Sometimes, application-level parallelism is not enough, and things that seem simple in development can become complex during deployment. Distributed systems provide a number of challenges not found when developing on a single machine. These applications have added complexity for things such as monitoring, writing applications that require strong consistency guarantees, and service discovery. In addition, you must always be mindful of single points of failure, such as a database. Otherwise your distributed applications can fail when this single component fails.
This chapter will explore methods of managing distributed data, orchestration, containerization, metrics, and monitoring. These will become part of your toolbox for writing and maintaining microservices and large distributed applications.