Huh?

A simple servlet that can be used to play around with load balancer probes, proxy configurations, server pools etc. Launch a few instances, configure your load balancer / proxy / whatever and start hammering while changing the response on the instances.

nginx upstream example

1. Jetty

Launch a couple of jetty's in the root of this project:

mvn -Djetty.port=9997 jetty:run
mvn -Djetty.port=9998 jetty:run
mvn -Djetty.port=9999 jetty:run

2. nginx:

Confgure nginx along the lines of:

upstream jetty {
    server 127.0.0.1:9997;
    server 127.0.0.1:9998;
    server 127.0.0.1:9999;
}
server {
    listen 8080;
    server_name 127.0.0.1;
    proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
    location / {
        proxy_pass                  http://jetty;
        proxy_redirect              off;
        proxy_buffering             off;
        proxy_set_header            host            $http_host;
        proxy_set_header            x-real-ip       $remote_addr;
    }
}

3. Requests:

Start doing requests against nginx:

while [ 1 ]; do curl http://127.0.0.1:8080/; done

4. Experiment

• bring up a JMX console against the jetty instances and play around with various combinations of response codes until you find something that works in this dust
• mark one or more of the upstream servers as "backup" in nginx.conf, reload the configuration mid-flight (nginx -s reload) and play with the response codes
• experiment with various combinations of values for the proxy_next_upstream field