I would like to know, if it is a good idea to use several threads in a CF Garden Container. My understanding, according to 12 Factor apps, was that one container one process and one thread. But, after a discussion with a colleague I'm not so sure anymore.
So, Is it a good idea to use thread pools in a CF.
Best regards
How many threads you use is entirely up to you. Cloud Foundry adds no special distinctions about the number of threads your application can use. Like any environment, the number of threads you can use will depend on resources available and any general advice about thread usage for your language and runtime should apply for running your application on Cloud Foundry.
The only Cloud Foundry specific advice I would offer is to make sure that your app can scale out by adding more instances of your app (as opposed to scaling up RAM & CPU). If you can easily add more instances of your app then it will scale nicely on CF by using cf scale -i <num> (technically you can also cf scale the RAM, but you'll quickly hit limits going that route).
Hope that helps!