I recently had the need to run one of the Docker containers during the start of the Linux operating system. I decided to share with you the fastest, and the easiest way I have found so far to start any service in Linux – by using the systemd tool.

1. Preparing service configuration file

We start defining a new service by creating my-service.service file located in /etc/systemd/system directory:

sudo nano /etc/systemd/system/my-service.service

The following listing presents the simplest configuration, which is required to run the service. As you can see it is very simple. We put only the name of the service and commands responsible for to starting and stopping our service.

[Unit]
Description=My Service

[Service]
ExecStart=/path/to/my/service start
ExecStop=/path/to/my/service stop

[Install]
WantedBy=default.target

2. Enabling autostart and managing the newly created service

Simply placing the service configuration in the /etc/systemd/system directory it is not enough service to be launched at system startup. To achieve this effect, we have to activate the service. The following listings present some commands that are responsible for activating, deactivating, manual starting and stopping and checking the current status of the service.

Activation and deactivation of service run during system startup:

sudo systemctl enable my-service.service
sudo systemctl disable my-service.service

Starting and stopping of the service:

sudo systemctl start my-service.service
sudo systemctl stop my-service.service

Checking the status of the service

systemctl status my-service.service

3. Example: running docker container on Linux boot time

It is the time to discuss the theory presented above on a specific example. Let this be the launch of the Docker container named my-container-name. Let is assume that our service is called  my-docker-service. Based on the previously presented theory, create the file my-docker-service.service:

sudo nano /etc/systemd/system/my-docker-service.service

with following content:

[Unit]
Description=My Docker container
Requires=docker.service
After=docker.service

[Service]
Restart=always
ExecStart=/usr/bin/docker start -a my-container-name
ExecStop=/usr/bin/docker stop -t 10 my-container-name

[Install]
WantedBy=default.target

The last step is to activate the service run during system startup. To check the correctness of the configuration, we can manually start our service and check its status.

sudo systemctl enable my-docker-service.service
sudo systemctl start my-docker-service.service
sudo systemctl status my-docker-service.service