# Вопрос по перебору бэкендов

Maxim Dounin mdounin at mdounin.ru
Sat Feb 21 02:22:28 MSK 2009

```Hello!

On Sat, Feb 21, 2009 at 12:57:01AM +0300, Михаил Монашёв wrote:

> Здравствуйте.
>
> Заметил в логах вот такие строчки:
>
> 20/Feb/2009:21:06:23 +0300 502 "502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502" 0.052 "0.001, 0.001, 0.000, 0.005, 0.001, 0.000, 0.001, 0.000, 0.001, 0.004, 0.001, 0.000, 0.001, 0.000, 0.001, 0.003, 0.000, 0.001, 0.000, 0.001, 0.000, 0.003, 0.001, 0.000, 0.000, 0.001, 0.000, 0.002, 0.001, 0.000, 0.000, 0.001, 0.000, 0.001, 0.001, 0.000, 0.001, 0.000, 0.001, 0.000, 0.001, 0.000, 0.001, 0.000, 0.000, 0.001, 0.001, 0.000, 0.001, 0.000, 0.002, 0.000, 0.001, 0.000, 0.001, 0.001, 0.001, 0.000, 0.001, 0.000, 0.001, 0.001, 0.001, 0.000, 0.001, 0.000, 0.001" "1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.5:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.4:80" 84.42.151.118 354 narutolee.beon.ru "GET / HTTP/1.1" "http://images.google.com/imgres?imgurl=http://i61.beon.ru/11/41/94111/92/4044992/461049Naruto_x_Hinata___Rasengan_by_Pia_sama.jpeg&imgrefurl=http://narutolee.beon.ru/&usg=__6dzK7SqWZFVi_5lYbUu2XFwJI0A=&h=366&w=300&sz=39&hl=ru&start=49&um=1&tbnid=8KiGppQD0L0zsM:&tbnh=122&tbnw=100&prev=/images%3Fq%3Dnaruto%26start%3D40%26ndsp%3D20%26um%3D1%26hl%3Dru%26sa%3DN" "Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.9.0.6) Gecko/2009011913 Firefox/3.0.6"
>
> 20/Feb/2009:21:06:31 +0300 502 "502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502, 502" 0.065 "0.001, 0.000, 0.001, 0.002, 0.000, 0.000, 0.001, 0.000, 0.001, 0.002, 0.000, 0.000, 0.001, 0.000, 0.001, 0.002, 0.001, 0.000, 0.000, 0.001, 0.000, 0.002, 0.000, 0.000, 0.001, 0.000, 0.001, 0.002, 0.000, 0.000, 0.001, 0.001, 0.000, 0.002, 0.001, 0.000, 0.000, 0.001, 0.000, 0.002, 0.000, 0.001, 0.000, 0.001, 0.000, 0.002, 0.001, 0.000, 0.000, 0.001, 0.000, 0.002, 0.001, 0.000, 0.000, 0.001, 0.000, 0.002, 0.001, 0.000, 0.001, 0.000, 0.001, 0.002, 0.001, 0.000, 0.001, 0.000, 0.001, 0.002, 0.000, 0.000, 0.001, 0.000, 0.000, 0.002, 0.001, 0.000, 0.001, 0.000, 0.001, 0.000, 0.001, 0.000, 0.001, 0.001, 0.000, 0.001, 0.000, 0.001, 0.001, 0.000, 0.001, 0.000, 0.001, 0.000, 0.001" "1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 127.0.1.8:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.5:80, 1.2.3.4:80, 1.2.3.5:80, 1.2.3.6:80, 1.2.3.7:80, 1.2.3.8:80, 1.2.3.4:80" 92.112.23.162 354 279.beon.ru "GET /54-095-test-dlja-devochek-anna-tochno.zhtml HTTP/1.1" "http://yandex.ru/yandsearch?text=%D0%BE%D0%BD%D0%BB%D0%B0%D0%B9%D0%BD+%D0%B8%D0%B3%D1%80%D1%8B+%D0%B4%D0%BB%D1%8F+%D0%B4%D0%B5%D0%B2%D0%BE%D1%87%D0%B5%D0%BA+%D0%BD%D0%B0+%D0%BF%D0%BE%D1%86%D0%B5%D0%BB%D1%83%D0%B8&stpar2=%2Fh1%2Ftm29%2Fs4&stpar4=%2Fs4&stpar1=%2Fu1&stpar3=%2Fm4%2Ftc34%2Fnc1&lr=187" "Opera/9.62 (Windows NT 5.1; U; ru) Presto/2.1.1"
>
> Конфигурация апстрима вот такая:
>
>         upstream  my_backends  {
>                 server  127.0.1.8:80    weight=1        max_fails=20    fail_timeout=3s;
>                 server  1.2.3.4:80   weight=5000     max_fails=1000  fail_timeout=3s;
>                 server  1.2.3.5:80   weight=10000    max_fails=1000  fail_timeout=3s;
>                 server  1.2.3.6:80   weight=16000    max_fails=1000  fail_timeout=3s;
>                 server  1.2.3.7:80   weight=16000    max_fails=1000  fail_timeout=3s;
>                 server  1.2.3.8:80   weight=16000    max_fails=1000  fail_timeout=3s;
>                 server  1.2.3.4:80   backup;
>                 server  1.2.3.5:80   backup;
>                 server  1.2.3.6:80   backup;
>                 server  1.2.3.7:80   backup;
>                 server  1.2.3.8:80   backup;
>         }
>
> Я   правильно   понимаю,   что  апстрим  знает  только  про  последний
> запрошенный  бэкенд и может отправлять один запрос по кругу даже на те
> бэкенды, которые ранее на него вернули ошибку?

Нет, не правильно.  В обычных условиях nginx помнит, куда он уже
сходил, и больше туда не ходит.  Это бага в реализации backup
серверов.

Maxim Dounin

```