Adds 'ansible_check_mode' boolean magic variable

* Makes it possible to pass any options variable to VariableManager
  by changing `load_options_vars(options)` in `lib/ansible/utils/vars.py`

docsite/rst/playbooks_checkmode.rst

@@ -38,7 +38,25 @@ Example::
 
 As a reminder, a task with a `when` clause evaluated to false, will
 still be skipped even if it has a `always_run` clause evaluated to
-true.
+true. 
+
+Also if you want to skip, or ignore errors on some tasks in check mode
+you can use a boolean magic variable `ansible_check_mode` (added in version 2.1)
+which will be set to `True` during check mode.
+
+Example::
+
+    tasks:
+
+      - name: this task will be skipped in check mode
+        git: repo=ssh://git@github.com/mylogin/hello.git dest=/home/mylogin/hello
+        when: not ansible_check_mode
+
+      - name: this task will ignore errors in check mode
+        git: repo=ssh://git@github.com/mylogin/hello.git dest=/home/mylogin/hello
+        ignore_errors: "{{ ansible_check_mode }}"
+
+
 
 .. _diff_mode:
 

docsite/rst/playbooks_variables.rst

@@ -674,7 +674,9 @@ Don't worry about any of this unless you think you need it.  You'll know when yo
 
 Also available, ``inventory_dir`` is the pathname of the directory holding Ansible's inventory host file, ``inventory_file`` is the pathname and the filename pointing to the Ansible's inventory host file.
 
-And finally, ``role_path`` will return the current role's pathname (since 1.8). This will only work inside a role.
+We then have ``role_path`` which will return the current role's pathname (since 1.8). This will only work inside a role.
+
+And finally, ``ansible_check_mode`` (added in version 2.1), a boolean magic variable which will be set to ``True`` if you run Ansible with ``--check``.
 
 .. _variable_file_separation_details: