# High CPU when upstream server down **URL:** \ **Category:** NGINX\ **Created:** [March 8, 2011, 9:12pm UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262 "2011-03-08T21:12:15Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\ **Post date:** [March 8, 2011, 9:12pm UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/1 "2011-03-08T21:12:15Z")
Nginx goes to nearly 100% CPU when I take down my upstream servers (gunicorn). Has anybody heard of this as an issue? $ nginx -v nginx version: nginx/0.7.67 $ uname -a Linux ip-10-242-226-66 2.6.35-27-virtual #48-Ubuntu SMP Tue Feb 22 23:09:12 UTC 2011 i686 GNU/Linux Summary of top: top - 20:10:17 up 1 day, 29 min, 4 users, load average: 1.11, 0.83, 0.56 Tasks: 79 total, 2 running, 77 sleeping, 0 stopped, 0 zombie Cpu(s): 6.4%us, 36.9%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 56.7%st Mem: 1705708k total, 442308k used, 1263400k free, 91240k buffers Swap: 917500k total, 0k used, 917500k free, 249920k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 30663 www-data 20 0 5492 1944 916 R 99.9 0.1 5:26.32 nginx ``` 1 root 20 0 2848 1652 1216 S 0.0 0.1 0:00.47 init 2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd 3 root 20 0 0 0 0 S 0.0 0.0 0:03.74 ksoftirqd/0 4 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0 5 root RT 0 0 0 0 S 0.0 0.0 0:00.20 watchdog/0 6 root 20 0 0 0 0 S 0.0 0.0 0:01.91 events/0 7 root 20 0 0 0 0 S 0.0 0.0 0:00.00 cpuset ``` Posted at Nginx Forum: > **[High CPU when upstream server down](https://forum.nginx.org/read.php?2,181397,181397#msg-181397)** > > Nginx goes to nearly 100% CPU when I take down my upstream servers (gunicorn). Has anybody heard of this as an issue? $ nginx -v nginx version: nginx/0.7.67 $ uname -a Linux ip-10-242-226-66 2.6.35-27-virtual #48-Ubuntu SMP Tue Feb 22 23:09:12 UTC... ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 8, 2011, 9:18pm UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/2 "2011-03-08T21:18:34Z")
On Tue, Mar 8, 2011 at 2:10 PM, adamn [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Nginx goes to nearly 100% CPU when I take down my upstream servers > (gunicorn). Has anybody heard of this as an issue? ## Configuration file? I would suspect something causing an endless loop of redirects or something like that. I did similar to myself in a QA environment a while back with an ill-concieved “catch-all” dynamic error\_page. RPM ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 8, 2011, 9:36pm UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/3 "2011-03-08T21:36:07Z")
Using the same config file - everything works fine and this is not reproducible on 0.8.54. Here is my config. Keep in mind that the upstream and server section are in reality 8 upstreams and servers - most of which are exactly the same with the exception of the server\_name and the unix socket filename. user www-data; worker\_processes 1; error\_log /var/log/nginx/error.log debug; pid /var/run/nginx.pid; events { worker\_connections 1024; # multi\_accept on; } http { include /etc/nginx/mime.types; ``` access_log /var/log/nginx/access.log; sendfile on; #tcp_nopush on; #keepalive_timeout 0; keepalive_timeout 65; tcp_nodelay on; gzip on; gzip_disable "MSIE [1-6]\.(?!.*SV1)"; upstream dev.example.com { server unix:/tmp/gunicorn_dev.example.com.sock; # For a TCP configuration: #server 127.0.0.1:8000; } server { listen 80; client_max_body_size 4G; server_name dev.example.com; keepalive_timeout 5; # path for static files root /var/www/dev-example-env/example/media; location = /favicon.ico { alias /var/www/dev-example-env/example/media/favicon.ico; } location = /robots.txt { alias /var/www/dev-example-env/example/media/no_robots.txt; } location /img { alias /var/www/dev-example-env/example/media/img/; } location /admin_media { alias ``` /var/www/dev-example-env/lib/python2.6/site-packages/django/contrib/admin/media/; } ``` location / { auth_basic "Restricted"; auth_basic_user_file ``` “/var/www/dev-example-env/example/.htpasswd”; ``` proxy_set_header X-Forwarded-For ``` $proxy\_add\_x\_forwarded\_for; proxy\_set\_header Host $http\_host; proxy\_redirect off; ``` if (!-f $request_filename) { proxy_pass http://dev.example.com; break; } } error_page 500 502 503 504 /500.html; location = /500.html { alias /var/www/dev-example-env/example/templates/500.html; } } ``` } Posted at Nginx Forum: > **[Re: High CPU when upstream server down](https://forum.nginx.org/read.php?2,181397,181406#msg-181406)** > > Nginx goes to nearly 100% CPU when I take down my upstream servers (gunicorn). Has anybody heard of this as an issue? $ nginx -v nginx version: nginx/0.7.67 $ uname -a Linux ip-10-242-226-66 2.6.35-27-virtual #48-Ubuntu SMP Tue Feb 22 23:09:12 UTC... ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 8, 2011, 10:46pm UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/4 "2011-03-08T22:46:20Z")
On Tue, Mar 8, 2011 at 2:35 PM, adamn [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ``` > if (!-f $request_filename) { > proxy_pass http://dev.example.com; > break; > } > > ``` As they say, [GitHub - nginxinc/nginx-wiki: ARCHIVED -- Source for the now archived NGINX Wiki section of https://www.nginx.com · GitHub](http://wiki.nginx.org/IfIsEvil) I’ve never seen proxy\_pass work correcly inside an if block; the fact that it works for you on 0.8.x seems to be happy coincidence. Try creating a separate location (maybe regex based if necessary) and put your proxy\_pass statement in there. – RPM ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 9, 2011, 1:35am UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/5 "2011-03-09T01:35:09Z")
Just got rid of the if entirely. That logic was totally unnecessary so now it’s just: ``` proxy_pass http://dev.example.com; ``` Posted at Nginx Forum: > **[Re: High CPU when upstream server down](https://forum.nginx.org/read.php?2,181397,181459#msg-181459)** > > Nginx goes to nearly 100% CPU when I take down my upstream servers (gunicorn). Has anybody heard of this as an issue? $ nginx -v nginx version: nginx/0.7.67 $ uname -a Linux ip-10-242-226-66 2.6.35-27-virtual #48-Ubuntu SMP Tue Feb 22 23:09:12 UTC... ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 8, 2011, 11:04pm UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/6 "2011-03-08T23:04:35Z")
Heh - All I did was copy the docs 🙂 [http://gunicorn.org/deploy.html](http://gunicorn.org/deploy.html) I’ll work out a solution and post it back. Cheers, Adam Posted at Nginx Forum: > **[Re: High CPU when upstream server down](https://forum.nginx.org/read.php?2,181397,181435#msg-181435)** > > Nginx goes to nearly 100% CPU when I take down my upstream servers (gunicorn). Has anybody heard of this as an issue? $ nginx -v nginx version: nginx/0.7.67 $ uname -a Linux ip-10-242-226-66 2.6.35-27-virtual #48-Ubuntu SMP Tue Feb 22 23:09:12 UTC... ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 9, 2011, 4:20am UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/7 "2011-03-09T04:20:52Z")
On Tue, Mar 8, 2011 at 4:02 PM, adamn [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Heh - All I did was copy the docs 🙂 > > [http://gunicorn.org/deploy.html](http://gunicorn.org/deploy.html) > > I’ll work out a solution and post it back. As far as I can tell, that site is in no way affiliated with Igor or any of the other nginx developers. The authoritative site for nginx is [nginx.org](http://nginx.org) (and the links from there). – RPM ---
**Author:** ![adamn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/ea666f/32.png) [@adamn](https://www.ruby-forum.com/u/adamn)\ **Post date:** [March 9, 2011, 4:34am UTC](https://www.ruby-forum.com/t/high-cpu-when-upstream-server-down/204262/8 "2011-03-09T04:34:04Z")
That is true. Unfortunately there is no documentation on the nginx site regarding gunicorn. Posted at Nginx Forum: > **[Re: High CPU when upstream server down](https://forum.nginx.org/read.php?2,181397,181484#msg-181484)** > > Nginx goes to nearly 100% CPU when I take down my upstream servers (gunicorn). Has anybody heard of this as an issue? $ nginx -v nginx version: nginx/0.7.67 $ uname -a Linux ip-10-242-226-66 2.6.35-27-virtual #48-Ubuntu SMP Tue Feb 22 23:09:12 UTC...