Introducing backend healthchecking plugin

[Piotr Sikora]

> The only philosophical objection I have to this style is having
> something to do on the LB servers to change and upstream status. I
> wanted a facility wherein something can be done on the upstream server
> (rm the health check file) to remove it out of service.
>
> I come from a world wherein any sort of access on the LB servers is
> tightly controlled and the people managing the upstreams (application
> servers) can plan a maintanence without ever involving the LB folks.
>
> Am also not a fan of the supervisord_start/supervisord_stop directives
> since managing the security aspects of it becomes a hassle.
>
> I am however a fan of supervisord_inherit_backend_status which is why I
> wanted to integrate it with the health-check plugin :-)

I can see your point.

The question which arises now is:
Should health-check or any other ngx_supervisord-aware load balancer be able 
to "enable" backend server which was administratively taken out of the 
rotation with "server A.B.C.D down;" in nginx.conf?

Best regards,
Piotr Sikora < piotr.sikora at frickle.com >