implement upstream max_conns in lua

david.birdsong · 2015-04-21T03:08:31+00:00

> As we are at a limit with our OpenResty+Redis architecture, we are > thinking to add additional Redis instances, to increase throughput. > I read...

implement upstream max_conns in lua

david.birdsong

Hi, I'd like to make upstream decisions based on current connection counts or even better, upstream connection counts.

I haven't found any variables supplied by nginx core that could help me track. Does such a value exist? Is there some API that I can read to count connections?

info

See http://nginx-win.ecsds.eu/devtest/EBLB_upstream_dev3.zip
and https://github.com/vozlt/nginx-module-vts

On Monday, April 20, 2015 at 9:08:33 PM UTC+2, David Birdsong wrote:

Hi, I'd like to make upstream decisions based on current connection counts or even better, upstream connection counts.

I haven't found any variables supplied by nginx core that could help me track. Does such a value exist? Is there some API that I can read to count connections?

agentzh

Hello!

On Tue, Apr 21, 2015 at 3:08 AM, David Birdsong wrote:
> Hi, I'd like to make upstream decisions based on current connection counts
> or even better, upstream connection counts.
>

Have you looked at the standard least connection upstream balancer module?

http://nginx.org/en/docs/http/ngx_http_upstream_module.html#least_conn

Also, the standard ngx_limit_conn module may also be relevant here:

http://nginx.org/en/docs/http/ngx_http_limit_conn_module.html

> I haven't found any variables supplied by nginx core that could help me
> track. Does such a value exist? Is there some API that I can read to count
> connections?
>

See above.

FWIW, once the balancer_by_lua directive of the ngx_lua module is
opensourced (it is already implemented internally in CloudFlare), such
tasks would be trivial for a little bit of Lua :)

Best regards,
-agentzh

david.birdsong

On Tue, Apr 21, 2015 at 2:09 AM <i...@ecsystems.nl> wrote:

See http://nginx-win.ecsds.eu/devtest/EBLB_upstream_dev3.zip
and https://github.com/vozlt/nginx-module-vts

Thanks for these links. The module is really cool, I'll probably check it out for monitoring.

I do need something that can be examined in path of a request though, so I was hoping to find an in-memory reference that could be examined for making routing decisions.

On Monday, April 20, 2015 at 9:08:33 PM UTC+2, David Birdsong wrote:
Hi, I'd like to make upstream decisions based on current connection counts or even better, upstream connection counts.

I haven't found any variables supplied by nginx core that could help me track. Does such a value exist? Is there some API that I can read to count connections?

.

david.birdsong

On Thu, May 7, 2015 at 5:57 AM Yichun Zhang (agentzh) <age...@gmail.com> wrote:

Hello!

On Tue, Apr 21, 2015 at 3:08 AM, David Birdsong wrote:
> Hi, I'd like to make upstream decisions based on current connection counts
> or even better, upstream connection counts.
>

Have you looked at the standard least connection upstream balancer module?

http://nginx.org/en/docs/http/ngx_http_upstream_module.html#least_conn

Also, the standard ngx_limit_conn module may also be relevant here:

http://nginx.org/en/docs/http/ngx_http_limit_conn_module.html

> I haven't found any variables supplied by nginx core that could help me
> track. Does such a value exist? Is there some API that I can read to count
> connections?
>

See above.

FWIW, once the balancer_by_lua directive of the ngx_lua module is
opensourced (it is already implemented internally in CloudFlare), such
tasks would be trivial for a little bit of Lua :)

great, this is exactly what I was hoping for. i look forward to seeing that come out.

i scour cloudflare's github page frequently, but will you post it here on the list when it comes out?

Best regards,
-agentzh.

agentzh

Hello!

On Fri, May 8, 2015 at 3:15 AM, David Birdsong wrote:
>
> i scour cloudflare's github page frequently, but will you post it here on
> the list when it comes out?
>

Yes, sure. There will be an announcement here when the balancer_by_lua
thing is opensourced.

Regards,
-agentzh