In a Azure App Service Plan, one can have several slots in addition to the production one.
Do they share resources?
For example, do they each share the same CPU resource or have their own?
In other words, can one slot impact another if it consumes too much (including the production slot)?
Where is this officially documented?
Yes, all deployment slots share resources within the App Service Plan.
As per the official docs,
In App Service, an app runs in an App Service plan. An App Service
plan defines a set of compute resources for a web app to run. These
compute resources are analogous to the server farm in conventional web
hosting.
When you create an App Service plan in a certain region (for example,
West Europe), a set of compute resources is created for that plan in
that region. Whatever apps you put into this App Service plan run on
these compute resources as defined by your App Service plan
For answering your question which is mostly depends on the pricing tier which you have chosen
Shared compute: Free and Shared, the two base tiers, runs an app on
the same Azure VM as other App Service apps, including apps of other
customers. These tiers allocate CPU quotas to each app that runs on
the shared resources, and the resources cannot scale out.
Dedicated compute: The Basic, Standard, Premium, and PremiumV2 tiers
run apps on dedicated Azure VMs. Only apps in the same App Service
plan share the same compute resources. The higher the tier, the more
VM instances are available to you for scale-out.
Isolated: This tier runs dedicated Azure VMs on dedicated Azure
Virtual Networks, which provides network isolation on top of compute
isolation to your apps. It provides the maximum scale-out
capabilities.
Consumption: This tier is only available to function apps. It scales
the functions dynamically depending on workload. For more
information, see Azure Functions hosting plans comparison.
For the slot settings as well, it will share all the resources from the App Service Plan
Related
I am curious about the difference is when creating an App Service in the reservations for 3 years and just having an App Service Plan which I can add multiple App Services to ?
The cost is much lower than an App Service Plan, but I was wondering if its the exact same concept as an App Service Plan ?
Meaning I can create multiple App Services and have them all in the same App Service Plan ?
Or is the Reservation App Service for a single app alone ?
Yes, you can deploy multiple App Services in the same App Service Plan though it is normal or reserved.
You can also create multiple App Services within the same region or across regions supported by Azure in which this flexibility makes ASEs ideal for horizontal scaling feature.
Features of Normal ASP and Reserved ASP were almost same, and you'll get some discount on the Reserved ASP cost.
In the Middle of Reserved ASP, you can increase the Number of instances in that ASP based on your requirement or load balancing.
Refer to Azure App Service Pricing doc and How Reservation works in Azure App Service for more information.
I'm writing an API that will basically provide services to read and write to a Database.
My goal would be to have three environment. Dev, Stage and Production.
The first idea was to have three different resource groups, each with three different App Service Plans to host each environment.
Then i started reading and the recommended strategy seems to be to have all of the environments hosted within one App Service Plan. This way you could take advantage of swapping deployment slots. Also I'd be paying one third of the price.
But i also read that it's good to have a production environment isolated from the rest. So this way I'd need one App Service Plan for Prod, and another one for the rest of my environments.
So my first question is, is there a suggested/standard way to proceed setting up environments?
Is swapping exclusive to environments within a single App Service Plan?
Also i was comparing specs of Standard, Premium and Isolated tiers, and i couldn't find info on if Isolated App Services Plan have 'Staging Slots' for deployment. I know that Standard tier comes with 5 slots and Premium tier has 20. Does Isolated App Service Plans not support multiple deployment slots?
Thanks in advance for any insight that you guys can provide me.
is there a suggested/standard way to proceed setting up environments?
As far as I know, it is convenient for us to create deployment slot in the azure portal when the app is running in the Standard or Premium App Service plan tier.
Add a deployment slot
In the azure portal, open your app's resource blade-->Deployment slots-->Add Slot-->give the slot a name and select Configuration Source. If you have several slots, you could swap them manually or set the Auto Swap.
Configuration for deployment slots
When you using the swap feature, you should know the settings that can be swapped or not. Also, you could set slot setting, note that marking a configuration element as slot specific has the effect of establishing that element as not swappable across all the deployment slots associated with the app.
For more details, you could refer to this article.
Is swapping exclusive to environments within a single App Service Plan?
Per my understanding, App Service Plan is like a VM, it holds your app, deployment slot is like a copy of the web app that you can make different configurations. It also be held with the App Service Plan. If the App Service Plans have different pricing tier, they will have different features. So we could not swap the slots in different Service Plans.
Does Isolated App Service Plans not support multiple deployment slots?
Actually, Isolated App Service Plan supports deployment slots.You could view full details for App Service Plans.The Isolated tier is special.In the Isolated tier, the App Service Environment defines the number of isolated workers that run your apps, and each worker is charged hourly. In addition, there's an hourly base fee for the running the App Service Environment itself.
You could select the tier when creating the App Service Plan, but cannot scale up to this tier in the scale up option in the resource blade.
I am trying to wrap my head around the concept of Azure App Service plan and Azure App Services, with no luck.
My understanding is that an App Service Plan defines the capacity and the pricing, all apps assigned to a specific App Service plan will share the same resources, is that right?
If that is right, then what is the benefit of the scaling-out? If the scale out will create more instances of the same app which at the end will be hosted on the same App Service Plan (sharing the same resources)?
I read almost all the official and non-official documentation about Azure App Service plan and App Services but couldn't find an answer to this question, they are all saying that scaling is working on the app level (not the app service plan) and at the same time saying that the apps assigned to the same app service plan are actually sharing the same resources, so what is the benefit of the scale-out feature?
Regards,
My understanding is that an App Service Plan defines the capacity and
the pricing, all apps assigned to a specific App Service plan will
share the same resources, is that right?
Yes.
If that is right, then what is the benefit of the scaling-out? If the
scale out will create more instances of the same app which at the end
will be hosted on the same App Service Plan (sharing the same
resources)?
No one forces you to put all your apps on the same App Service Plan. When you create an App you put it into some App Service Plan. All the Apps on that (and only that) App Service Plan would share resources, but you could create a lot of App Service Plans.
Also, when you scale out you create more PaaS instances of the VM's hosting your App, so when you scale out you are not getting another App Pool in the same IIS, you are getting another App Pool on the other IIS on the other VM.
edit: to clarify the comment, the App Service Plan is a collection of Windows VM's with IIS installed on them. All the Apps assigned to that App Service Plan are hosted on ALL the instances of those VM's, when you scale out or scale up you change the number or capacity of those VM's.
There's no temporary App Service Plan. You pay for the Service Plan, not for the App. Apps cost nothing, they are simply consuming resources on the Service Plan, its the Service Plan that "eats" money. You are getting billed according to the Service Plan tier and scale.
Pricing is based on the size and number of VM instances you run.
As I know, the scale out would create multiple copies of your web app and add a Load Balance to distribute the requests between them automatically. And you don't need to configure the load balance separately by yourself.
Assuming that you create a website (a windows server with IIS), then your website would has the App Pool which defines the available resources for your website. Each instance could handle a limited number of requests, in order to reduce the response time, you could scale out your website into multiple instances, then each web-server could split the work load. For more details, you could refer to Scaling Up and Scaling Out in Windows Azure Web Sites and this tutorial for a better understanding of Azure Web App auto scale.
As #4c74356b41 said when you scale out you are going to get more physical resources (i.e VM's with more compute, memory and storage). Also one correction as per Azure documentation, scale out is going to effect all apps in app service plan. see below link and the point to note is
"The scale settings take only seconds to apply and affect all apps in your App Service plan. They do not require you to change your code or redeploy your application" -
https://azure.microsoft.com/en-us/documentation/articles/web-sites-scale/
The docs answer this clearly: https://learn.microsoft.com/en-us/azure/app-service/overview-hosting-plans#how-does-my-app-run-and-scale
In this way, the App Service plan is the scale unit of the App Service apps. If the plan is configured to run five VM instances, then all apps in the plan run on all five instances. If the plan is configured for autoscaling, then all apps in the plan are scaled out together based on the autoscale settings.
I have an Azure App Service Plan on the S3 tier which runs many websites. The service plan is spread across 3 instances. Occasionally I'm seeing periods of high CPU usage for the service plan coupled with general sluggish performance for all websites.
Is there a way (ideally through the portal) to see which website is consuming these resources without going into each of the individual sites? Similar to how a SQL Azure Elastic Pool shows which databases are consuming resources.
As I know, we could not find the web app CPU usage of each site in Azure App Service Plan. All apps related to a Azure App Service Plan share the same resource, it only gives Azure App Service plan CPU usage in Azure portal. At currently, I am afraid you need to go into each of the sites to find out which use the most.
Azure: Pricing of deployment slots for an Azure App Service.
Using an S1 App Service Plan, my web site has up to 5 slots for web app staging.
How are those slots charged? Are they billed only if used? Included in the S1 fee? or something else.
Michael, it part of the app service plan itself. You will see for example that for Azure App Services that standard and premium instances include staging slots. Standard has 5 and premium has 20. They are not priced separate from the plan.
https://azure.microsoft.com/en-us/pricing/details/app-service/plans/
The staging slots are included as part of your App Service tier. A used slot does not cause extra charges as far as the App Service pricing goes. But since they are part of a shared resource, usage on a staging slot can effect the overall performance of the VM. However, a staged site may incur other costs on Azure. If the running of that slot consumes blob data storage, send queue messages, etc. then those costs will still have to be paid as part of the overall application framework.
Should be pay per usage. Azure App Service is charged base on the plan that you are on, all your slots and main site are on the same VM which will cause usage of compute hour.
https://azure.microsoft.com/en-us/pricing/details/app-service/