Скачать или смотреть Understanding Application Initialization in IIS: How to Keep Your .NET 6 MVC App Warm

Learn how application initialization works in IIS and how to keep your .NET 6 MVC app always ready for requests. Discover the importance of the Application Initialization role and the Preload setting.
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Understanding Application Initialization in IIS: How to Keep Your .NET 6 MVC App Warm

In today's fast-paced web environment, ensuring that your applications are always ready to serve requests is crucial. A common issue developers face when deploying applications on Internet Information Services (IIS) is keeping their apps “warmed up” after application pool recycles. This guide will explore how application initialization in IIS works, the importance of the Application Initialization feature, and how to set it up correctly for your .NET 6 MVC application.

The Problem at Hand

When configuring an IIS website to be always up and running, especially for .NET applications, many developers wonder about the specifics behind the various settings available in the web server. For example, you might find the Preload enabled setting available and wonder why it didn't work until you installed the Application Initialization role.

Key Concerns:

What does the Preload enabled setting do if the Application Initialization role is not installed?

If you remove the Home page, will auto preloading stop working? What adjustments need to be made in the config file?

The Role of Application Initialization

What is Application Initialization?

The Application Initialization feature is part of the IIS architecture beginning with IIS 8. While previous versions (IIS 7 and 7.5) required a separate installation, IIS 8 integrated this capability into its core functionalities.

Availability of Features:

Starting with IIS 8, installing the Application Initialization role or feature is essential for proper application warmup processes.

If the role is not installed, the Preload enabled setting simply does not function.

What is the Preload enabled Setting?

The Preload enabled setting is designed to proactively warm up your application. However, without the Application Initialization installed, this setting will not initiate a request to your application. So:

Conclusion: The Preload enabled option without the Application Initialization role will not trigger any actions.

Ensuring Your App is Always Warm

Now that you understand the necessity of installing the Application Initialization role, let's look at how to configure it correctly to ensure your application always warms up properly.

Steps to Set Up Application Initialization

Install Application Initialization Role:
Ensure this role is installed on your server. This step is critical to enable the preloading features.

Update Your Web Config:
You need to specify the paths where the application should send requests. Here’s how to configure your web.config file properly:

[[See Video to Reveal this Text or Code Snippet]]

Replace "/CustomWarmupPage" with the relevant path that should handle warmup requests.

Set Application Pool Properties:
To ensure the app is effectively warmed up:

Set the Application Pool Start Mode to AlwaysRunning.

Set the Website PreLoad Enabled setting to true.

Impact of Removing the Home Page

If you decide to remove the Home page from your application, you need to take a couple of actions to maintain the warmup process:

Fallback Initialization Page: If the default landing page is removed, ensure you configure an alternative page for initialization in the web.config.

Use the Initialization Setting: As shown previously, set the path to a custom warmup page to ensure the app is still preloaded, even without the Home page.

Summary

Setting up and understanding Application Initialization in IIS is vital for any ASP.NET application that aims to provide seamless user experiences without lag during startup. By installing the Application Initialization role and configuring the ne