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I am using docker-compose for deploying several containers on the same host. My images are built in Google Cloud Build and stored on gcr.io; I am not using docker-compose to build my images.

When I run docker-compose pull followed by docker-compose up -d, new containers are created for my images. However, if I run docker ps in another tab, I observe that my containers go offline for a few seconds while the new ones are being created.

Is there a way to tell docker-compose to recreate and then restart the containers without any downtime?

sffc
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2 Answers2

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Here’s a really simple solution we found for zero downtime, blue–green style deploys with just docker-compose and nginx: https://engineering.tines.com/blog/simple-zero-downtime-deploys.

Turns out, a well-placed bash script is all you need here! This method saved us adding other dependencies to our stack. Here's the central piece:

reload_nginx() {  
  docker exec nginx /usr/sbin/nginx -s reload  
}

zero_downtime_deploy() {  
  service_name=tines-app  
  old_container_id=$(docker ps -f name=$service_name -q | tail -n1)

  # bring a new container online, running new code  
  # (nginx continues routing to the old container only)  
  docker-compose up -d --no-deps --scale $service_name=2 --no-recreate $service_name

  # wait for new container to be available  
  new_container_id=$(docker ps -f name=$service_name -q | head -n1)
  new_container_ip=$(docker inspect -f '{{range.NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $new_container_id)
  curl --silent --include --retry-connrefused --retry 30 --retry-delay 1 --fail http://$new_container_ip:3000/ || exit 1

  # start routing requests to the new container (as well as the old)  
  reload_nginx

  # take the old container offline  
  docker stop $old_container_id
  docker rm $old_container_id

  docker-compose up -d --no-deps --scale $service_name=1 --no-recreate $service_name

  # stop routing requests to the old container  
  reload_nginx  
}

Hope this can help others.

Stephen O'Brien
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docker-compose up by itself does not support any way of deploying with zero downtime.

https://docs.docker.com/compose/reference/up/

You'll need to implement your own blue/green deployment or have a look at kubernetes's rolling update: https://kubernetes.io/docs/tutorials/kubernetes-basics/update/update-intro/

invad0r
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