We have written a high scalable Cloudservice for MS Azure with two roles: "WebsiteRole" and "WebsiteWorkerRole". For better performance we deploy this Cloudservice in multiple regions (2x US, 2x EU, 1x JP). We have different configuration files for each region (EuWestProductive.azurePubxml, ServiceConfiguration.CloudEuWest.cscfg, Web.ReleaseEuWest.config).
Now the Problem: In each Region we have running the "WebsiteRole" and "WebsiteWorkerRole". But the "WebsiteWorkerRole" has only very small tasks, so that one extra small instance in one region is more than enough.
We tried to set the Role instance count to zero (ServiceConfiguration.CloudEuWest.cscfg). But this is not allowed:
Azure Feedback: Allow a Role instance count of 0
Is there an other way to remove a role when deploy the Cloudservice?
No, as you've discovered, a cloud service does not allow for scale to zero. You have to effectively remove the deployment. To have the minimum change to what you already have in place you could separate the two roles into two different deployments. Then have an Azure Automation Script, or set of scripts run elsewhere, that handles deploying the worker role when needed and decommissioning when it's not needed.
Depending on the type of workload that worker is doing you could also look at taking another route of using something like Azure Automation to perform the work. This is especially true if it's a small amount of processing that occurs only a few times a day. You're charged by the minute for the automation script, so just make sure it's going to run less than the actual current instance does.
It really boils down to what that worker is doing, how much processing it really needs to do, how much resources it needs and how often it needs to be running. There are a lot of options, such as Azure Automation, another thread on the web role, a separate cloud service deployment, etc. Each with their own pros and cons. One option might even to look at the new Azure Functions they just announced (in preview and charged by the execution).
The short answer is separate the worker from the WebSiteRole deployment, then decide the best hosting mechanism for that worker role making sure that the option includes the ability to only run when you need it to.
Thanks #MikeWo, your idea to separate the deployments was great!
I have verified this with an small example project and it works just fine. Now it is also possible to change the VM size and other configurations per region.
(Comments do not allow images)
Related
As I understand there is no concept of update domain in App Services (and in other PaaS offerings). I am wondering how Azure is handling OS updates if I have only a single instance of an App Service app. Do I need to plan for two and more instances if I want to avoid such cases when an app goes down during the OS/other updates or this is handled without downtime? According to docs App Service has 99.95% SLA - is this time reserved here?
First of all, welcome to the community.
Your application will not become unavailable when App Services is patching the OS, you don't have to worry about that. Imagine if that would be the case, it would be a huge problem. Instead, the PaaS service will make sure your application is replicated to an updated worker node before that happens.
But you should have multiple instances, as a best practice listed in this article:
To avoid a single point-of-failure, run your app with at least 2-3 instances.
Running more than one instance ensures that your application is available when App Service moves or upgrades the underlying VM instances
Have a look at this detailed blog post:
https://azure.github.io/AppService/2018/01/18/Demystifying-the-magic-behind-App-Service-OS-updates.html
When the update reaches a specific region, we update available instances without apps on them, then move the apps to the updated instances, then update the offloaded instances.
The SLA is the same regardless the number of instances, even if you select "1 instance":
We guarantee that Apps running in a customer subscription will be available 99.95% of the time
Have a look at Hyper-V and VMWare, it will give you a rough idea on how App Services handle that.
If you're looking for zero-downtime deployments with App Services, what you are looking for are deployment slots.
Managing versions can be confusing, take a look at this issue I opened, it gives you a detailed how-to approach about managing different slot versions, which is not clearly described by Microsoft docs.
I thought one of the advantages of Azure was that I could turn services on and off depending on when I want them to be available.
However I cant see how to pause my App Service Plan.
Is it possible?
I want to use the S1 tier so that I can play with what it offers. However I want to be able to pause the cost accumulation when I am not using it.
I see from the app service pricing help that an app will still be billed for even though it is in the stopped state.
Yet the link also clearly states that I only pay for what I use. So how does that work?
If you put your hosting plan onto the free tier, you will stop being charged for it. However if you have things like deployment slots and certificates these will be deleted.
The ability to turn services on and off, is more to do with being able to scale services, so if you need 50 servers for an hour you can easily do that.
What you can do to make your solution temporary is to create a deployment script, using Powershell or Resource manager Templates then you can deploy your solution for exactly as long as you need it and then delete it again when you don't. In this sense you can turn your services on and off at a whim.
Azure provides building blocks for you to create the solution you need, it is up to you to figure out how to best use those building blocks to create the solution you seek.
Edited to answer extended question.
If you want to use the S1 pricing plan, and not have it charge when you are not using it, the only way of achieving that is by using automation. Fortunately, this is reasonably trivial to achieve.
If you look at this template it is pretty much all configured to deploy a website from Github to Azure on demand. If you edit that to configure it to your needs you can have a new Azure website online with 2 minutes of running the script.
Then you would have another script that deleted it once you had finished.
Doing it this way you would loose no functionality, and probably learn quite a bit about what is possible with Azure along the way.
App Service Plan
An app service plan is the hardware that a web app runs on. In the free and shared tier your web apps share an instance with other web apps. In the other tiers you have a dedicated virtual machine. It is this virtual machine that you pay for. In that case it is irrelevant whether or not you have web apps running on your app service or not, you still have a virtual machine running and you will be charged for that.
To change the App Service Plan via PowerShell, you can run the following command
Set-AzureRmAppServicePlan -ResourceGroupName $rg -Name $AppServicePlan -Tier Free
I was able to accomplish this using the dashboard by selecting the App Service Plan, clicking Scale up (App Service Plan), and then from there if you click Dev/Test you can select the Free tier.
As others have mentioned, you need to script this. Fortunately, I created a repository with one-click deployment to your Azure resources.
https://github.com/jraps20/jrap-AzureVerticalScaling
The steps are intended to be as simple and generic as possible:
Execute the one-click deployment from the repo readme
Select the subscription, resource group etc.
Deploy resource to Azure
Set up your schedule to scale up and scale down as-needed
The scripting relies on runbooks and variables to maintain the previous state of each App Service Plan and App Services within those plans. Some App Services cannot be scaled due to specific settings being used (AlwaysOn, Use32BitWOrkerProcess, ClientCertEnabled, etc.). In those cases, the previous values are stored as variables prior to down scaling and then the original values are reapplied when the services are scaled up.
For more clarity, I have written a blog post that goes into detail. The post is pertaining to Sitecore, but applies to any App Service setup- Drastically Reduce Azure PaaS Hosting Costs in Non-Prod Environments With Scheduled Vertical Scaling. It also includes a brief video tutorial to show its use case.
Myself and others have been using this repository/approach for well over a year and it works great. I mostly use it for POC's to reduce costs when I'm not actively working on something. However, its main intention was for targeting non-prod environments to save costs during non-work hours.
Azure App Service Plan is just an logical concept of a set of features and capacity that you can share across multiple apps. I don`t think you can "pause" a plan, instead you can pause your service. and depends on billing model of each service, you might or might not get charged.
Pausing = Delete or lower tier.
Scripting is the key.
Design Diagram
Use scripts to create (also consider shared resources)
Delete using scripts
Use scripts to recreate.
eg: If we use resource group properly per environment then
Export-AzureRmResourceGroup will create a template for us (everything in the resource group will be pulled out as script). So we can delete it and recreate it anytime.
To pause a VM and stop billing you need to shut is down and deallocate it. Just shutting down still has the capacity reserved as if its running.
Storage can't be shutdown - it can be moved to lower cost tiers.
I have few services which has very low usage, but they are quite hardware intensive when they are used. Right now they run separately. Every of them has its own Web Role and Worker Roles. Every of this roles run on its own VM with specified size and instances count. That is I believe standard way.
I would like to rent one quite powerful VM from Azure, on which I would like to deploy every of my services. Ideally without changing structure of code so I can keep them in separate projects/solutions. They will run simultaneously and all of them will be accessible.
You cannot deploy more than one cloud service package to a set of role instance vm's. If you want all of your services to run in a single role instance (or set of instances), you need to bundle all of your services into that role. How you do that, and how you organize your code, is strictly up to you.
Iam relatively new to Cloud Computing and azure. I was wondering whether you can have more than one web and worker role in an Azure application. If so what advantages can I get using multiple roles and where do they apply?
Yes, you can have more than 1 web or worker role in an Azure Cloud Service. You can have up to 25 different roles per deployment I believe in any mix of Web and Worker roles. See the Azure Subscription and Service Limits, Quotas and Constraints link for more information.
The advantage of having the roles within the same cloud service is simply that within that cloud service they can see all the other roles and instances easily (unless you configure them otherwise). They will all be relatively close to each other within a data center because a cloud service is assigned to a stamp of machines and controlled by a Fabric Controller assigned to that stamp. You can watch this video by Mark Russinovich which sheds more light on the inner workings of Azure and talks a bit about stamps I think. A cloud service is a security boundary as well, so you get some benefits from that encapsulation if you need to do a lot of inter machine communication that ISN'T going across a queue for some reason.
The disadvantage of batching a whole bunch of roles together is that they are tied pretty closely together at that point. You can certainly scale them separately, and you can do updates that target only a single role at a time. However, if you want to deploy changes to multiple roles you may end up having to do a full deployment to all roles (even those that haven't changed) or do updates to single roles one at a time until all the ones you need updated are, which can take some time. Of course, it could be argued that having them in separate cloud services would still have you doing updates concurrently depending on your architecture and/or dependencies.
My suggestion is to group only roles that REALLY belong together in the same solution. These are role that have workloads that are interrelated. Even then, there's nothing stopping you from separating these as well into separate deployments (though you may benefit from the security boundaries that being within the same cloud service). Think about how each role will be updated, and if they would generally be updated together or not. There are many factors in thinking about how to package roles together.
I was hoping I'd be able to find Azure billing 'use cases' somewhere on the MS site or on StackOverflow.
Maybe I'm being paranoid but I'm trying to be certain before I tell a customer that it'll cost $XXX.00 to move his app to Azure.
I've got an MVC site running on a server in his office. It's a data-based app using SQL-Server. Data intensive but just about 20-30 users. The purpose of going to "The Cloud" is not scalability but reliability.
Lets just say I need a Cloud Service with 2 medium VMs (2 so that we have fail-over capability) and a 1GB SQL Database. Say $2 worth of Bandwidth (15 gb) would probably be enough. Geo Redundant Storage: all the stuff besides the DB is comprised of Code. Very little in the way of resources, total less than 20 megs.
So, my question: By running a Web and Worker am I using two instances? One for Web and one for Worker? If so, can I run the app in just a Web Role? I don't run a separate service. What if I did run both Web and Worker roles for the same site, would that be an extra instance (4 instances instead of 2)?
So, by running a Web and/or Worker role am I ALSO incuring a Virtual Machine instance? If not, does the scenario change if I occasionally RDP into the Web/Worker instance?
Thanks for any insight into this. Also, does anyone know of a MS site that has billing 'use cases' like this?
Based on your description, I'm not sure why you'd want a Worker role. Worker roles are ideal for handling transactions, processing, etc. but I'm not sure if you need that. For example, worker roles can process submitted orders, resize images, etc. Basically any process that you'd like to abstract from the user interface.
Since you mention that you want fail-over capability, you should probably use at least two of whatever role(s) you choose. For example you will need a Web role for your MVC web site. You'll need two instances of whatever size you choose to qualify for Microsoft's Cloud Services SLA uptime guarantee of 99.5%.
Should you decide you need a Worker role, you'd need two instances of that as well.
It's not required to use a minimum of two instances per role type, but it's certainly recommended for production apps, and is required for SLA coverage.
you get charged for each role you activate, so web and worker role will be separate. as far as combining the worker and web together, not sure progrmatically how the
Ok lets take this one by one.
By running a Web Role and a Worker role while meeting the SLA criteria of having at least 2 instances of each role you are essentially creating 4 billable instances (2 Web Role instances and 2 Worker role instances)
You can definitely run a service within a web role if that suits your purposes and save on the worker instances. In that case you'd only have 2 billable instances.
No the VM role is a completely difference role type and you are not running a VM role by running Web/Workers. You can always safely RDP into the instances irrespective of the role type (However the merit of such an act is questionable once you are in production).