schema: Log debug instead of warning when jsonschema is not available.

When operating in expected path, cloud-init should avoid logging with
warning. That causes 'WARNING' messages in /var/log/cloud-init.log.
By default, warnings also go to the console.

Since jsonschema is a optional dependency, and not present on xenial
and zesty, cloud-init should not warn there.

Also here:
* Add a test to integration tests to assert that there are no
  warnings in /var/log/cloud-init.log.
* Update one integration test that did show warning and the related
  documentation and examples.

LP: #1724354

1 files changed, 2 insertions, 1 deletions

diff --git a/cloudinit/config/cc_users_groups.py b/cloudinit/config/cc_users_groups.py
index b80d1d36..f363000d 100644
--- a/cloudinit/config/cc_users_groups.py
+++ b/cloudinit/config/cc_users_groups.py
@@ -15,7 +15,8 @@ options, see the ``Including users and groups`` config example.
 Groups to add to the system can be specified as a list under the ``groups``
 key. Each entry in the list should either contain a the group name as a string,
 or a dictionary with the group name as the key and a list of users who should
-be members of the group as the value.
+be members of the group as the value. **Note**: Groups are added before users,
+so any users in a group list must already exist on the system.
 
 The ``users`` config key takes a list of users to configure. The first entry in
 this list is used as the default user for the system. To preserve the standard