Nginx + PHP-FPM: 502 Bad Gateway, first Nginx request seems to disconnect PHP-FPM in some way

[siccovansas]

I'm using Nginx together with PHP-FPM, both in their own container. At first the PHP-FPM container looks fine as a request using cgi-fcgi gives me a response. But once I make a call to my website I get a 502 Bad Gateway error and cgi-fcgi also states that it can't connect after this.

I managed to fix this again though. I exec into the PHP-FPM container and put out a request, e.g., curl 'http://google.com' or apt-get update. After doing this my website works again (and thus cgi-fcgi works as well).

This is my docker-compose.yml:

c-nginx:
    image: nginx:1.9.9
    volumes:
        - ../www:/usr/share/nginx/html
        - ./nginx.conf:/etc/nginx/nginx.conf:ro
        - ./nginx-site.conf:/etc/nginx/conf.d/default.conf:ro
        - ./restrictions.conf:/etc/nginx/global/restrictions.conf:ro
    links:
        - c-php-fpm
c-php-fpm:
    image: php:5.6.16-fpm
    volumes:
        - ../www:/usr/share/nginx/html

I tried PHP-FPM versions 5.6.17 and 7.0.2 as well, but the results were the same.

I also tried using docker run instead of docker-compose, still the same results:

sudo docker run --name c-php-fpm -v /srv/nginx-php/www:/usr/share/nginx/html -d php:5.6.16-fpm
sudo docker run --name c-nginx --link c-php-fpm -v /srv/nginx-php/www:/usr/share/nginx/html -v /srv/nginx-php/docker:/etc/nginx/nginx -v /srv/nginx-php/docker/temp-nginx-site-conf:/etc/nginx/conf.d -v /srv/nginx-php/docker/temp-global:/etc/nginx/global/ -d nginx:1.9.9

It took me quite time to get to this problem description, but I have no idea what is causing this behavior. I want this setup to work out of the box, without this weird fix I use now. So does anybody have any ideas or things for me to try?

[siccovansas]

Ok; so a server reboot fixed this problem. Maybe some zombie processes which were somehow interfering? Other weird stuff? Who knows..

[seyfer]

Had the same problem, googled, but in reality some docker container was zombie or smfng, stopped all, deleted all and run again - all works. Strange.