demo config for nginx http upstream check

ngx_http_upstream_check.conf

upstream cluster {
    # simple round-robin
    server 127.0.0.1:10002;
    server 127.0.0.1:10003;

    check interval=1000 rise=2 fall=5 timeout=500 type=http;
    check_http_send "GET /status HTTP/1.0\r\n\r\n";
    check_http_expect_alive http_2xx http_3xx;
}
server {
    listen       10001;

    location / {
        proxy_pass http://cluster;
    }

    location = /up-status {
        check_status;

        access_log   off;
    }
}
server {
    listen       10002;
    root   html;
    location / {
        index  index.html index.htm;
    }
}
server {
    listen       10003;
    root   html;
    rewrite ^/status$ /status-3 break;

    location / {
        index  index.html index.htm;
    }
}