Update documentation and remove TLS configuration options

Change-Id: I59b8627f700ca964c85c043529ccdb33973cfb08
Closes-Bug: #1851474

README.md

@@ -0,0 +1 @@
+src/README.md

src/README.md

@@ -4,12 +4,35 @@ This subordinate charm provides the Octavia Diskimage Retrofit tool
 
 # Usage
 
-There is a [section](https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-octavia.html) about Octavia in the [Deployment Guide](https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/).
+There is a [section in the Octavia][amphora-octavia-cdg] appendix in the
+[OpenStack Charms Deployment Guide][cdg] that describes how to deploy and use
+the charm.
 
-A [bundle overlay](https://github.com/openstack-charmers/openstack-bundles/blob/master/stable/overlays/loadbalancer-octavia.yaml) for use in conjunction with the [OpenStack Base bundle](https://jujucharms.com/openstack-base/) is also available.
+A [bundle overlay][octavia-bundle-overlay] for use in conjunction with the
+[OpenStack Base bundle][openstack-base-bundle] is also available.
+
+> **Note**: The charm relies on Glance image properties as provided by the
+  [Glance Simplestreams Sync Charm][charm-gss] for automatic discovery of the
+  most recent image, and as such is designed to be deployed as a subordinate to
+  it.
+
+> **Note**: When establishing connections to cloud services such as Glance and
+  Keystone in clouds that have TLS enabled, the system certificate store will
+  be used to verify the peer. It is the responsibility of the principle charm
+  to populate the system certificate store.
 
 # Bugs
 
-Please report bugs on [Launchpad](https://bugs.launchpad.net/charm-octavia-diskimage-retrofit/+filebug).
+Please report bugs on [Launchpad][lp-octavia-diskimage-retrofit].
 
-For general questions please refer to the OpenStack [Charm Guide](https://docs.openstack.org/charm-guide/latest/).
+For general questions please refer to the OpenStack [Charm Guide][cg].
+
+<!-- LINKS -->
+
+[cg]: https://docs.openstack.org/charm-guide/latest/
+[cdg]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/
+[amphora-octavia-cdg]: https://docs.openstack.org/project-deploy-guide/charm-deployment-guide/latest/app-octavia.html#amphora-image
+[octavia-bundle-overlay]: https://github.com/openstack-charmers/openstack-bundles/blob/master/stable/overlays/loadbalancer-octavia.yaml
+[openstack-base-bundle]: https://jujucharms.com/openstack-base/
+[charm-gss]: https://jaas.ai/glance-simplestreams-sync/
+[lp-octavia-diskimage-retrofit]: https://bugs.launchpad.net/charm-octavia-diskimage-retrofit/+filebug

src/layer.yaml

@@ -20,6 +20,9 @@ comment: |
 repo: https://github.com/openstack/charm-octavia-diskimage-retrofit
 config:
   deletes:
-    - verbose
+    - ssl_ca
+    - ssl_cert
+    - ssl_key
     - use-internal-endpoints
     - use-syslog
+    - verbose