Thursday, November 25, 2021

Embracing Microservices Design: A practical guide to revealing anti-patterns and architectural pitfalls to avoid microservices fallacies | Book Review

I was recently invited to review the book Embracing Microservices Design by Ovais Mehboob 

Ahmed Khan, Nabil Siddique, Timothy Oleson.

Fantastic book, as the book preface very well stated Embracing Microservices Design targets architects and developers who want to design and build microservices-based applications following the right principles, practices, and patterns and avoiding the fallacies and anti-patterns that may lead to bad implementation.

This is an excellent book for anyone who is interested to learn about microservices design patterns or is planning to work on microservices on their new project, or even looking to move their existing monolithic app into microservices architecture design.

I have seen organisations rushing into developing microservices architecture, not fully understanding the complexity of microservice architecture and failing due to a lack of fundamental domain knowledge needed to build reliable microservices. It is vital to understand the anti-patterns and pitfalls of microservices before you start architecting and developing microservices.

This book addresses challenges and anti-patterns that you will normally face while adopting microservices. If you are new to microservice architecture or even have previous experience, I will highly recommend reading this book before you think about the technical design and implementation of microservices. This book is equally useful for intermediate to advanced users. Ovais along with Nabil and Timothy have authored this superb book that can steer you in the right direction from day one when it comes to designing and developing microservices.

This book talks about the philosophy of microservices design principles that are essential and explains how you can build teams that will deliver value faster to your customers. It also talks about challenges that you will face when adopting microservice architecture as well as vital components needed when it comes to microservices design.

Often microservice fails due to poor leadership, which this book addresses very well. Understanding domain driven design (DDD) is essential while design microservices architecture, what I like is that there is a whole chapter that addresses this area. This book intuitively addresses the architecture pitfalls and how not to over architect microservices.

This also prepares you for the fundamentals of re-platforming apps and talk about old techniques. The book addresses data design challenges, embracing polyglot persistence, denormalization and explains CQRS. Also helps you understand transaction handling, managing consistency, concurrency, and reporting.

Communication is one of the greatest challenges when it comes to microservices design, this book talks about the fundamentals of microservices communication, and event design pitfalls, API gateways and request timeout handling patterns, all vital components needed for reliable communication. Book also talk about serious concerns relating to security, resiliency, idempotency and monitoring.

Finally, when it comes to deployment, this book guides you on deployment strategy, IaC and modern DevOps principles. Also helps you set up the best test strategy suited for your needs as well as shifting left your testing, unit tests, end to end testing and load testing.

I will highly recommend anyone embracing microservice architecture to read this book to have the essential knowledge needed for a solid foundation of your microservice architecture design.

Embracing Microservices Design: A practical guide to revealing anti-patterns and architectural pitfalls to avoid microservices fallacies Paperback on Amazon

#microservices #embracingmicroservices #microservicesarchitecture  #microservicesantipattern

Wednesday, August 25, 2021

Load balancing - help me choose (Preview) - Diagram

 Microsoft Azure provide various load balancing services such as Azure Front Door, Traffic Manager, Application Gateway, Azure Load Balancer.

For you to decide what is the best service for you depending on your scenario can be quite difficult, if you are not aware how each service work. Therefore we have created little wizard in Azure (i.e. Load balancing - help me choose) that will help you to pick the right service. This wizard ask you bunch of simple questions and determine what is best solution for you. You can use the Azure Load Balancing page in the Azure portal to help you guide to the right load-balancing solution for your business need.

I have created following decision flow diagram that is based on the very same wizard flow in Azure portal. You can visually see all options at the same time. I hope this would be helpful for you, you can even print it and have it handy when needed :)

Wednesday, June 2, 2021

Structured review of Azure architectures: A guide for web application review

 Invest a lot of effort to create a perfect architecture before construction should be avoided because this is unrealistic in software development. It is recommend investing in a little bit of architecture envisioning early to identify architecture options in high level, but details should emerge over time. Development team should ensure that architecture will be validated through functioning software, and will be reviewed frequently throughout the project to support optimal implementation. Moreover, emergent architecture should influence and correct intentional architecture.

Architecture review should be performed through out the project development. If you have web app work load in Azure or if you are thinking to move it to Azure, its recommend to perform structured architecture review on following key areas:

  • Availability
  • Scalability
  • Resiliency
  • DevOps
  • Security
  • Management Tools

Performing an Azure architecture review is no longer an activity limited to experts. This paper, by Mahesh Kshirsagar of the AzureCAT team, identifies review drivers and explains how to evaluate your current architecture against these drivers to detect and address current risks. Project teams of any size can self-start a review with this resource. Click download button below to get free PDF copy.

Ref: Microsoft Docs.

Tuesday, June 1, 2021

Choosing Compute Services on Azure (AKS, Service Fabric, App Service)

If you are planning to move your services to cloud its important to understand what is the best candidate compute service for you. You don't want to over/under  provision your solution. So what is the best service we should pick, this is on of the question that i am asked often. While there is no single right or wrong answer it depends on what kind of workload and SLAs you have that will dictate what is best compute service for you.

Azure Compute Services offer following key workloads:

  • App Service: A managed service for hosting web apps, mobile app back ends, RESTful APIs, or automated business processes.
  • Azure Kubernetes Service (AKS):  A managed Kubernetes service for running containerized applications.
  • Batch : A managed service for running large-scale parallel and high-performance computing (HPC) applications 
  • Container Instances: The fastest and simplest way to run a container in Azure, without having to provision any virtual machines and without having to adopt a higher-level service. 
  • Functions: A managed FaaS service. 
  • Service Fabric: A distributed systems platform that can run in many environments, including Azure or on premises. 
  • Virtual machines: Deploy and manage VMs inside an Azure virtual network.

It is also important to understand following hosting models:
  • Infrastructure-as-a-Service (IaaS) lets you provision individual VMs along with the associated networking and storage components. Then you deploy whatever software and applications you want onto those VMs. This model is the closest to a traditional on-premises environment, except that Microsoft manages the infrastructure. You still manage the individual VMs. 
  • Platform-as-a-Service (PaaS) provides a managed hosting environment, where you can deploy your application without needing to manage VMs or networking resources. Azure App Service is a PaaS service. 
  • Functions-as-a-Service (FaaS) goes even further in removing the need to worry about the hosting environment. In a FaaS model, you simply deploy your code and the service automatically runs it. Azure Functions is a FaaS service

 Following chart show how best to pick candidate compute service for you:

You also need to look at aspects such as scalability, availability, security and how easily you can perform DevOps.

Ref: Microsoft Docs.

Friday, May 28, 2021

What is Bicep

Have you been writing ARM templates and didn't quite fancy the way ARM templates are written in JSON. Well Bicep is here that would help you author ARM templates with much cleaner syntax. Bicep give you abstraction the way ARM templates are now written. Its supported by Microsoft 100% free, very modular, state is stored in Azure no manual handling. 

You can get latest windows installer here or see all install options here: bicep/ at main · Azure/bicep (

You can also download Bicep Visual Studio Code extension.

Hello world sample Bicep file to spin up storage in Azure..

param location string = 'eastus'

param storageAccountName string = 'azmubistorageacc1' // must be globally unique

var storageSku = 'Standard_LRS' // declare variable and assign value

resource stg 'Microsoft.Storage/storageAccounts@2019-06-01' = {
  name: storageAccountName
  location: location
  kind: 'Storage'
  sku: {
    name: storageSku // reference variable

output storageId string = // output resourceId of storage account

Edit it in VS Code using Bicep extensions.

Deploy template using Bicep CLI (make sure to create resource group in Azure in advance e.g. bicep).

az deployment group create -f ./test.bicep -g bicep

Storage account created in Azure using Bicep.

Bicep Language specifications can be found here.

Bicep Azure DevOps Task is available here.

- task: BicepBuild@0
    process: 'single'
    sourceFile: '.\bicep_files\sample1.bicep'
    stdout: false # Note if stdout is true 'outputDirectory' will not be interpreted
    outputFile: '.\bicep_files\sample1.out.json' # Only when 'stdout' is false or not defined and 'outputDirectory' is empty or not defined

Bicep Build Actions (Github Action) is available to run the Bicep CLI to build ARM template more.

# Runs the bicep CLI action - individual files
- name: Run Bicep build
  uses: aliencube/bicep-build-actions@v0.3
    files: sample1.bicep sample2.bicep biceps/sample3.bicep biceps/sample4.bicep

# Checks the result
- name: Check the result
  shell: bash
  run: |
    shopt -s globstar
    ls -altR **/sample*.*

If you have existing ARM templates you can decompile them.

bicep decompile "path/to/MyARMTempateFile.json"

You can also export your Azure resource group to .bicep file.

step 1 - az group export --name "MY-Azure-Resource-Group" > MainARMTemplate.json
step 2 - bicep decompile MainARMTemplate.json

Learn more about Bicep here ..

Sunday, January 3, 2021

Azure Traffic Manager vs App Gateway vs Front Door vs Load Balancer


Some of the key features and difference between Azure Traffic Manager, App Gateway, Front Door and Load Balancer.

Traffic Routing methods.

Traffic Manager:
  • Priority (default and backup endpoints)
  • Weighted (distribute across endpoints)
  • Performance (nearest endpoint)
  • Geographic (geography controlled for GDPR etc)
  • Subnet (endpoints base don IP)
  • Multi-value (multiple ends available)

Front Door:
  • Latency (least latency endpoint)
  • Priority (primary then secondary)
  • Weighted (based on endpoint weight)
  • Session Affinity (same endpoint per session)

Application Gateway:
  • Multiple site hosting
  • URL routing
  • Redirection
  • Rewrite HTTP headers and URL

Decision Tree:

Reference Architecture Examples:

The following table lists various architecture reference articles based on the load-balancing services used as a solution.

Load BalancerLoad balance virtual machines (VMs) across availability zonesLoad balance VMs across availability zones helps to protect your apps and data from an unlikely failure or loss of an entire datacenter. With zone-redundancy, one or more availability zones can fail and the data path survives as long as one zone in the region remains healthy.
Front DoorSharing location in real time using low-cost serverless Azure servicesUse Azure Front Door to provide higher availability for your applications than deploying to a single region. If a regional outage affects the primary region, you can use Front Door to fail over to the secondary region.
Application GatewayIaaS: Web application with relational databaseLearn how to use resources spread across multiple zones to provide a high availability (HA) architecture for hosting an Infrastructure as a Service (IaaS) web application and SQL Server database.
Traffic ManagerMulti-tier web application built for high availability and disaster recoveryDeploy resilient multi-tier applications built for high availability and disaster recovery. If the primary region becomes unavailable, Traffic Manager fails over to the secondary region.
Azure Front Door + Application GatewayMultitenant SaaS on AzureUse a multi-tenant solution that includes a combination of Front Door and Application Gateway. Front Door helps load balance traffic across regions and Application Gateway routes and load-balances traffic internally in the application to the various services that satisfy client business needs.
Traffic Manager + Load BalancerMulti-region N-tier applicationA multi-region N-tier application that uses Traffic Manager to route incoming requests to a primary region and if that region becomes unavailable, Traffic Manager fails over to the secondary region.
Traffic Manager + Application GatewayMulti-region load balancing with Traffic Manager and Application GatewayLearn how to serve web workloads and deploy resilient multi-tier applications in multiple Azure regions, in order to achieve high availability and a robust disaster recovery infrastructure.