doc/source/plugins.html - devstack - Gitiles

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         <div class='row pull-left'>
           <h2>Plugins <small>Add stuff</small></h2>
           <p>DevStack has a couple of plugin mechanisms to allow easily adding support for additional projects and features.</p>

           <h3>Extras.d Hooks</h3>
           <p>These relatively new hooks are an extension of the existing calls from <code>stack.sh</code> at the end of its run, plus <code>unstack.sh</code> and <code>clean.sh</code>.  A number of the higher-layer projects are implemented in DevStack using this mechanism.</p>

           <p>The script in <code>extras.d</code> is expected to be mostly a dispatcher to functions in a <code>lib/*</code> script.  The scripts are named with a zero-padded two digits sequence number prefix to control the order that the scripts are called, and with a suffix of <code>.sh</code>.  DevSack reserves for itself the sequence numbers 00 through 09 and 90 through 99.</p>

           <p>Below is a template that shows handlers for the possible command-line arguments:</p>

 <pre>
 # template.sh - DevStack extras.d dispatch script template

 # check for service enabled
 if is_service_enabled template; then

     if [[ "$1" == "source" ]]; then
         # Initial source of lib script
         source $TOP_DIR/lib/template
     fi

     if [[ "$1" == "stack" && "$2" == "pre-install" ]]; then
         # Set up system services
         echo_summary "Configuring system services Template"
         install_package cowsay

     elif [[ "$1" == "stack" && "$2" == "install" ]]; then
         # Perform installation of service source
         echo_summary "Installing Template"
         install_template

     elif [[ "$1" == "stack" && "$2" == "post-config" ]]; then
         # Configure after the other layer 1 and 2 services have been configured
         echo_summary "Configuring Template"
         configure_template

     elif [[ "$1" == "stack" && "$2" == "extra" ]]; then
         # Initialize and start the template service
         echo_summary "Initializing Template"
         ##init_template
     fi

     if [[ "$1" == "unstack" ]]; then
         # Shut down template services
         # no-op
         :
     fi

     if [[ "$1" == "clean" ]]; then
         # Remove state and transient data
         # Remember clean.sh first calls unstack.sh
         # no-op
         :
     fi
 fi
 </pre>

           <p>The arguments are:
           <ul>
             <li><strong>source</strong> - Called by each script that utilizes <code>extras.d</code> hooks; this replaces directly sourcing the <code>lib/*</code> script.</li>
             <li><strong>stack</strong> - Called by <code>stack.sh</code> three times for different phases of its run:
               <ul>
                 <li><strong>pre-install</strong> - Called after system (OS) setup is complete and before project source is installed.</li>
                 <li><strong>install</strong> - Called after the layer 1 and 2 projects source and their dependencies have been installed.</li>
                 <li><strong>post-config</strong> - Called after the layer 1 and 2 services have been configured.  All configuration files for enabled services should exist at this point.</li>
                 <li><strong>extra</strong> - Called near the end after layer 1 and 2 services have been started.  This is the existing hook and has not otherwise changed.</li>
               </ul></li>
             <li><strong>unstack</strong> - Called by <code>unstack.sh</code> before other services are shut down.</li>
             <li><strong>clean</strong> - Called by <code>clean.sh</code> before other services are cleaned, but after <code>unstack.sh</code> has been called.
           </ul></p>


           <h3>Hypervisor</h3>
           <p>Hypervisor plugins are fairly new and condense most hypervisor configuration into one place.</p>

           <p>The initial plugin implemented was for Docker support and is a useful template for the required support.  Plugins are placed in <code>lib/nova_plugins</code> and named <code>hypervisor-&lt;name&gt;</code> where <code>&lt;name&gt;</code> is the value of <code>VIRT_DRIVER</code>.  Plugins must define the following functions:</p>
             <ul>
               <li><code>install_nova_hypervisor</code> - install any external requirements</li>
               <li><code>configure_nova_hypervisor</code> - make configuration changes, including those to other services</li>
               <li><code>start_nova_hypervisor</code> - start any external services</li>
               <li><code>stop_nova_hypervisor</code> - stop any external services</li>
               <li><code>cleanup_nova_hypervisor</code> - remove transient data and cache</li>
             </ul>
         </div>

       </section>

       <footer>
         <p>&copy; Openstack Foundation 2011-2013 &mdash; An <a href="https://wiki.openstack.org/wiki/Programs">OpenStack program</a> created by <a href="http://www.rackspace.com/cloud/private_edition/">Rackspace Cloud Builders</a></p>
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   </body>
 </html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="utf-8">
	<title>DevStack - Plugins</title>
	<meta name="description" content="">
	<meta name="author" content="">

	<!-- Le HTML5 shim, for IE6-8 support of HTML elements -->
	<!--[if lt IE 9]>
	<script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
	<![endif]-->

	<!-- Le styles -->
	<link href="assets/css/bootstrap.css" rel="stylesheet">
	<link href="assets/css/local.css" rel="stylesheet">
	<style type="text/css">
	body { padding-top: 60px; }
	dd { padding: 10px; }
	</style>

	<!-- Le javascripts -->
	<script src="assets/js/jquery-1.7.1.min.js" type="text/javascript" charset="utf-8"></script>
	<script src="assets/js/bootstrap.js" type="text/javascript" charset="utf-8"></script>
	</head>

	<body>

	<div class="navbar navbar-fixed-top">
	<div class="navbar-inner">
	<div class="container">
	<a class="brand" href="/">DevStack</a>
	<ul class="nav pull-right">
	<li><a href="overview.html">Overview</a></li>
	<li><a href="changes.html">Changes</a></li>
	<li><a href="faq.html">FAQ</a></li>
	<li><a href="https://git.openstack.org/cgit/openstack-dev/devstack">git.openstack.org</a></li>
	<li><a href="https://review.openstack.org/#/q/status:open+project:openstack-dev/devstack,n,z">Gerrit</a></li>
	</ul>
	</div>
	</div>
	</div>

	<div class="container" id="home">

	<section id="faq" class="span12">

	<div class='row pull-left'>
	<h2>Plugins <small>Add stuff</small></h2>
	<p>DevStack has a couple of plugin mechanisms to allow easily adding support for additional projects and features.</p>

	<h3>Extras.d Hooks</h3>
	<p>These relatively new hooks are an extension of the existing calls from <code>stack.sh</code> at the end of its run, plus <code>unstack.sh</code> and <code>clean.sh</code>. A number of the higher-layer projects are implemented in DevStack using this mechanism.</p>

	<p>The script in <code>extras.d</code> is expected to be mostly a dispatcher to functions in a <code>lib/*</code> script. The scripts are named with a zero-padded two digits sequence number prefix to control the order that the scripts are called, and with a suffix of <code>.sh</code>. DevSack reserves for itself the sequence numbers 00 through 09 and 90 through 99.</p>

	<p>Below is a template that shows handlers for the possible command-line arguments:</p>

	<pre>
	# template.sh - DevStack extras.d dispatch script template

	# check for service enabled
	if is_service_enabled template; then

	if [[ "$1" == "source" ]]; then
	# Initial source of lib script
	source $TOP_DIR/lib/template
	fi

	if [[ "$1" == "stack" && "$2" == "pre-install" ]]; then
	# Set up system services
	echo_summary "Configuring system services Template"
	install_package cowsay

	elif [[ "$1" == "stack" && "$2" == "install" ]]; then
	# Perform installation of service source
	echo_summary "Installing Template"
	install_template

	elif [[ "$1" == "stack" && "$2" == "post-config" ]]; then
	# Configure after the other layer 1 and 2 services have been configured
	echo_summary "Configuring Template"
	configure_template

	elif [[ "$1" == "stack" && "$2" == "extra" ]]; then
	# Initialize and start the template service
	echo_summary "Initializing Template"
	##init_template
	fi

	if [[ "$1" == "unstack" ]]; then
	# Shut down template services
	# no-op
	:
	fi

	if [[ "$1" == "clean" ]]; then
	# Remove state and transient data
	# Remember clean.sh first calls unstack.sh
	# no-op
	:
	fi
	fi
	</pre>

	<p>The arguments are:
	<ul>
	<li><strong>source</strong> - Called by each script that utilizes <code>extras.d</code> hooks; this replaces directly sourcing the <code>lib/*</code> script.</li>
	<li><strong>stack</strong> - Called by <code>stack.sh</code> three times for different phases of its run:
	<ul>
	<li><strong>pre-install</strong> - Called after system (OS) setup is complete and before project source is installed.</li>
	<li><strong>install</strong> - Called after the layer 1 and 2 projects source and their dependencies have been installed.</li>
	<li><strong>post-config</strong> - Called after the layer 1 and 2 services have been configured. All configuration files for enabled services should exist at this point.</li>
	<li><strong>extra</strong> - Called near the end after layer 1 and 2 services have been started. This is the existing hook and has not otherwise changed.</li>
	</ul></li>
	<li><strong>unstack</strong> - Called by <code>unstack.sh</code> before other services are shut down.</li>
	<li><strong>clean</strong> - Called by <code>clean.sh</code> before other services are cleaned, but after <code>unstack.sh</code> has been called.
	</ul></p>


	<h3>Hypervisor</h3>
	<p>Hypervisor plugins are fairly new and condense most hypervisor configuration into one place.</p>

	<p>The initial plugin implemented was for Docker support and is a useful template for the required support. Plugins are placed in <code>lib/nova_plugins</code> and named <code>hypervisor-<name></code> where <code><name></code> is the value of <code>VIRT_DRIVER</code>. Plugins must define the following functions:</p>
	<ul>
	<li><code>install_nova_hypervisor</code> - install any external requirements</li>
	<li><code>configure_nova_hypervisor</code> - make configuration changes, including those to other services</li>
	<li><code>start_nova_hypervisor</code> - start any external services</li>
	<li><code>stop_nova_hypervisor</code> - stop any external services</li>
	<li><code>cleanup_nova_hypervisor</code> - remove transient data and cache</li>
	</ul>
	</div>

	</section>

	<footer>
	<p>© Openstack Foundation 2011-2013 — An <a href="https://wiki.openstack.org/wiki/Programs">OpenStack program</a> created by <a href="http://www.rackspace.com/cloud/private_edition/">Rackspace Cloud Builders</a></p>
	</footer>

	</div> <!-- /container -->
	</body>
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