacy-files.txt
index 8a0a374abe4..ad4d309d627 100644
--- a/test/sanity/pep8/legacy-files.txt
+++ b/test/sanity/pep8/legacy-files.txt
@@ -434,7 +434,6 @@ lib/ansible/modules/storage/zfs/zfs.py
 lib/ansible/modules/system/aix_inittab.py
 lib/ansible/modules/system/alternatives.py
 lib/ansible/modules/system/at.py
-lib/ansible/modules/system/authorized_key.py
 lib/ansible/modules/system/capabilities.py
 lib/ansible/modules/system/cron.py
 lib/ansible/modules/system/cronvar.py