IIS Server Load balancer arr route requests to the ARR server and processing server

. NET web uses the IIS Arr (application request route) technology to achieve high web performance, high reliability, scalability, and load balancing. For more information about how to use arr, seeIISServer Load balancer-application request route

For general application scenarios, see the following figure. One server only serves as the ARR server and receives requests from the client. Based on the configured Server Load balancer algorithm, it forwards requests to the real request processing server, for example, server B or C in serverfarm is used by server B or server C to process the request and return the processing result to ARR server a. the ARR server then returns the processing result to the client.

Our arr server is well configured and it is a waste to only use the ARR server. In order to achieve high concurrent access, I want the ARR server to be used as the ARR service as the application server at the same time, that is, the workload is borne by the server in serverfarm. I found a lot of information on the Internet and said it could not be implemented, but I found out that my requirements were met by configuring URL rewrite rules. Assuming that the ARR server provides external services on port 80, after receiving the port 80 request, the server Load balancer will also forward requests to Web applications on port 8080 to process requests or Web applications on port 8080 of other services. General steps

1. Add the ARR server to serverfarm as the Server Load balancer server. Pay attention to the port

Serverfarm list

2. url rewrite rule configuration. The HTTP request of the specified port of the ARR server will be forwarded to the server in serverfarm.

Deployment diagram after implementation

 

Problems and Solutions after using arr:

The arr server can be used as a web static resource (JS, image, and so on) server. By configuring URL rewriting rules, the static resource requests are processed by arr and no longer forwarded to other servers.

After arr is used, the session should not be stored in the process. You must use StateServer or sqlserver for storage. If you stick to the storage in the process, you can choose to use the client affinity (client affinity), that is, all requests of the customer have the same server for response and will not be forwarded to other servers, this sacrifices reliability. When the server fails, the request cannot be forwarded to other servers for service. The result is that the client request has no response.

After arr is used, the Web application files on the server Load balancer are inconsistent (for example, some images are uploaded to the upload folder on server B, server C uploads some images in its own upload folder, but when a user accesses server B and requests an image on server B, server a returns filenotfound and other similar issues), solution: files are uploaded to a single file server (such as server a). Web applications on each server point to a unified file server by configuring virtual directories. Currently, in this way, the upload and read operations are on the Unified File Service A, so that each web application only has its own file and there are no other server files.

 

IIS Server Load balancer arr route requests to the ARR server and processing server