Override MachineKey on Microsoft Azure App Services across multiple App Service Plan

Question

I'm trying to set the Machine Key in Web.Config of ASP.Net MVC apps but it sounds like Azure automatically provision unique machine keys for each web app and override what's in my Web.Config.

The reason I want to do that is because I have an App Service witch is used as Authentication App. Thats where users will login. And I also have plenty others apps that will be using the Token provided by the first app. Doing this will Authenticate users at one unique place and users will be able to navigate through some modules in a portal being authenticated only once. It works very well in localhost or hosted in IIS, but on Azure Hosted App Service it seems like Machine Key aren't read properly or something even if I reset the machine-key configuration section upon Application_Start.

I tried the solution described Here , but as @gorillapower said

Seems this isnt working for us. We are using .NET 4.6.1 and using OWIN startup with app.UseCookieAuthentication() and using a Redis cache session provider. I implemented the above, but the user keeps getting logged out after a slot swap. Any ideas?

It also seems that when you run an ASP.NET application on multiple instances of an App Service Plan (ASP) you do not need to worry about machineKeys as the App Service Platform will use the same one across all your instances and therefore will not need to make any changes to your application.

But in my case, our Apps are all in different App Service Plan. So this solution doesn't apply.

Any clues about this problem ? Thanks

Answer 1

Generate machine Key and add into web.config file

It will work for Web Farm / load balancer either in IIS or Azure Web App service. Note : It will only work if you are using IAppBuilder->UseCookieAuthentication-> CookieAuthenticationOptions

<system.web>
    <authentication mode="None" />
    <machineKey validation="HMACSHA256" decryption="AES" validationKey="D6883865C0490AFA4907A046E838DD2C7B13B636694B552630C13770701B944A" decryptionKey="2C3C48562E6FE018E71B69BDB27D06048A573C094A962AA9A1547C3D874C63B0" />