I have just started learning about kubernetes and its concepts, so sorry if this is a lame question, however, I cannot seem to find the answer anywhere.
I understand that a node is a VM or a physical machine where the processes actually take place. Correct me if I am wrong, but what I have learnt is that kubernetes itself does not manipulate the number of nodes assigned to it. Therefore, I guess, if I want to scale up my application, I would need to add additional nodes to the cluster manually or by using an external cluster autoscaler.
So, if I have a cluster with two nodes (1 CPU each) all of the containers processes will take place on those two CPUs. If I have 4 replica sets of my pots, they all will be running on those 2 CPUs (2 replicas on each of the CPUs I guess).
Will there be any difference if I have 2, or 4, or 8 replica sets other than providing better roll-outs and more fault tolerance?
In general, is there any sense of having more replica sets than CPUs on the nodes?
And last, if a cluster autoscaler is enabled, would the number of replica sets effect the number of nodes?