I attended a workshop at the campus of  Microsoft France. The workshop presented the principles of Microservices and containers, and a couple of topics regarding docker, Kubernetes etc.

The first part of the workshop was just recalled the cloud basics. Then dive into the design principle for the applications before deploying with microservices in Azure. The main part of the presentation regarding the principle of microservices and finally share a real-life example on GitHub.

Cloud is ‘internet’, cloud providers provide different  ‘services’ via the cloud.  There are 3 types of cloud computing service models: 

• IaaS ( Infrastructure as a Service )
• PaaS( Platform as a Service )
• SaaS ( Software as a Service )

Each service offering provides a different level of virtualization and management responsibilities as shown in the following picture:

    Caption: different cloud computing service models from Microsoft’s documentation

Based on these models, there are also some concepts such as DaaS ( Database as a Service ) , CaaS ( Container as a Service ), MaaS ( Messaging as a Service ) etc.

The 12-factor app methodology was first presented by Adam Wiggins circa 2011 which aims to build SaaS app and cloud-native application addressed to design and build software as a service application with portability and resilience while deploying to the web, the principles generally are  :

• Allows to install and prepare the related environment with automation methods such as Azure Automation on Azure or AWS Opswork,  by using a declarative format to produce an identical result ( always reached the desired state )
• Be able to run in different OS environment with maximum portability
• Loosely coupled so that can be deployed in the cloud
• The development environment and production environment should be identical ( only allow to target to a different database but the structure remains the same )
• Allow continuous deployment so that to maximize the agility of deployments
• Highly scalable when peak time without changing the configuration tools

4 reasons to cut traditional application as a microservice application

There are 4 main reasons to recast or start at design phrase to apply the principle of microservice architecture :

• Using independent modules so that each can scale at their own space
• Possibility to use of different technologies in the same application. A great example is it is possible to call RESTful API service developed both in node.js and in .NET web API in the same application.
• High backward compatibility
• Easily managed the conflict of dependencies.

Caption: the difference between the application designing with monolithic architecture from microservices from https://docs.microsoft.com/en-us/azure/service-fabric/service-fabric-overview-microservices

Before starting build microservice :

The modern cloud-native applications expect to deploy with microservice architecture can be managed in a versioning control tool such as git and following the principle of ‘ a codebase = 1 repository’, and should isolate and declare the dependencies and system in an explicitly independent way. It will facilitate the maintenance and administration task.

At the same time, the codes should be separated with the configuration file, that means should pay attention to that: code should be only with variables but not the application or environment settings).

The application should be strictly stateless and share nothing with each module. Generally, the front site does not store any data,  so the data is always in the backend, and maybe exchange information by middleware such as implementing a RESTful API.

Each application must be autonomous in a ‘ self-contained’ way, so that each type of work by deploying one application, so general idea is ‘ one process one microservice’, the advantage of this idea is microservice can be well structured and we can  add or delete processes in an easy way, during the peak time, we can multiply the process by multiple the instance, during downtime, it is easy to realize rapid stop and start, so that the offline service back to normal rapidly.

Checking the integrity of the event and flow logs will be an important part while implementing the monitoring strategy. Since each microservice is an independent part but act as a whole system when they’re working together, the strategy to implement the logs will be based on the event. Microsoft Azure provides log analytics services and other metrics services while monitoring each microservices.  

The principles of microservice on Azure :

As Microsoft defined microservices architecture as a whole system contains a collection of small, autonomous services. Here are some principles while deploying microservice on Azure:

• One App server per microservice
• Each microservice has its own data persistent store ( backend  )
• Each microservice has its independent life cycle
•  No dependency on other modules
• Small and numerous as possible, facilitate the fast deployment in a more frequent way
• Strongly loosely coupled, as a small elastic unit within the distributed system
• Isolation from the  resources of applications

Microsoft documentation also provides their official guide to help user designing, building, and operating microservices on Azure, here is the link: https://docs.microsoft.com/en-us/azure/architecture/microservices/index

In action: real-life scenario regarding microservice on Azure

One of the most interesting parts of the workshop is to analyze a real-life example which builds with microservices on Azure, which is Microsoft eShop Container, this is a microservice architecture based application using .NET Core and Docker. In this project, it contains different types of microservices :

Caption: different types of microservices in eShop on containers example

This example was published on GitHub with the below link: https://github.com/dotnet-architecture/eShopOnContainers. The principles of this example will be explained with a simple example in another post: building microservices on Azure in upcoming days.

If you’re a  .Net developer or anyone who is experienced in Microsoft technical solutions, you will  definitely benefit from one excellent book which is recommended by Microsoft regarding microservice: .NET Microservices Architecture for Containerized .NET Applications,  it explains in detail how to develop the microservices architectural style, here is the link to download it: https://aka.ms/microservicesebook

“organizations which design systems  are constrained to produce designs which are copies of the communication structures of these organizations.”  – By M. Conway

(  Conway’s law in 1968 from http://www.melconway.com/Home/Conways_Law.html )

Next steps :

This post resumes the cloud basics and related concepts regarding microservices, actually, MS workshop has another part regarding dockers, containers solution on Microsoft Azure, DevOps and especially the principles of Kubernetes which I’ll present in my next post.

Personally, I enjoyed a lot the latest deployment methods and creative style while designing the application architecture brought by cloud computing. As cloud computing is boosting our business today, I hope the new normal will help us create more application with portability and resilience in the cloud.  Let’s stay tuned!