Separated containers for nginx and docker-gen

[andrefernandes]

It kinda creeps me out having a docker.sock mount specially on the nginx node.

It could be a better approach to have nginx and docker-gen on different containers but sharing the "/etc/nginx/sites-enabled" mount (actually the "official" nginx image exposes this volume).

This way only the docker-gen image needs to mount docker.sock.

I prefer, at this moment, using "fig" to define multi-container deployments.

[andrefernandes]

Needless to say, that makes "forego" unnecessary too.

[andrefernandes]

I am still trying to figure things out, but I believe that you can:

a) mount the docker binary on the docker-gen container (as you do with the socket)
b) send the nginx reload signal (SIGHUP I think) with docker kill

Let's say nginx container is named "web":

CID=$(docker inspect --format "{{ .Id }}" web)
docker kill --signal="SIGHUP" $CID

[andrefernandes]

Nice, got it to work on:

https://github.com/andrefernandes/docker-gen

https://github.com/andrefernandes/docker-nginx

Both nginx and docker-gen containers share a volume. Nginx container knows nothing about docker-gen and gets to reload when SIGHUP signals come.

Feels nice :)

[jwilder]

Nice. @vaceletm did something similar using inotify in #5.

While I understand the concern about the docker socket bound into the container, I'd rather keep nginx-proxy simple to run and get productive. I've been thinking of having a docker-gen image that would work w/ the offical nginx image (or others) as well but have not had time to experiment with it yet. It would an alternative nginx-proxy setup that I'd add to the documentation. Using fig to start the two seems like a good idea.

[jwilder]

docker-gen 0.3.4 has a new feature that should make running nginx and docker-gen in separate containers easier. There is a new -notify-sighup that will sighup a container. It could be used to sighup an nginx container. 0.3.4 should also work better with shared volumes between containers.