> Did you look at ngx_supervisord[1]?

Do you mean use only ngx_supervisord? From what I can tell, it requires a separate daemon running on the machine that does the healthcheck, which then sends a call to nginx via supervisord to turn servers off or on. Is that correct? The goal was to build the checking into nginx so that we don't have to monitor another process, making the system more stable. If nginx is running, then you're guaranteed the health checks are running.

Or did you mean call into ngx_supervisord when a healthcheck fails? I'm happy to integrate other APIs if you have some ideas.