🐳 Install Docker Server

Docker is an open platform for developing, shipping, and running applications. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications.

Docker Architecture

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📥 Installation

Docker and Docker Compose can be installed easily on debian system using apt.

Install Docker server

# uninstall any old/conflicting Docker packages
sudo apt remove -y docker docker-engine docker.io containerd runc

# install requirements
sudo apt-get update
sudo apt install -y ca-certificates curl gnupg lsb-release

# add gpg key used to sign the docker repository
sudo mkdir -p /etc/apt/keyrings
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/debian/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

# add docker's official apt repository
echo \
  "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] \
  https://download.docker.com/linux/debian \
  $(lsb_release -cs) stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

# install docker
sudo apt-get update
sudo apt install -y docker-ce docker-ce-cli containerd.io

# check that docker and docker compose are installed
docker --version
docker compose

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⚙️ Configuration

Launching Docker commands as user instead of root

By default that Unix socket is owned by the user root and other users can only access it using sudo.
The Docker daemon always runs as the root user.

If you don’t want to preface the docker command with sudo, create a Unix group called docker and add users to it.
When the Docker daemon starts, it creates a Unix socket accessible by members of the docker group.

# add user to the docker group
sudo usermod -aG docker ${USER}
# log out and log back in so that your group membership is re-evaluated
sudo systemctl restart docker

Docker Log Rotation

By default, Docker does not enable log rotation.
As a result, container logs (*-json.log files) can grow very large over time, consuming gigabytes of disk space.
The following steps help you check log sizes, clean up existing logs, and enable automatic log rotation to prevent this problem.

Check Docker Containers' Log SizesClean Up Existing Container Logs

# list all container log files with their sizes
sudo find /var/lib/docker/containers -name "*-json.log" -exec du -sh {} +

# clean all container logs (they can be gigabytes in size)
sudo find /var/lib/docker/containers/ -name "*-json.log" -exec sudo truncate -s 0 {} \;

Note: This only clears logs: containers will continue running normally.

To prevent log files from growing indefinitely, configure log rotation via Docker's daemon.json file:

# create /etc/docker/daemon.json with log rotation settings
sudo tee /etc/docker/daemon.json > /dev/null <<EOF
{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10m",
    "max-file": "3"
  }
}
EOF

# restart docker for changes to take effect
sudo systemctl restart docker