Microservices Interview Questions and Answers

Docker helps in many ways for microservices architecture.

1. In a microservice architecture, there can be many different services written in different languages. So a developer might have to setup few services along with its dependency and platform requirements. This becomes difficult with the growing number of services in an ecosystem. However, this becomes very easy if these services run inside a Docker container.

2. Running services inside a container also give a similar setup across all the environments, i.e development, staging and production.

3. Docker also helps in scaling along with container orchestration.

4. Docker helps to upgrade the underlying language very easily. We can save many man-hours.

5. Docker helps to onboard the engineers fast.

6. Docker also helps to reduce the dependencies on IT Teams to set up and manage the different kind of environment required.

How would you manage application configuration in microservice running in a container?

As container based deployment involves a single image per microservice, it is a bad idea to bundle the configuration along with the image.

This approach is not at all scalable because we might have multiple environments and also we might have to take care of geographically distributed deployments where we might have different configurations as well.

Also, when there are application and cron application as part of the same codebase, it might need to take additional care on production as it might have repercussions how the crons are architected.

To solve this, we can put all our configuration in a centralized config service which can be queried by the application for all its configurations at the runtime. Spring cloud is one of the example services which provides this facility.

It also helps to secure the information, as the configuration might have passwords or access to reports or database access controls. Only trusted parties should be allowed to access these details for security reasons.

What is container orchestration and how does it helps in a microservice architecture?

In a production environment, you don’t just deal with the application code/application server. You need to deal with API Gateway, Proxy Servers, SSL terminators, Application Servers, Database Servers, Caching Services, and other dependent services.

As in modern microservice architecture where each microservice runs in a separate container, deploying and managing these containers is very challenging and might be error-prone.

Container orchestration solves this problem by managing the life cycle of a container and allows us to automate the container deployments.

It also helps in scaling the application where it can easily bring up a few containers. Whenever there is a high load on the application and once the load goes down. it can scale down as well by bringing down the containers. It is helpful to adjust cost based on requirements.

Also in some cases, it takes care of internal networking between services so that you need not make any extra effort to do so. It also helps us to replicate or deploy the docker images at runtime without worrying about the resources. If you need more resources, you can configure that in orchestration services and it will be available/deployed on production servers within minutes.