- Create cluster using blueprint
- Restart Ambari Server
- Install Ambari Agent on new host and register with server
- Add the new host via API request
- Start Ambari Agent on the new host
Result: Ambari Server accepts the scale request, but does not proceed to install/start components on the new host
The problem is that
AMBARI-22012 fixed a timing/ordering issue by introducing an executor, which is started on "cluster configured" event during blueprint cluster creation. If Ambari Server is restarted afterwards, the executor will stay stopped, hence tasks for scale requests are never executed.