Add a note on default values of globals
Add a note on default values of globals in plugin settings
Change-Id: I0d5d3a7e0597abe7e2401f8bae30ccc5682eab03
diff --git a/doc/source/plugins.rst b/doc/source/plugins.rst
index 5a61063..c4ed228 100644
--- a/doc/source/plugins.rst
+++ b/doc/source/plugins.rst
@@ -113,6 +113,11 @@
services using ``run_process`` as it only works with enabled
services.
+ Be careful to allow users to override global-variables for
+ customizing their environment. Usually it is best to provide a
+ default value only if the variable is unset or empty; e.g. in bash
+ syntax ``FOO=${FOO:-default}``.
+
- ``plugin.sh`` - the actual plugin. It will be executed by devstack
during it's run. The run order will be done in the registration
order for these plugins, and will occur immediately after all in