Chapter 6

1. In a system consisting of many parts, failure of at least one part is only a matter of time. To avoid any downtime if such a situation occurs, one runs multiple instances of each component. If one of the instances fails, there are still others to serve the requests.
2. In a distributed application architecture, we have many moving parts. If Service A needs access to an instance of Service B, then it cannot know where to find such an instance. Instances can be on any random node of the cluster and they can even come and go as the orchestration engine sees fit, so we do not identify the target instance by, say, its IP address and port, but rather by its name and port. A DNS service knows how to resolve a service name into an IP address since it has all the information about all service instances running in the cluster.

3. A circuit breaker is a mechanism that helps to avoid...