When it comes to hosting web applications on Microsoft Azure, one might wonder what web server is being used. The answer is quite simple – Azure App Service uses Kestrel as its default web server.
Kestrel is a cross-platform web server that was developed by Microsoft. It is lightweight, efficient, and highly scalable, making it an excellent choice for hosting web applications on Azure.
Why Kestrel?
One of the main reasons why Azure App Service utilizes Kestrel as its default web server is its ability to handle a large number of concurrent connections efficiently. This is achieved through the use of asynchronous programming and non-blocking I/O operations.
Kestrel also provides excellent performance due to its integration with the .NET Core runtime. It takes full advantage of the performance improvements introduced in .NET Core, such as JIT (Just-In-Time) compilation and runtime optimizations.
Scalability and Load Balancing
Azure App Service automatically scales your application based on demand. When traffic increases, additional instances of your application are spun up to handle the increased load. Kestrel works seamlessly with Azure’s load balancer to distribute incoming requests across these instances.
This built-in scalability and load balancing feature ensures that your application can handle high traffic volumes without any downtime or performance issues.
Customization Options
In addition to being the default web server for Azure App Service, Kestrel also offers various customization options to suit your needs. You can configure Kestrel using appsettings.json or programmatically in your application’s startup code.
- TLS/SSL Configuration: You can configure Kestrel to use TLS/SSL certificates for secure communication.
- Request Filtering: Kestrel allows you to define request filtering rules to block or allow specific requests based on various criteria.
- Logging: Kestrel provides logging capabilities that allow you to monitor and troubleshoot your application.
Using Other Web Servers
While Kestrel is the default web server for Azure App Service, it is worth mentioning that you can also use other web servers if needed. Azure App Service supports running applications behind a reverse proxy, allowing you to use popular web servers such as NGINX or IIS.
This flexibility enables you to leverage the features and capabilities of different web servers while still benefiting from the scalability and manageability offered by Azure App Service.
In conclusion,
Azure App Service utilizes Kestrel as its default web server due to its lightweight nature, scalability, and performance. With its integration with .NET Core and seamless load balancing capabilities, Kestrel provides an excellent hosting environment for web applications on Azure. Additionally, Kestrel offers customization options and the flexibility to use other web servers if desired.
Note: While Kestrel is a powerful web server, it is recommended to use it behind a reverse proxy like NGINX or IIS for production scenarios, as they provide additional security features and performance optimizations.