Introducing backend healthchecking plugin
piotr.sikora at frickle.com
Tue Mar 2 13:21:25 MSK 2010
> 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?
No, it's not :P
Neither ngx_supervisord nor supervisord do any healt-checking.
ngx_supervisord communicates with supervisord (process manager) to
dynamically start or stop backend servers, depending on the load. Since
version 1.3 it also supports supervisord-less configuration which disables
all communication with supervisord daemon (so it basically takes backend
servers out of rotation without the need to reload nginx).
> Or did you mean call into ngx_supervisord when a healthcheck fails? I'm
> happy to integrate other APIs if you have some ideas.
Yeah, that's probably what Grzegorz meant. You would just need to call
ngx_supervisord_execute(uscf, NGX_SUPERVISORD_CMD_STOP, backend_number,
NULL) and then all ngx_supervisord-aware load balancers (upstream_fair,
round_robin & ip_hash) would automagically stop using failed backend until
you would execute NGX_SUPERVISORD_CMD_START.
Full API spec is available at:
At the moment one would need to specify "supervisord none;" in order to
enable supervisord-less configuration, because there is no such call in API,
but I could add this in next release if you would like to use it.
Piotr Sikora < piotr.sikora at frickle.com >
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