Add 'unverified_modules' config option and skip unverified modules

Config modules are able to declare distros that they were verified
to run on by setting 'distros' as a list in the config module.

Previously, if a module was configured to run and the running distro was not
listed as supported, it would run anyway, and a warning would be written.

Now, we change the behavior to skip those modules.

The distro (or user) can specify that a given list of modules should run anyway
by declaring the 'unverified_modules' config variable.

run_once modules will be run without this filter (ie, expecting that the user
explicitly wanted to run it).

1 files changed, 10 insertions, 0 deletions

diff --git a/doc/examples/cloud-config.txt b/doc/examples/cloud-config.txt
index 61fa6065..ed4eb7fc 100644
--- a/doc/examples/cloud-config.txt
+++ b/doc/examples/cloud-config.txt
@@ -319,6 +319,16 @@ cloud_config_modules:
  - runcmd
  - byobu
 
+# unverified_modules: []
+# if a config module declares a set of distros as supported then it will be
+# skipped if running on a different distro.  to override this sanity check,
+# provide a list of modules that should be run anyway in 'unverified_modules'.
+# The default is an empty list (ie, trust modules).
+#
+# Example:
+#   unverified_modules: ['apt-update-upgrade']
+#   default: []
+
 # ssh_import_id: [ user1, user2 ]
 # ssh_import_id will feed the list in that variable to
 #  ssh-import-id, so that public keys stored in launchpad