Azure Web App Deployment Slots Pricing
Back when we all used Azure Cloud Services for running websites and backend worker tasks, we had the fabulous concept of deployment slots. Since January 2014, this concept was also introduced in the offering than called Azure Websites. Now, in Azure App Services Web Apps, the concept is still alive.
What is a deployment slot?
Deployment slots are very useful service from Azure cloud services, this isolate enviorment for developers to develope and test the codes in a seamless manner.The feature swap, enable the developers to rapid deployment and easy roll out roll back. For an example your web users connected and accessing the original production site on the. 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. Azure Deployment Slots – a brief introduction. Deployment Slots are a capability of Azure Web Apps (previously known as Azure Websites). They are only available when you’re using a Standard or Premium pricing plan. If you go into the “Settings” area of your web app, you can click into “Deployment Slots” and from here create a slot. Azure deployment slots are a fantastic feature of Azure App Services. They allow developers to have multiple versions of their application running at the same time with the added bonus of being able to re-route traffic between each instance at the press of a button.
Basically, a deployment slot is another Web App that runs next to your original one. This means that you could create a deployment slot for your production environment and call that the pre-production slot, or staging slot, as in the illustration below:
At the time of this writing, you can create up to:
- 4 slots for Web Apps in the standard tier in addition to production
- 19 slots in the premium tier in addition to production
Note that a deployment slot is a fully fledged Web App, hosted in the same pricing tier as the Web App it is spawned from. Therefore it will incur costs.
Benefits
Using a deployment slot can provide the following benefits:
- Test it in pre-production - you can deploy a pre-production version of your site and test it before it goes into production. You can do functional and automated testing on this, and also use it to do performance testing, to make sure that everything is alright without testing in production
- Easily deploy - once you are happy that your website in the staging slot works as expected, you can use the swap function (or even use Auto Swap) to get your version seamlessly in production.
- What happens here, is that the Virtual IP Address of the swap target (in my example the production slot) is re-pointed to the swap source (the staging slot) and vice versa.
- Also, before the swap happens, the website in the staging slot is pre-warmed to make sure that the website is ready to go when you swap it
- These mechanisms ensure that there is no downtime when you swap and makes for a great deployment mechanism
- Revert deployment - If for whatever reason, you’re not happy with the result of website now in production, you can easily revert back to the situation that was working before by swapping back to the staging slot
Limitations
- You cannot use linked resource management in a non-production slot
- You cannot scale out a non-production slot (meaning that you cannot scale the number of instances)
Traffic Routing
Traffic Routing (previously called testing in production), can help you with doing A/B testing (actual testing in production).
You can set it up to route a percentage of all traffic to one or more deployment slots, as in the illustration below. By doing this, users are redirected to your deployment slot and they are testing in “production”.
Azure Web App Deployment Slots Pricing Guide
Take advantage of deployment slots. It’s a simple enough mechanism to use with huge benefits. Try it out!