Scaling your Kubernetes cluster
To support more traffic and more applications, your Kubernetes cluster may need to grow beyond its initial size. You can use both manual methods and dynamic programmed methods to do this, especially if you are working with a cloud-based Kubernetes cluster. To scale out an application, you need to control two dimensions: the number of pods running a particular application and the number of nodes in a cluster. You can't scale the number of pods infinitely on a cluster with the same number of nodes; practical limits related to CPU, memory, and network concerns will ultimately demand that the cluster scales out the number of nodes as well.
The method that's used to scale out a cluster will vary considerably, depending on the cloud vendor and Kubernetes distribution. The Kubernetes documentation explains both the general process and some specific instructions for clusters running in the Google and Microsoft Azure clouds: