Allow devstack plugins to specify prereq packages
We offer main devstack components the ability to install their own
system package preqreqs via files/{debs, rpms}/$service. This adds
similar functionality for plugins, who can now do the same in their
own tree at ./devstack/files/{debs, rpms}/$plugin.
Change-Id: I63af8dc54c75a6e80ca4b2a96c76233a0795aabb
diff --git a/doc/source/plugins.rst b/doc/source/plugins.rst
index 5d6d3f1..a9153df 100644
--- a/doc/source/plugins.rst
+++ b/doc/source/plugins.rst
@@ -154,3 +154,24 @@
- ``start_nova_hypervisor`` - start any external services
- ``stop_nova_hypervisor`` - stop any external services
- ``cleanup_nova_hypervisor`` - remove transient data and cache
+
+System Packages
+===============
+
+Devstack provides a framework for getting packages installed at an early
+phase of its execution. This packages may be defined in a plugin as files
+that contain new-line separated lists of packages required by the plugin
+
+Supported packaging systems include apt and yum across multiple distributions.
+To enable a plugin to hook into this and install package dependencies, packages
+may be listed at the following locations in the top-level of the plugin
+repository:
+
+- ``./devstack/files/debs/$plugin_name`` - Packages to install when running
+ on Ubuntu, Debian or Linux Mint.
+
+- ``./devstack/files/rpms/$plugin_name`` - Packages to install when running
+ on Red Hat, Fedora, CentOS or XenServer.
+
+- ``./devstack/files/rpms-suse/$plugin_name`` - Packages to install when
+ running on SUSE Linux or openSUSE.