How to restart a single container with docker-compose

I have a docker-compose.yml file that contains 4 containers: redis, postgres, api and worker.

During the development of the worker container, I often need to restart it in order to apply changes. Is there any good way to restart a single container (e.g. worker) without restarting the others?

Solution 1:

It is very simple: Use the command:

docker-compose restart worker

You can set the time to wait for stop before killing the container (in seconds)

docker-compose restart -t 30 worker

Note that this will restart the container but without rebuilding it. If you want to apply your changes and then restart, take a look at the other answers.

Solution 2:

The other answers to restarting a single node are on target, docker-compose restart worker. That will bounce that container, but not include any changes, even if you rebuilt it separately. You can manually stop, rm, create, and start, but there are much easier methods.

If you've updated your code, you can do the build and reload in a single step with:

docker-compose up --detach --build

That will first rebuild your images from any changed code, which is fast if there are no changes since the cache is reused. And then it only replaces the changed containers. If your downloaded images are stale, you can precede the above command with:

docker-compose pull

To download any changed images first (the containers won't be restarted until you run a command like the up above). Doing an initial stop is unnecessary.

And to only do this for a single service, follow the up or pull command with the services you want to specify, e.g.:

docker-compose up --detach --build worker

Here's a quick example of the first option, the Dockerfile is structured to keep the frequently changing parts of the code near the end. In fact the requirements are pulled in separately for the pip install since that file rarely changes. And since the nginx and redis containers were up-to-date, they weren't restarted. Total time for the entire process was under 6 seconds:

$ time docker-compose -f docker-compose.nginx-proxy.yml up --detach --build
Building counter
Step 1 : FROM python:2.7-alpine
 ---> fc479af56697
Step 2 : WORKDIR /app
 ---> Using cache
 ---> d04d0d6d98f1
Step 3 : ADD requirements.txt /app/requirements.txt
 ---> Using cache
 ---> 9c4e311f3f0c
Step 4 : RUN pip install -r requirements.txt
 ---> Using cache
 ---> 85b878795479
Step 5 : ADD . /app
 ---> 63e3d4e6b539
Removing intermediate container 9af53c35d8fe
Step 6 : EXPOSE 80
 ---> Running in a5b3d3f80cd4
 ---> 4ce3750610a9
Removing intermediate container a5b3d3f80cd4
Step 7 : CMD gunicorn app:app -b 0.0.0.0:80 --log-file - --access-logfile - --workers 4 --keep-alive 0
 ---> Running in 0d69957bda4c
 ---> d41ff1635cb7
Removing intermediate container 0d69957bda4c
Successfully built d41ff1635cb7
counter_nginx_1 is up-to-date
counter_redis_1 is up-to-date
Recreating counter_counter_1

real    0m5.959s
user    0m0.508s
sys     0m0.076s

Solution 3:

To restart a service with changes here are the steps that I performed:

docker-compose stop -t 1 worker
docker-compose build worker
docker-compose up --no-start worker
docker-compose start worker

Solution 4:

Following command

docker-compose restart worker

will just STOP and START the container. i.e without loading any changes from the docker-compose.xml

STOP is similar to hibernating in PC . Hence stop/start will not look for any changes made in configuration file . To reload from the recipe of container (docker-compose.xml) we need to remove and create the container (Similar analogy to rebooting the PC )

So commands will be as following

docker-compose stop worker       // go to hibernate
docker-compose rm worker        // shutdown the PC 
docker-compose create worker     // create the container from image and put it in hibernate

docker-compose start worker //bring container to life from hibernation