Can you specify on which host a scaled container needs to be run?
So if I have a container on host 1 and I want to scale it, can I specify on which host those new containers should be launched? So I can scale a container in a datacenter near a customer ?
There are tools that lets you orchestrate when, how and what to scale. There are many, but Kubernetes (k8s) and Mesosphere seems quite popular.
Docker engine by itself is not scalable. Use a cluster manager, Kubernetes being the most commonly used.