Applications have become specific service oriented and lighter, with the requirement to perform across multiple environments, including on the cloud and on devices with lower processing power. As computing evolved to deployments onto native-cloud and serverless architecture, there was a need for lighter software applications that could be:
Microservice enabled legacy technology solution stacks or monolithic applications to be broken into smaller logical units/parts that can run independently on cloud environments, allowing these complex applications to be quickly tested and deployed reliably.
Microservices being loosely coupled and independently deployable smaller services, needed a platform that supported lightweight deployable capabilities. Container technology emerged as the preferred choice as a deployment platform for microservices due to characteristics like being – Light, Modular, Portable.
A Container is a logical packaging of the microservice/application, isolating it from the environment in which it runs. This allows container-based microservices/applications to be deployed with ease, regardless of the target environment which could be a private data center, the public cloud, or even a personal computer.
A single container can be used to run a microservice or even a software process to a larger application. The container consists of all the necessary executables, binary code, libraries, and configuration files.
Speed of delivery - Microservices allows developers to use any programming language that they are comfortable with. Additionally, as developers deal with a smaller codebase as compared to a large monolithic application the accompanying complexities and dependencies are low. This supports the DevOps and CI/CD development approaches well. A complete application, normally consisting of multiple microservice instances can be built, tested, and deployed quickly.
Solution benefits – As microservices communicate using language-neutral application programming interfaces (APIs) such as Representational State Transfer (REST), there is no need to align underlying performance or architecture of other microservices. This allows multiple options available to developers, for example, data from a microservice can be stored into a combination of NoSQL database, MongoDB, MySQL or Cloudant, allowing the application and developers to take advantage of the most appropriate database to store different data types.
Additionally, unlike in monolithic applications a portion of the application failing due to a bug or error does not make the whole application crash when you deploy through microservices. The microservices with bugs and errors can be quickly identified, corrected, and deployed. This would have been more complicated in a monolithic application as the whole application would need to be debugged, corrected, and recompiled.
Microservices are deployed using VM or Containers. Containers are the preferred deployment route for microservices as containers are lighter, portable, and modular. The microservice code is packaged into a container image and deployed as a container service. This approach allows for quick scaling of container instances and orchestration tools like Kubernetes helps manage a cluster of containers as a single logical system. Large implementations run across multiple hosts with orchestration tools facilitating discovery, replication, and management of the cluster.
Microservices is an architectural style that structures an application as a collection of loosely coupled services that are fine-grained, and the protocols are lightweight. Container technology is the preferred choice as a deployment platform for microservices. The combination of the container and microservice packaged as one unit of execution, contains all the dependencies for underlying operating system, platform, framework, and runtime. Containers encapsulate discrete components of application logic through microservices, provisioned only with the minimal resources needed to do their job.