Setting up very large K8s cluster - Queries

Hi,

I am in a process of setting up a very large k8s cluster for user base of 100-200Mn.
And need some inputs on following queries:

  1. How many master servers should we use 3 or 5
  2. What should be master server h/w requirements (Ram, CPU, Disk size & type)
  3. Any specific n/w requirements to handle the traffic load
  4. Do we need to have the master server in data path (the live user access traffic will flow via Master servers) or master server should be kept out of data path and data should flow through an external LB (HA proxy/Nginx) and NodePort services. What is the best strategy for setting up this kind of Kubernetes clusters.
  5. Is the K8s LB recommended for production grade deployments? Where we won’t need an external LB.