Microservices

Question 1

What is the role of an API gateway?

Answer 1

An API gateway acts as a middleware and is used to manage and organize API calls from outside the client, as well as authorize and authenticate calls

Question 1

What is a fuse mechanism?

Answer 1

The fuse mechanism is used to prevent an avalanche, the cascading failures of multiple services, by returning a default value rather than having the program fail entirely

Question 2

How do microservices communicate with one another

Answer 2

Microservices are able to communicate with one another using APIs and HTTP

Question 3

What are the two methods to scale microservice

Answer 3

1. Horizontal Scalability - adding more servers to run your service
2. Vertical Scalability - increasing the power/storage in your servers to be able to run services

Question 4

What is a circuit breaker?

Answer 4

Similar to a fuse, a circuit break prevents a cascading failure once an exception has been thrown and provides a default service to prevent the service from crashing

Question 5

What is Hystrix

Answer 5

Hystrix is a circuit breaker which isolates failure and prevents errors from cascading across microservices
(Annotation: @HystrixCommand(fallbackMethod = “…”)

Question 6

What is versioning?

Answer 6

Versioning is used to differentiate between different versions of APIs which may have been updated to accommodate for design changes

Question 7

What is HikariCP used for?

Answer 7

Hikari is a database connection pool used to store database connection so that they can be reused when needed

Question 8

How do you make multiple service calls simultaneously?

Answer 8

Using reactive programming and Spring WebClient