Application Layer PDF

10 Application layer *[ Source: Intro to architecting systems for scale ]()* Separating out the web layer from the application layer (also known as platform layer) allows you to scale and configure both layers independently. Adding a new API results in adding application serve...

10 Application layer *[ Source: Intro to architecting systems for scale ]()* Separating out the web layer from the application layer (also known as platform layer) allows you to scale and configure both layers independently. Adding a new API results in adding application servers without necessarily adding additional web servers. The ** single responsibility principle advocates for small and autonomous services that ** work together. Small teams with small services can plan more aggressively for rapid growth. Workers in the application layer also help enable asynchronism. [ ]() Microservices Related to this discussion are microservices, which can be described as a suite of [ ]() independently deployable, small, modular services. Each service runs a unique process and communicates through a well-defined, lightweight mechanism to serve a business goal. 1 [ ]() Pinterest, for example, could have the following microservices: user profile, follower, feed, search, photo upload, etc. Service Discovery Systems such as Consul, Etcd, and Zookeeper can help services find each other by [ ]() [ ]() [ ]() keeping track of registered names, addresses, and ports. Health checks help verify [ ]() service integrity and are often done using an HTTP endpoint. Both Consul and Etcd [ ]() have a built in key-value store that can be useful for storing config values and other [ ]() shared data. Disadvantage(s): application layer Adding an application layer with loosely coupled services requires a different approach from an architectural, operations, and process viewpoint (vs a monolithic system). Microservices can add complexity in terms of deployments and operations.