Restarting Containers When Using Docker and Nginx proxy_pass

Question

I have an nginx docker container and a webapp container successfully running and talking to eachother.

The nginx container listens on port 80, and uses proxy_pass to direct traffic to the IP of the webapp container.

upstream app_humansio { server humansio:8080 max_fails=3 fail_timeout=30s; }

"humansio" is set in the /etc/hosts file by docker because I've started nginx with --link humansio:humansio. The webapp container (humansio) is always exposing 8080.

The problem is, when I reload the webapp container, the link to the nginx container breaks and I need to restart that as well. Is there any way I can do this differently so I don't need to restart the nginx container when the webapp container reloads?

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I've tried to do something like connecting them manually by using a common port (8001 on both), but since they actually reserve that port, the 2nd container cannot use it as well.

Thanks!

Answer 1

I prefer to run the proxy (nginx of haproxy) directly on the host for this reason.

But an option is to "Link via an Ambassador Container" https://docs.docker.com/articles/ambassador_pattern_linking/

https://www.digitalocean.com/community/tutorials/how-to-use-the-ambassador-pattern-to-dynamically-configure-services-on-coreos

Answer 2

If you don't want to restart your proxy container whenever you have to restart one of the proxied ones (e.g. fig), you could take a look at the autoupdated proxy configuration approach: http://jasonwilder.com/blog/2014/03/25/automated-nginx-reverse-proxy-for-docker/