Goal: 

I as a human deployer using the RHOSO installer want to be able to switch individual nova service types between eventlet and native threading mode.

• Background *

Upstream allows switching the mode via passing env variables to the service. The RHOSO installer does not allow such a thing via the current configuration interfaces. Originally the upstream direction was chosen doe to the limitations of oslo.service and nova that does not allowed to read configurations before the concurrency mode needed to be selected for a service.

• Solution *
  We need to investigate different directions:
• a) Does oslo.service now support better methods to decide on the concurrency mode that could be used to allow the human deployer to define the mode in the configuration file?
• b) Does the RHOSO technical leadership would be OK to expose an interface that allows passing env variables to deployments / statefulsets / podman pods?

Acceptance Criteria:

• Technical direction is decide and the solution is agreed with the respective parties (nova core team or the operator round table)
• Solution is developed in the selected module(s) based on the agreement (nova, oslo.service, nova-operator, edpm-ansible)