load balancer behavior during server crash in clustered environment

0
votes

I got a query regarding a response from cluster of managed server (Weblogic) behind load balancer.

During a request to server (though load balancer) if server crashes then does response goes back to client OR load balancer re-route the request to another running server in that cluster (stateful request)

so the workflow is something like this:

Client request -> server1 -> crashed in between processing request -> reponse back to app -> send back to server -> load balancing-> to another running server.

does it go to client in case of crash server response

OR

Load Balancer handles the response and see that server crash response received and hence it re-request (without even client letting know about this whole crashing scene)

1
weblogic

1 Answers

0
votes

Depends on the Load Balancer, depends on the vendor, depends on the module and method. Your question is vague. This is what a load balancer should be configured to do. It comes built in for some load balancers like Apache and might have to be specifically configured for some others.

The load balancer should probe your application page, for example if you have an application running on http://example.com:9101/index.html, then every 15 seconds(say) it will probe the page and ensure the application is up and send traffic to it. If not, it will send it to the other members defined. So if the server crashes, it will know and stop sending. Most commercial and free load balancers have to option to be configured to do so, so does the weblogic load balancer.

Without more information, this is the most general answer I can provide.