Docker proxy based on nginx to have zero downtime deployments. It exposes two ports so you can preview your next version before switching your live system. Port 80 is meant for your live system and this is where your main load balancer should point to. You can setup a secondary load balancer which points to port 8080 so you can preview your next version.

docker build -t docker-proxy .

Start the proxy with the following command:

docker run -d -v /var/run/docker.sock:/var/run/docker.sock -p 80:80 -p 8080:8080 --name docker-proxy docker-proxy

Of course you can use different ports like -p 5000:80 -p 5001:8080 or just expose port 80 if you don’t need the second port to preview a release.

Start your dockerized application and then run

docker exec -it docker-proxy proxy1 <CONTAINER_ID>

to switch proxy 1 to that container. You can now access this application on port 80 (or whatever port you exposed port 80 on).

When you release a new version start the new container and run

docker exec -it docker-proxy proxy2 <NEW_CONTAINER_ID>

to be able to preview it on port 8080.

When everything looks good just run

docker exec -it docker-proxy proxy1 <NEW_CONTAINER_ID>

to release the new version on the main port.