Limit proxy_next_upstream

Server NGINX
1

Is it possible to limit the amount of upstreams asked? I have four
upstreams
defined and it makes no sense to ask all of them. If two of them timeout
or
error there is possible something wrong with the request and asking
another
node doesn’t help.

Posted at Nginx Forum:

2

Hello!

On Fri, Apr 05, 2013 at 04:38:36AM -0400, philipp wrote:

Is it possible to limit the amount of upstreams asked? I have four upstreams
defined and it makes no sense to ask all of them. If two of them timeout or
error there is possible something wrong with the request and asking another
node doesn’t help.

No, as of now only switching off proxy_next_upstream completely is
available.

On the other hand, with switched of proxy_next_upstream you may
still configure retries to additional (or other) upstream servers
via error_page directive, using a configuration similar to last
example at Module ngx_http_core_module.

Something like this should generate no more than two requests
regardless of number of upstream servers configured:

location / {
    error_page 502 504 = @fallback;
    proxy_pass http://backend;
    proxy_next_upstream off;
}

location @fallback {
    proxy_pass http://backend;
    proxy_next_upstream off;
}

–
Maxim D.
http://nginx.org/en/donation.html

3

Hello!

On Fri, Apr 05, 2013 at 09:59:29PM +0800, Weibin Y. wrote:

We have the similar request. If we have dozens of servers in a same
upstream block, I don’t want to retry all of them. One side effect is it
will increase the failure count with all of the backend servers. After
several times, all of the servers will be marked down for a while and all
of the requests will be replied with 502.

We also need the retry mechnism and don’t want to diable it. I think if
there is a configurable tries time with the direcitve proxy_next_upstream,
it will be very nice.

This is somewhere in TODO, and likely will be implemented soon.
As usual, the most serious problem is a name for the directive
(proxy_next_tries?). :slight_smile:

Additional similar proposal discussed here includes limiting total
time spent in retries before giving up (proxy_next_time?). This
will allow to try many servers as soon as they, e.g., return RST
quickly, but to only try one or two servers if they fail to answer
in configured proxy_connect_timeout/proxy_read_timeout.

defined and it makes no sense to ask all of them. If two of them timeout
via error_page directive, using a configuration similar to last

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–
Weibin Y.
Developer @ Server Platform Team of Taobao

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–
Maxim D.
http://nginx.org/en/donation.html

4

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5

We have the similar request. If we have dozens of servers in a same
upstream block, I don’t want to retry all of them. One side effect is it
will increase the failure count with all of the backend servers. After
several times, all of the servers will be marked down for a while and
all
of the requests will be replied with 502.

We also need the retry mechnism and don’t want to diable it. I think if
there is a configurable tries time with the direcitve
proxy_next_upstream,
it will be very nice.

2013/4/5 Maxim D. [email protected]

6

Is there any update about this feature?

Posted at Nginx Forum: