Let's now use Docker in production. Before we deploy our changes, we need to install Docker on our production server. Here, we'll only install Docker Engine instead of Docker Desktop, as we don't need the GUI.

All commands in production need to be prefixed with sudo. The build command has the following adjustments:

Use port 443 for HTTPS.
Our production container doesn't have access to the SSL certificate! We need to pass it a reference to the folder on our host file system that stores our SSL certificates. Docker calls these references volumes, hence the -v flag.

sudo docker run \
-d \
--name app \
--expose 443 \
-p 443:443 \
-v /etc/letsencrypt:/etc/letsencrypt \
-e SERVER_ENV=PROD \
app

Finally, we need to adjust our deploy script. It will now pull from Github, build a Docker image, stop the currently running container, start a container from the fresh image, and prune the old image.

msg "Pulling from GitHub"
git pull

msg "Building Docker image"
sudo docker build --tag app .

msg "Stopping Docker container"
sudo docker stop app
sudo docker rm app

msg "Starting Docker container"
sudo docker run \
-d \
--name app \
--expose 443 \
-p 443:443 \
-v /etc/letsencrypt:/etc/letsencrypt \
-e SERVER_ENV=PROD \
app

msg "Pruning stale Docker images"
sudo docker image prune -f

We have just deployed our first container! We now have a nicely isolated web server application that we can deploy locally and in production. At first glance, our changes have not achieved much - we still have a simple app we deploy with a single command. But this setup will start paying big dividends once the complexity of our app increases. In the next post, we will set up a container with SQL database.

#16 Docker in production