mirror of https://github.com/ansible/ansible.git
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
52 lines
2.0 KiB
ReStructuredText
52 lines
2.0 KiB
ReStructuredText
Check Mode ("Dry Run")
|
|
======================
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
When ansible-playbook is executed with --check it will not make any changes on remote systems. Instead, any module
|
|
instrumented to support 'check mode' (which contains the primary core modules, but it is not required that all modules do
|
|
this) will report what changes they would have made. Other modules that do not support check mode will also take no
|
|
action, but just will not report what changes they might have made.
|
|
|
|
Check mode is just a simulation, and if you have steps that use conditionals that depend on the results of prior commands,
|
|
it may be less useful for you. However it is great for one-node-at-time basic configuration management use cases.
|
|
|
|
Example::
|
|
|
|
ansible-playbook foo.yml --check
|
|
|
|
Running a task in check mode
|
|
````````````````````````````
|
|
|
|
.. versionadded:: 1.3
|
|
|
|
Sometimes you may want to have a task to be executed even in check
|
|
mode. To achieve this, use the `always_run` clause on the task. Its
|
|
value is a Jinja2 expression, just like the `when` clause. In simple
|
|
cases a boolean YAML value would be sufficient as a value.
|
|
|
|
Example::
|
|
|
|
tasks:
|
|
|
|
- name: this task is run even in check mode
|
|
command: /something/to/run --even-in-check-mode
|
|
always_run: yes
|
|
|
|
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.
|
|
|
|
|
|
Showing Differences with --diff
|
|
```````````````````````````````
|
|
|
|
.. versionadded:: 1.1
|
|
|
|
The --diff option to ansible-playbook works great with --check (detailed above) but can also be used by itself. When this flag is supplied, if any templated files on the remote system are changed, and the ansible-playbook CLI will report back
|
|
the textual changes made to the file (or, if used with --check, the changes that would have been made). Since the diff
|
|
feature produces a large amount of output, it is best used when checking a single host at a time, like so::
|
|
|
|
ansible-playbook foo.yml --check --diff --limit foo.example.com
|
|
|