Flag 'use_gateway' cannot be provided without gateway" error when discarding cluster changes

[Alexey. Kalashnikov]

Environment configuration:
[root@nailgun ~]# shotgun2 short-report
cat /etc/fuel_build_id:
 417
cat /etc/fuel_build_number:
 417
cat /etc/fuel_release:
 9.0
cat /etc/fuel_openstack_version:
 mitaka-9.0

steps to reproduce:
1. create environment (default wizard settings), add some nodes and deploy the env
2. go to Networks tab, add a new node network group
3. click Show All Networks checkbox to observe all node network groups on the one page
4. click Load Deployed Settings button
5. delete created node group
6. go to dashboard and discard changes

Actual result:
Changes were not discarded, error message in console:
PUT http://172.16.17.43:8417/api/clusters/1/network_configuration/neutron 400 (Bad Request)
Uncaught TypeError: newNetworkConfiguration.get(...).get is not a function
PUT http://172.16.17.43:8417/api/clusters/1/network_configuration/neutron 400 (Bad Request)
Uncaught TypeError: newNetworkConfiguration.get(...).get is not a function

Expected result:
Changes were discarded

[Aleksey Kasatkin (alekseyk-ru)]

AFAIC, it's not HIGH. It's not a common case when user adds then deletes a node group. Much more common is when user just adds a node group.

[Julia Aranovich (jkirnosova)]

So, the issue looks like a feature: restoring of network configuration should be executed in backend to take into account all corner cases like changes in node network groups, VIPs, etc.

[Aleksey Kasatkin (alekseyk-ru)]

A separate API handler can be implemented that will deal with restoring of environment configuration. So that VIPs, network template, node network groups, etc. can be taken into account. As VIPs depend on plugins, it's better to restore environment attributes together with network settings in one call.