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@ -23,7 +23,7 @@
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<link rel="top" title="Ansible v0.0.1 documentation" href="index.html" />
<link rel="next" title="Examples" href="examples.html" />
<link rel="next" title="API" href="api.html" />
<link rel="prev" title="YAML Scripts" href="YAMLScripts.html" />
</head>
<body>
@ -34,7 +34,7 @@
<a href="genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="examples.html" title="Examples"
<a href="api.html" title="API"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="YAMLScripts.html" title="YAML Scripts"
@ -61,7 +61,9 @@
<dd>Learn about how to select hosts</dd>
</dl>
</div>
<p>Playbooks are a completely different way to use ansible and are particularly awesome. They are the basis for a really simple configuration management and deployment system, unlike any that already exist, and one that is very well suited to deploying complex multi-machine applications. While you might run the main ansible program for ad-hoc tasks, playbooks are more likely to be kept in source control and used to push out your configuration or assure the configurations of your remote systems are in spec.</p>
<p>Playbooks are a completely different way to use ansible and are particularly awesome.</p>
<p>They are the basis for a really simple configuration management and multi-machine deployment system, unlike any that already exist, and one that is very well suited to deploying complex applications.</p>
<p>While you might run the main /usr/bin/ansible program for ad-hoc tasks, playbooks are more likely to be kept in source control and used to push out your configuration or assure the configurations of your remote systems are in spec.</p>
<div class="section" id="playbook-example">
<h2>Playbook Example<a class="headerlink" href="#playbook-example" title="Permalink to this headline"></a></h2>
<p>Playbooks are expressed in YAML format and have a minimum of syntax. Each playbook is composed
@ -89,30 +91,39 @@ back on the webservers group, etc:</p>
</div>
<div class="section" id="hosts-line">
<h2>Hosts line<a class="headerlink" href="#hosts-line" title="Permalink to this headline"></a></h2>
<p>The hosts line is alist of one or more groups or host patterns, seperated by colons, as
described in the &#8216;patterns&#8217; documentation.</p>
<p>The hosts line is a list of one or more groups or host patterns, seperated by colons, as
described in the &#8216;patterns&#8217; documentation. This is just like the first parameter to /usr/bin/ansible.</p>
</div>
<div class="section" id="vars-section">
<h2>Vars section<a class="headerlink" href="#vars-section" title="Permalink to this headline"></a></h2>
<p>A list of variables that can be used in the templates, action lines, or included files.
Variables are deferenced using <tt class="docutils literal"><span class="pre">jinja2</span></tt> syntax like this:</p>
<div class="highlight-python"><pre>{{ varname }}</pre>
</div>
<p>These variables will be pushed down to the managed systems for use in templating operations, where
the way to dereference them in templates is exactly the same.</p>
<p>A list of variables and values that can be used in the plays. These can be used in templates
or &#8216;action&#8217; lines and are dereferenced using <tt class="docutils literal"><span class="pre">`jinja2`</span></tt> syntax like this:</p>
<blockquote>
<div>{{ varname }}</div></blockquote>
<p>Further, if there are discovered variables about the system (say, if facter or ohai were
installed) these variables bubble up back into the playbook, and can be used on each
system just like explicitly set variables. Facter variables are prefixed with &#8216;<a href="#id1"><span class="problematic" id="id2">facter_</span></a>&#8216;
and Ohai variables are prefixed with &#8216;<a href="#id3"><span class="problematic" id="id4">ohai_</span></a>&#8216;.</p>
and Ohai variables are prefixed with &#8216;<a href="#id3"><span class="problematic" id="id4">ohai_</span></a>&#8216;. So for instance, if I wanted to write the
hostname into the /etc/motd file, I could say:</p>
<blockquote>
<div><ul class="simple">
<li>name: write the motd</li>
<li>action: template src=/srv/templates/motd.j2 dest=/etc/motd</li>
</ul>
</div></blockquote>
<p>And in /srv/templates/motd.j2::</p>
<div class="highlight-python"><pre>You are logged into {{ facter_hostname }}</pre>
</div>
<p>But we&#8217;re getting ahead of ourselves. Let&#8217;s talk about tasks.</p>
</div>
<div class="section" id="tasks-list">
<h2>Tasks list<a class="headerlink" href="#tasks-list" title="Permalink to this headline"></a></h2>
<p>Each play contains a list of tasks. Tasks are executed in order, one at a time, against
all machines matched by the play&#8217;s host pattern, before moving on to the next task.
Hosts with failed tasks are taken out of the rotation for the entire playbook. If things fail,
correct the problem and rerun. Modules other than command are idempotent, meaning if you
run them again, they will make the changes they are told to make to bring the system to
the desired state.</p>
all machines matched by the play&#8217;s host pattern, before moving on to the next task.</p>
<p>Hosts with failed tasks are taken out of the rotation for the entire playbook. If things fail,
simply correct the playbook file and rerun.</p>
<p>Modules other than command are idempotent, meaning if you run them again, they will make the
changes they are told to make to bring the system to the desired state.</p>
</div>
<div class="section" id="task-name-and-action">
<h2>Task name and action<a class="headerlink" href="#task-name-and-action" title="Permalink to this headline"></a></h2>
@ -120,25 +131,58 @@ the desired state.</p>
<p>The action line is the name of an ansible module followed by parameters. Usually these
are expressed in key=value form, except for the command module, which looks just like a Linux/Unix
command line. See the module documentation for more info.</p>
<p>Variables, as mentioned above, can be used in action lines. So if, hypothetically, you wanted
to make a directory on each system named after the hostname ... yeah, that&#8217;s I know silly ... you could
do it like so:</p>
<blockquote>
<div><ul class="simple">
<li>name: make a directory</li>
<li>action: mkdir /tmp/{{ facter_hostname }}</li>
</ul>
</div></blockquote>
</div>
<div class="section" id="notify-statements">
<h2>Notify statements<a class="headerlink" href="#notify-statements" title="Permalink to this headline"></a></h2>
<p>Nearly all modules are written to be &#8216;idempotent&#8217; and can signal when they have affected a change
on the remote system. If a notify statement is used, the named handler will be run against
each system where a change was effected, but NOT on systems where no change occurred.</p>
each system where a change was effected, but NOT on systems where no change occurred. This happens
after all of the tasks are run. For example, if notifying Apache and potentially replacing lots of
configuration files, you could have Apache restart just once, at the end of a run. If you need
Apache restarted in the middle of a run, you could just make a task for it, no harm done. Notifiers
are optional.</p>
</div>
<div class="section" id="handlers">
<h2>Handlers<a class="headerlink" href="#handlers" title="Permalink to this headline"></a></h2>
<p>Handlers are lists of tasks, not really any different from regular tasks, that are referenced
by name.</p>
by name. Handlers are what notifiers notify. If nothing notifies a handler, it will not run.
Regardless of how many things notify a handler, it will run only once, after all of the tasks
complete in a particular play.</p>
</div>
<div class="section" id="includes">
<h2>Includes<a class="headerlink" href="#includes" title="Permalink to this headline"></a></h2>
<p>Not all tasks have to be listed directly in the main file. An include file can contain
a list of tasks (in YAML) as well, optionally passing extra variables into the file.
Variables passed in can be deferenced like this:</p>
Variables passed in can be deferenced like this (assume a variable named &#8216;user&#8217;)</p>
<blockquote>
<div>{{ variable }}</div></blockquote>
<div>{{ user }}</div></blockquote>
<p>For instance, if deploying multiple wordpress instances, I could contain all of my tasks
in a wordpress.yml file, and use it like so:</p>
<blockquote>
<div><ul>
<li><dl class="first docutils">
<dt>tasks:</dt>
<dd><ul class="first last simple">
<li>include: wordpress.yml user=timmy</li>
<li>include: wordpress.yml user=alice</li>
<li>include: wordpress.yml user=bob</li>
</ul>
</dd>
</dl>
</li>
</ul>
</div></blockquote>
<p>In addition to the explicitly passed in parameters, all variables from the vars section
are also available.</p>
</div>
<div class="section" id="asynchronous-actions-and-polling">
<h2>Asynchronous Actions and Polling<a class="headerlink" href="#asynchronous-actions-and-polling" title="Permalink to this headline"></a></h2>
@ -179,8 +223,8 @@ Variables passed in can be deferenced like this:</p>
<p class="topless"><a href="YAMLScripts.html"
title="previous chapter">YAML Scripts</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="examples.html"
title="next chapter">Examples</a></p>
<p class="topless"><a href="api.html"
title="next chapter">API</a></p>
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="_sources/playbooks.txt"
@ -210,7 +254,7 @@ Variables passed in can be deferenced like this:</p>
<a href="genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="examples.html" title="Examples"
<a href="api.html" title="API"
>next</a> |</li>
<li class="right" >
<a href="YAMLScripts.html" title="YAML Scripts"