I just came across a new Azure feature - Azure Scheduler:
http://gauravmantri.com/2013/11/10/windows-azure-scheduler-service-part-i-introduction/
I was wondering - from an architectural perspective - how is this any better or different from using an online CRON service to send a predefined request to a WebAPI endpoint? I'll need a WebAPI endpoint in both cases - with the Azure offering, I have the ability to Enqueue into an Azure Queue, but otherwise it's the same thing, right (maybe with the former being cheaper)?
Two big differences with the scheduler service
Managed and paid for within the same Azure subscription. This does make ops a little easier.
The RESTful API for the service.
As good as it may be, it is expensive compared to other offerings in the market (I use setcronjob). As you point out, you still need to write your job endpoint anyway.
Related
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.
How does a Azure function differ from a ASP.NET Core Worker Service?
Does both of these cover the same use cases?
How do I decide which one to use?
Update:
Azure function is designed for azure. So when you use azure, or other azure services which are integrated with azure function, you should consider azure function, which could simplify your code and logic by the built-in features of azure function. But it will also have charges for azure function. And yes, if you don't use azure, just use asp.net core worker services.
Azure function are totally different from ASP.NET Core Worker Service.
The benefit of Azure function is that it supports a lot of triggers like azure blob trigger / azure event hub trigger, and is integrated with other azure services.
With these built-in features, it's easy to create a proper azure function to complete a proper task. For example, if you upload an image to azure blob storage, and then want to resize the image, you can easily create a blob trigger azure function with less code.
Worker services are the perfect use case for any background processing. And if you want to operation some azure services like azure blob / azure event hub etc. you may achieve this but need to do a lot of work.
At last, it depends on your use case to choose which one should be used, and select the simple / efficient one.
I think the answer Fred was looking for is, why would someone use Azure functions over Asp.net Core hosted service? And the answer isn't only because you have Azure account so everything is easy and integrated. It depends. I.e Traffic, cost, expertise, etc.
Actually, there are guidelines set by Microsoft when to use an Azure Functions versus let's say over a IHosted service running in a linux container hosted in AKS for example. and I'll post the link, but it's basically if your workload is mission critical or not. If you want the best performance, lowest cost, reliability a hosted dotnet core service running in Linux container would be an excellent alternative.
Here is the mission critical guidelines from Microsoft, hope this helps!
Design recommendations
Azure Functions:
Consider Azure Functions for simple business process scenarios which don't have the same stringent business requirements as business-critical system flows.
Low-critical scenarios can also be hosted as separate containers within AKS to drive consistency, provided affinity and anti-affinity requirements are fully considered when collocating containers on nodes.
Excerpt taken from here:
https://learn.microsoft.com/en-us/azure/architecture/framework/mission-critical/mission-critical-application-platform
I've recently started experimenting with Azure functions and I'd like to get some info on whether the following makes sense and is possible..
How feasible is it to build a normal .NET Core Web API following DDD patterns but replacing the API endpoints with durable azure functions? Is this a possible use case for Azure Functions, to make the web API "serverless"?
And how would the whole thing be structured? Does each Azure function need its own project or can they all be placed in one project?
Thanks
As I wrote in comments why not?
You can define bounded context and deploy to one azure function as microservice for instance service which will be responsible for orders, other azure function of delivery and so on.
Use durable function when you need to orchestrate actions, for instance you have buy flow when in first action you lock products, take payments and unlock so you have kind of dependency on each other.
You can use azure functions with service bus or azure queue storage for event processing.
One thing keep in mind that when you design function you have time limitations is up to 5 minutes on provisioning plan. So when you design newsletter for instance keep in mind that you would need to send email in batches.
We have a scenario for on prem to upload a bunch of pdf/tiffs then service on the cloud to process them. In the same time a queue is populated with metadata on processing instructions.
We are trying to decide if whether the worker role or the Azure Batch is the right choice for this. Our primary goal are,
need to scalable base on queue size
scale ramp up time need to be quick
of course cost is another factor
You should not use PaaS cloud services for new workloads. There are various options depending on the complexity of the processing you need to do. The following are likely better choices than Azure Batch: Azure Web Jobs, Virtual Machine Scale Sets. The first is easier to use, and is based on the Web Apps technology, while the second is the (preview) way to provide scale-out VMs.
PaaS cloud services are classic now, you can use webjobs with appservices. Another interesting option is AZURE STACK which is really good for hybrid cloud. refer this link
https://azure.microsoft.com/en-us/overview/azure-stack AZURE STACK is really good for hybrid cloud, As if now it is in Technical preview.
We currently have a window service which send some notification emails to users after doing some processing on database(SQL database). Runs once in day.
We want to move this on azure cloud. One alternate is to put it on Azure VM as is. but I am finding some other best possible solution for that.
I study about recurring and on demand Web jobs but I am not sure is this is best solution.
Also is there any possibility to update configuration of service code in App.config without re-deploy the code of service on cloud. I means we can manage configuration from Azure portal.
Thanks in advance.
Update 11/4/2016
Since this was written, there are 2 additional features available in Azure that are both excellent choices depending on what functionality you need:
Azure Functions (which was based on the WebJobs described below): Serverless code that can be trigger/invoked in various ways, and has scaling support.
Azure Service Fabric: Microservice platform, with support for actor model, stateful and stateless services.
You've got 3 basic options:
Windows service running on VM
WebJob
Cloud service
There's a lot of information out there on the tradeoffs between these choices, but here's a brief summary.
VM - Advantages: you can move your service basically as it is without having to change much or any of your code. They also have the easiest connectivity with other resources in Azure (blob storage, virtual networks, etc). The disadvantage is you're giving up all the of PaaS advantages and are still stuck managing your own VM infrastructure
WebJob - Advantages: Multiple invocation options (queues, blobs, manually, queue receive loops, continuous while-loop style, etc), scheduled (would cover your case). Easy to deploy (can go with website, as a console app, automatically through Kudu), has some built in logging in Azure portal - and yes, to answer your question, you can alter the configuration in the portal itself for connection strings and app settings.
Disadvantages - you'll need to update code, you don't have access to underlying resources (if you need that), and more of something to keep in mind than a disadvantage - it uses the same resources as the webapp it's deployed with.
Web Jobs are the newest of the options, but at the same time appear to have active development going on to increase the functionality and usefulness.
Cloud Service - like a managed VM, has some deployment options, access to underlying VM if needed. Would require some code changes from your existing service.
There's nothing you've mentioned in your use case that makes me think a Web Job shouldn't be first thing you try.
(Edit: Troy Hunt has a great and relatively recent blog post illustrating most of the points I've mentioned about Web Jobs above: http://www.troyhunt.com/2015/01/azure-webjobs-are-awesome-and-you.html)