Microservices in Azure

Question

I understand that Microservices is about independent loosely coupled services. I have read https://en.wikipedia.org/wiki/Microservices.

When it comes to Azure, I understand there are many components like Azure Service Fabric, AKS and also have the option of deploying containers within Azure VMs using Docker or any other containerization tools. However, since Microservices is about developing atmoic individually scalable services, can this also be achieved by deploying each service as an Azure Web API APP within an App Service Plan and configure Auto-Scale based on Performance metrics (though each API APP may not be individually scalable, they can still be individually manageable in terms of deployment, configuration etc)?

Can someone please suggest if this thought process is correct?

Answer 1

Microservices aren't a platform or technology so if you can make small independently deployable services then they are microservices. Sure - some tech helps but it depends on your situation.

If you only need a few services you probably don't need anything complex. Make sure services are well modeled, own their own data and ideally have a good monitoring and deployment pipeline setup. Design for service failure where possible.

Do you need to scale each part independently? Ideally, you should be able to but do services have very different requirements? You could have many small App service plans but that comes at cost of unused resources so split when you need to.

Answer 2

This question and of course the answers are going to be opinion based, but generally when thinking in terms of micros services, think not in terms as things like loads of API's and VM's etc. Instead think in terms of. When i upload an image, its needs to be resized, and the table updated to give a url for the thumb. or when XXX record is updated in database, Run XXX in order to create a report, or update Azure search. and that each service, just knows how to do a single thing only. I.E Resize an image.

Now one could say. I have a system, A repo library, and some functions library. When an image is posted, I upload, then call this, and that etc.

With Micor services. You would instead just add the image to a queue. Create an azure function that has a queue trigger. that would resize and save both the large and the thumb to storage. this would then either update the database, or in true micro service, it would add a queue to store the new info, another function would watch that queue and insert into the database.

You can use the DB queue from anything. You can use the Blob queue from anything. Your main API, does not care how images are handled. You can change your functions one day to maybe save to dropbox, instead of azure blob. All really easy, with no re-build of the API, because the API does not care.

A good example I use it for is email and SMS. My systems dont know how to send an email, or an SMS. They only know how to add to a queue. My microservices. SendEmail and SendSMS do know how to do it, and I can change how and who i send that content with, really easy. I can tomorrow change from Twilio to send grid, without ever telling the API that i've done it.

On a more complex thing. I have approval, at the moment that approval sends an email or SMS to either user or admin, and that can change over time. So I have an SMS server, Email Service and and approvalService. when approval happens, it just adds a config to the queue, The rest is done by a logic app, that knows to send an email to XXX and an SMS to XXX and then update database. My api, is just a post, that creates a queue.

Basically what I am saying here is to get started, maybe porting an existing app. Start with the workflow stuff, like send an email, resize an image, create a report, create a PDF, email 50 subscribers etc. and take all that code out and put into there own micro service that just knows how to do one thing. Then when you grow with confidence, create a workflow from all of these services with Logic Apps, let azure take care of the rest, thats what they want to do.