how to get docker-compose to use the latest image from repository

Question

I don't know what I'm doing wrong, but I simply cannot get docker-compose up to use the latest image from our registry without first removing the old containers from the system completely. It looks like compose is using the previously started image even though docker-compose pull has fetched a newer image.

I looked at How to get docker-compose to always re-create containers from fresh images? which seemed to be similar to my issue, but none of the provided solutions there work for me, since I'm looking for a solution I can use on the production server and there I don't want to be removing all containers before starting them again (possible data loss?). I would like for compose only to detect the new version of the changed images, pull them and then restart the services with those new images.

I created a simple test project for this in which the only goal is to get a version nr to increase on each new build. The version nr is displayed if I browse to the nginx server that is created (this works as expected locally).

docker version: 1.11.2 docker-compose version: 1.7.1 OS: tested on both CentOS 7 and OS X 10.10 using docker-toolbox

My docker-compose.yml:

version: '2'
services:
  application:
    image: ourprivate.docker.reg:5000/ourcompany/buildchaintest:0.1.8-dev
    volumes:
      - /var/www/html
    tty: true

  nginx:
    build: nginx
    ports:
      - "80:80"
    volumes_from:
      - application
    volumes:
      - ./logs/nginx/:/var/log/nginx
  php:
    container_name: buildchaintest_php_1
    build: php-fpm
    expose:
      - "9000"
    volumes_from:
      - application
    volumes:
      - ./logs/php-fpm/:/var/www/logs

on our jenkins server I run the following to build and tag the image

cd $WORKSPACE && PROJECT_VERSION=$(cat VERSION)-dev
/usr/local/bin/docker-compose rm -f
/usr/local/bin/docker-compose build
docker tag ourprivate.docker.reg:5000/ourcompany/buildchaintest ourprivate.docker.reg:5000/ourcompany/buildchaintest:$PROJECT_VERSION
docker push ourprivate.docker.reg:5000/ourcompany/buildchaintest

this seems to be doing what it's supposed to be since I get a new version tag in our repository each time the build completes and the version nr has been bumped.

If I now run

docker-compose pull && docker-compose -f docker-compose.yml up -d

in a folder on my computer, where the contents is only the docker-compose.yml and the necessary Dockerfiles to build the nginx and php services, the output I get is not the latest version number as has been tagged in the registry or is shown in the docker-compose.yml (0.1.8), but the version before that, which is 0.1.7. However the output of the pull command would suggest that a new version of the image was fetched:

Pulling application (ourprivate.docker.reg:5000/ourcompany/buildchaintest:latest)...
latest: Pulling from ourcompany/buildchaintest
Digest: sha256:8f7a06203005ff932799fe89e7756cd21719cccb9099b7898af2399414bfe62a
Status: Downloaded newer image for docker.locotech.fi:5000/locotech/buildchaintest:0.1.8-dev

Only if I run

docker-compose stop && docker-compose rm -f

and then run the docker-compose up command do I get the new version to show up on screen as expected.

Is this intended behaviour of docker-compose? i.e. should I always do a docker-compose rm -f before running up again, even on production servers? Or am I doing something against the grain here, which is why it's not working?

The goal is to have our build process build and create tagged versions of the images needed in a docker-compose.yml, push those to our private registry and then for the "release to production-step" to simply copy the docker-compose.yml to the production server and run a docker-compose pull && docker-compose -f docker-compose.yml up -d for the new image to start in production. If anyone has tips on this or can point to a best practices tutorial for this kind of setup that would be much appreciated also.

Answer 1

in order to make sure, that you are using the latest version for your :latest tag from your registry (e.g. docker hub) you need to also pull the latest tag again. in case it changed, the diff will be downloaded and started when you docker-compose up again.

so this would be the way to go:

docker-compose stop
docker-compose rm -f
docker-compose pull   
docker-compose up -d

i glued this into an image that i run to start docker-compose and make sure images stay up-to-date: https://hub.docker.com/r/stephanlindauer/docker-compose-updater/