Node and Cluster are two critical concepts in Microsoft Azure Service Fabric.
Node: Node is like a run-time process in Azure service fabric. We can consider the node as a physical machine or VM in service fabric. We can deploy our service fabric application in one-node to the n-node system.
Cluster: Group of nodes called a cluster for a highly available and reliable environment to run our applications. A single cluster can have n number of nodes and each node in the cluster connect to another node as shown below.