Azure API Management Scalability - azure

Azure API Management has promises of 1000 requests per second for an instance. (I don't know this is a correct rate but let's assume it is). My question is how can we scale web service without scaling its infrastructure just by scaling API Management instance.
For example if Azure API Management supports 1000 requests per second for an instance, then backend service also should support the same request handling threshold in its infrastructure. If this is the case what is really meant by scaling up the web service by Azure API Management.

By using Azure API management you can turn on caching easily, which can significantly reduce the traffic to your back-end. In addition, your API Management instance can be scaled up easily to have more VMs behind it. However, if the back-end cannot handle the traffic (after caching), then you might need a more scalable back-end :)

Miao is correct. However remember Azure API Management scaling will only work with GET request. Plus cache size provided by API Management is of only 1GBas of today [may increase in future]; with no monitoring as of today. So if you need monitoring of API Management cache then use external cache like Redis.
When you talk about scalability it will be at all layers. API Management consumption plan can be good option to think through for auto scaling. Then think of Azure VMSS or App service auto scale for scaling backed APIs. And if your backend APIS are talking to DB then think of something like Autoscale for DB on Azure like SQL Azure HyperScale.
So scalability is not only at API Management level but think carefully at all layers.
Sample implementation of Cache in API Management is here - https://sanganakauthority.blogspot.com/2019/09/improve-azure-api-management.html

Related

Azure App Service Plan: Function vs App Service?

When hosting an Azure Function in an App Service Plan, are there any significant differences compared with using an App Service (EDIT: for a restful API) associated with the same App Service Plan? I assume the only difference is that the Function offers additional out of the box triggers. Any differences I'm missing that would lead to preferring one over the other?
I'd also like to confirm that hosting Azure Functions in an App Service Plan can actually limit scalability if scaling is not configured on the App Service Plan. As I understand it, Functions automatically scale as needed when using Consumption or Premium hosting without additional configuration.
When hosting an Azure Function in an App Service Plan, are there any significant differences compared with using an App Service associated with the same App Service Plan? I assume the only difference is that the Function offers additional out of the box triggers. Any differences I'm missing that would lead to preferring one over the other?
Well, an Azure Function is a different beast than an App Service. An Azure function is triggered by an external event or a timer. It then executes the code of the function. When hosted on a consumption plan this execution is allowed to run for 5 or 10 minutes max. When you need a longer execution time you need to run it on an App Service Plan.
An App Service can host any app you've created. Like a website (that runs continuously and doesn't need to be triggered before it starts doing something) or an api for example.
I'd also like to confirm that hosting Azure Functions in an App Service Plan can actually limit scalability if scaling is not configured on the App Service Plan. As I understand it, Functions automatically scale as needed when using Consumption or Premium hosting without additional configuration.
Correct, when hosting Azure Functions in an App Service Plan you are responsible for making sure the app service is scaled to allow the function to perform well under load. Thats why the consumption plan is designed to handle this so the developer can focus on the functionality and does not need to worry about the infrastructure.
So, for integration scenario's azure functions are a very natural fit. For web sites an App Service might be the best solution.
To address your comment:
I should have mentioned that this question was in the context of hosting a restful API and not a UI application. In this scenario, I'm not seeing much difference between a Function and App Service, but please correct me if I'm missing something
A couple of things: For one, there is a certain sweet spot. If traffic is heavy enough a consumption plan based azure function might be more costly than having a dedicated app service plan. That depends of course on a lot of factors (CPU usage, request duration etc.). Also, you won't be able to use things like Asp.Net Core Middleware out of the box.
Finally, I'd argue that if your api is becoming large enough managing a single asp.net core solution may be easier than having to manage a lot of azure functions with small functions or one azure function project with lots and lots of functions, but hey, that's just my opinion (haven't actually dealt with it to be honest)
Some resources to consider:
https://www.taztopia.com/single-post/2019/07/28/azure-function-vs-web-app-aka-serverless-vs-paas
https://dasith.me/2018/01/20/using-azure-functions-httptrigger-as-web-api/
The main difference is in how you pay for it:
Azure Functions Consumption plan you pay per execution
Azure Functions in an App Service (dedicated plan) you pay for the allocated hardware per minute.
You also have control of which VNET your functions run in when you use an app service plan. You may have security requirements that make this important.
You are correct that if you run it in an app service that is not configured to scale, then throughput will be limited by the allocated hardware.
For details see: https://learn.microsoft.com/en-us/azure/azure-functions/functions-scale
If you are having limited and predictable workload then deploy az function in AppService plan with supports VNET integration for private compute otherwise go for Premium plan which will provide autoscaling capability of your compute environment.

What Azure hosting would automatically scale a .NET Core Web API service?

I am building an ASP.NET Web API service that receives orders from restaurants.
At certain times it will be busy, thousands of times more busy than at other times.
I haven't begun developing this yet but I was wondering what Azure services are appropriate to host the service such that it automatically scales when necessary without me worrying about its performance and hosting costs are minimised?
You can create Azure Functions to handle this and auto scale or use an Azure App Service and set it up to auto scale.
Azure functions can be setup to be triggered on HTTP events. These can be configured to scale to multiple instances to handle heavier load. You will need multiple Azure Functions to handle multiple API endpoints.
An azure app service will be will have an app service plan which can be configured to scale horizontally or vertically when the traffic load increases. An app service will be more like a traditional api instead of a small piece of an API like an Azure Function.

Multi tenancy website hosting for legacy monolith web app in Azure

We had a legacy monolith website application that is hosted on Azure windows server and had 10 customers using it, now as the application data grows the bandwidth of the application is affecting each customer because they were hosted in single server as a single website. Now the client wants to split the database as per customer separately to reduce the database load, so we divided the databases as per customer.
Regarding the website, we still had a dilemma on how to proceed, so we already divide the databases so we are thinking as
it is better to host each customer website on separate servers?
create a different website on a single server for each and every customer?.
Because the clients want this to be scalable and 100%, that one client’s activities and usage will not affect another, as well as be able to easily distinguish cost.
The client also asked to differentiate how much cost occurring for each customer on the resource groups,
previously we had a shared resource group.
Could anyone suggest how to solve this problem?
If your requirement fits you could leverage Azure App Service WebApps (PAAS solution).
You can host apps in the same App Service Plan or isolate your app into new App Service plan (as per your requirement) by having tradeoff between level-of control and costs.
Or to have greater control on the underlying VMs you could leverage Azure VMs (IAAS solution).
To start with, kindly take a look at this approach - Common web application architectures – monolithic application design using Azure App Service.
You could create the web application as separate App Service apps. This design lets you run them in separate App Service plans so they can be scaled independently. If you don't need that level of scalability initially, you can deploy the apps into the same plan and move them into separate plans later if necessary.
The pricing tier of an App Service plan determines what App Service features you get and how much you pay for the plan.
Azure App Service plan overview
App Service plans pricing
Azure offers a number of ways to host your application code.
Kindly checkout this architecture guide on compute decision choice
Resource Group is a just a container that holds related resources for an Azure solution. The resource group can include all the resources for the solution, or only those resources that you want to manage as a group. It doesn't have direct cost implications, but the resources/services (in this case App Service) under it does.
You may wish to know:
Explore and analyze costs with cost analysis
Prevent unexpected charges with Azure billing and cost management

Azure API Management vs Logic Apps

New to Azure and would like to know what the difference between Azure API Management and Logic Apps is.
Some pros and cons would be nice. Also what the costing for each of these is like.
Thanks
Seems you want to know about Azure API Management and Azure Logic Apps
Well let me help you what that actually are...
Azure API Management
Azure API Management allows organizations to publish APIs more securely, reliably, and at scale. Use API Management to drive API consumption among internal teams, partners, and developers while benefiting from business and log analytics available in the admin portal
Pros are
Consistent and modern API gateways for existing back-end services
Verifies API keys, JWT tokens, certificates, and other credentials
Help you to publish APIs to external, partner, and internal
developers to unlock the potential of their data and services
High availability Responds to requests to perform operations at
least 99.9% of the time.
Analytics, metrics and many more
For further details you could have a look on official docs
Pricing
There are different categories of pricing available based on type and uses. See the below screen shot:
You even can read more details about pricing here
Logic Apps:
Azure Logic Apps is a cloud service that helps you schedule, automate, and orchestrate tasks, business processes, and workflows when you need to integrate apps, data, systems, and services across enterprises or organizations. Logic Apps simplifies how you design and build scalable solutions for app integration, data integration, system integration
Pros are
Maximum automation with hassle free service
Process and route orders across on-premises systems and cloud
services
Can move uploaded files from an SFTP or FTP server to Azure Storage
Help you connect legacy, modern, and cutting-edge systems more
easily and quickly by providing prebuilt APIs as Microsoft-managed
connectors
Pricing
Usually two categories of pricing you may have Consumption pricing model which depends on how much you consume and have to pay as per your consumption.
another one Fixed pricing model. See the screen shot:
You can have a look more details on official docs
Hope this would help you.

Can the server's in-memory cache be used in Azure?

I need my Web API to have caching to store some data. I have been researching caching on Azure and I can see that Microsoft recommends to use Redis cache.
Can I use the normal server's in-memory cache to store simple data which will only be accessed by the Web API or is Redis my only option.
Are there any limitations of server memory on Azure?
Of course, you can. Azure Redis cache is not the only option. You can consider to use Microsoft.Extensions.Caching.Memory like MemoryCache to store your simple data, and make sure the size of your data is less than the available tails memory size on Azure App Service which be restricted by the memory limit of Azure App Services for different tiers, as the figure below from App Service limits.
Meanwhile, even you can consider to implement your Web API by using Azure Functions with HTTP trigger which support more memory, please refer to Functions limits.
Hope it helps.

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