I would like to use Automatic Horizontal Scaling in Jelastic, but this would only make sense if it could automatically update the relevant upstream in nginx.conf when a node is added/removed.
Example: Automatic Horizontal Scaling is triggered for my Node.js server application and a new node is added. It should also automatically update in each Nginx node's nginx.conf all upstreams where the Node.js master node's ip is specified.
How could this be achieved?
I have read all related docs such as Jelastic Automatic Horizontal Scaling and have not found a solution yet.
That is already the expected behaviour. I recommend to discuss with your hosting provider in case you've found a bug.
You can also potentially write your own logic using the onAfterScaleOut event.