Proxy server which allows to switch between two destination servers using a lock file.
There is an example init.d script in scripts/init.d/turnout.example - adjust it to your needs.
Also there is an example Apache httpd config snippet in scripts/httpd/conf.d/turnout_proxy.example.conf - adjust to your needs. WARNING this config is insecure!
$ gem install turnout_proxy
$ turnout_proxy --help