在天蓝色实例中要求自动缩放后过早

Question

Currently I am facing the problem that if I my scaling out rule in applied and new instance is my web app is created it gets request too soon. By that I mean that it is not finished its initialization.

I have read that there is a solution which I can add to my OnStart method. It will be checking instance health and allow requests only after it will pass specified health test.

But I am wondering if there is a way to add such a check somewhere in azure. In case there is, please share it with me.

In case you know any other way to check instance's health you are more than welcome to share it with me.

Thank you.

Answer 1

You can use ApplicationInitialization setting in the web.config file.

you'll need to add something like this:

<applicationInitialization doAppInitAfterRestart="true" skipManagedModules="true">
    <add initializationPage="/" />
    <add initializationPage="/User" />
</applicationInitialization>

Every time your application starts, this can be because of a new worker coming online (horizontal scaling) or even just a cold start caused by a new deployment, config change etc... the ApplicationInitialization will be executed to warm up the site before accepting requests on that worker.

You can read more about this here: http://ruslany.net/2015/09/how-to-warm-up-azure-web-app-during-deployment-slots-swap/

Even though that post is talking about using this for warming up a site when doing a swap operation, it also applies to cold starts, and scale outs.

Reference: How can I make sure a new autoscaled Azure App Service instance is warm before it handles traffic?

Hope this helps.