<!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="http://github.com/openstack-dev/devstack">GitHub</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> </html>