changing enable-sriov=false does not stop or disable sriov

By default sriov is not enabled in this charm, but can easily enabled by running the following command

    juju config neutron-openvswitch enable-sriov=true

This will install, and enable sriov as per all the templates, and works as expected. However, when we then use the same command to disable sriov, it doesn't seem to change any configuration. So the command for reference is

    juju config neutron-openvswitch enable-sriov=false

Before enabling sriov, there are no files in /etc/ that have sriov in the file, or any files that have sriov in the filename.

After installation and configuration change

The files below have the sriov inside their files

root@juju-5266de-bug-test-1:/etc# egrep -r -i sriov *
default/neutron-openvswitch-networking-sriov:# auto - Set sriov_numvfs to value of sriov_totalvfs for each interface
default/neutron-openvswitch-networking-sriov:# N - Set sriov_numvfs on all interfaces to N or value of sriov_totalvfs
default/neutron-openvswitch-networking-sriov:# if sriov_totalvfs is less than N for that interface
init/neutron-openvswitch-networking-sriov.conf:description "Configure SRIOV Virtual Functions"
init/neutron-openvswitch-networking-sriov.conf: [ -x "/usr/local/bin/neutron-openvswitch-networking-sriov.sh" ] || exit 0
init/neutron-openvswitch-networking-sriov.conf: exec /usr/local/bin/neutron-openvswitch-networking-sriov.sh start
init.d/neutron-sriov-agent:# Provides: neutron-sriov-agent
init.d/neutron-sriov-agent:# Short-Description: Neutron SRIOV Agent
init.d/neutron-sriov-agent:# Description: SRIOV agent for OpenStack Neutron
init.d/neutron-sriov-agent:DESC="OpenStack Neutron SRIOV Plugin Agent"
init.d/neutron-sriov-agent:NAME=${PROJECT_NAME}-sriov-agent
init.d/neutron-sriov-agent:DAEMON=/usr/bin/neutron-sriov-nic-agent
init.d/neutron-sriov-agent:DAEMON_ARGS="--config-file=/etc/neutron/plugins/ml2/sriov_agent.ini"
neutron/plugins/ml2/sriov_agent.ini:[sriov_nic]

and the following files have sriov in their name

root@juju-5266de-bug-test-1:/etc# find | grep -i sriov
./systemd/system/network-online.target.wants/neutron-openvswitch-networking-sriov.service
./systemd/system/multi-user.target.wants/neutron-openvswitch-networking-sriov.service
./systemd/system/multi-user.target.wants/neutron-sriov-agent.service
./rc4.d/S01neutron-sriov-agent
./rc2.d/S01neutron-sriov-agent
./init/neutron-openvswitch-networking-sriov.conf
./rc6.d/K01neutron-sriov-agent
./rc3.d/S01neutron-sriov-agent
./rc1.d/K01neutron-sriov-agent
./default/neutron-openvswitch-networking-sriov
./rc0.d/K01neutron-sriov-agent
./rc5.d/S01neutron-sriov-agent
./neutron/plugins/ml2/sriov_agent.ini
./init.d/neutron-sriov-agent

In order to enable SRIOV /ect/default/neutron-openvswitch-networking-sriov needs to be changed, such that the following change would need to be made

--- /etc/default/neutron-openvswitch-networking-sriov 2020-01-13 11:44:32.769600981 +0000
+++ /etc/default/neutron-openvswitch-networking-sriov.new 2020-01-13 12:34:45.733054783 +0000
@@ -1,5 +1,5 @@
 # Set to 1 to configure Virtual Functions on system startup.
-ENABLE=1
+ENABLE=0
 # Blanket configuration for number of Virtual Functions across all NICs
 #
 # Possible configurations:

Then the service neutron-sriov-agent needs to be disabled and stopped if it's running

For example, if it's been enabled, and then you disable and re-enable, the service for enabling the Neutron SRIOV plugin agent is restarted. There is no indication of the service being stopped when sriov is disabled

Steps to rectify

1. Expect the updated config above config
2. Stop and disable neutron-openvswitch-networking-sriov service
3. Stop and disable neutron-sriov-agent service
4. `/usr/local/bin/neutron-openvswitch-networking-sriov.sh --stop` may need to be run