How to Install Docker CE on Linux Mint 21 or 20

This guide will demonstrate how to install Docker CE on Linux Mint 21 or 20, a process essential for leveraging Docker’s robust capabilities on your Linux system.

Docker CE stands as a powerful platform for developing, shipping and running applications efficiently. Known for its ease of use and versatility, Docker CE facilitates containerization, allowing you to encapsulate applications in containers, thereby improving portability and consistency across various environments.

Key Features of Docker CE:

• Container Management: Simplifies the creation, deployment, and scaling of applications.
• Portability: Ensures applications run consistently across different environments.
• Microservices Architecture: Ideal for building and managing microservices-based applications.
• Version Control for Containers: Tracks changes in containers, enhancing collaboration and development.
• Resource Efficiency: Offers higher efficiency than traditional virtual machines, optimizing system resources.

Transitioning from the conceptual to the practical, the installation of Docker CE on Linux Mint involves a series of straightforward steps. This installation not only equips your system with Docker’s containerization capabilities but also sets the stage for a more streamlined and efficient development workflow. Let’s delve into the installation process, which will unlock the full potential of Docker CE on your Linux Mint environment.

Docker CE Pre-Installation Steps on Linux Mint 21 or 20

Skip this section if you do not have Docker from Linux Mint’s repository installed.

Step 1: Remove Previous Docker Instances on Linux Mint

Before installing Docker CE on Linux Mint, it’s crucial to clear any existing Docker versions. This step is necessary to avoid conflicts with the new installation. If Docker has never been installed on your system, you can skip this step.

To remove any existing Docker installations, execute:

sudo apt remove docker docker-engine docker.io containerd runc

This command ensures that any previous versions of Docker and its associated components are removed from your system. If there are no Docker instances to remove, you’ll receive a message indicating so.

Keep in mind, uninstalling Docker doesn’t delete Docker images, containers, volumes, or networks, which are stored in /var/lib/docker/. To completely remove all Docker data and start with a clean slate, use the following commands:

sudo rm -rf /var/lib/docker
sudo rm -rf /var/lib/containerd

Executing these commands deletes all Docker-related data, prepping your system for a fresh Docker CE installation.

Step 2: Update Linux Mint Packages Before Docker Installation

After clearing old Docker versions, the next step is to update your Linux Mint system. This ensures that all your system packages are current, reducing the risk of conflicts and security vulnerabilities.

Run the following command to update your package lists and upgrade any outdated packages:

sudo apt update && sudo apt upgrade

The sudo apt update command refreshes your package index, ensuring you have the latest information on available packages. Following this, sudo apt upgrade updates all installed packages to their latest versions.

Import Docker CE APT Repository on Linux Mint 21 or 20

Step 1: Install Initial Packages For Docker CE on Linux Mint

To prepare for Docker CE installation, your Linux Mint system might require additional packages. These packages are critical for accessing and verifying Docker’s repository. To install them, execute:

sudo apt install ca-certificates curl gnupg lsb-release dirmngr software-properties-common apt-transport-https

This command uses the apt package manager to install several tools. ca-certificates helps with certificate verification, curl is used for data transfer, gnupg manages encryption keys, and other tools ensure a smooth process.

Step 2: Add Docker CE GPG Key on Linux Mint

The next step is to import the Docker GPG key, which is vital for ensuring the integrity of Docker packages. The GPG key acts as a digital signature, confirming the authenticity of downloaded content.

To download and add the GPG key, use these commands:

wget -q https://download.docker.com/linux/ubuntu/gpg -O- | sudo gpg --dearmor -o /usr/share/keyrings/docker.gpg

Here, curl fetches the GPG key from Docker’s repository. The gpg --dearmor command then processes the key into a binary format required by the apt package manager.

Step 3: Add Docker CE APT Repository on Linux Mint

With the GPG key added, the next step is to add the Docker repository to your Linux Mint system. This repository contains the Docker packages needed for installation.

Execute the following command to add the Docker repository:

Ensure to import the correct Docker Community Edition APT repository for your version of Linux Mint.

Docker CE APT Repository For Linux Mint 21

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu jammy stable" | sudo tee /etc/apt/sources.list.d/docker.list

Docker CE APT Repository For Linux Mint 20

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu focal stable" | sudo tee /etc/apt/sources.list.d/docker.list

These command constructs the repository entry, specifying your system’s architecture and linking to the GPG key for package verification. It adds the repository to your system’s software sources, enabling you to install Docker CE from a trusted source.

Install Docker on Linux Mint 21 or 20

Step 1: Update Linux Mint APT Cache After Docker CE Repository Import

After adding the Docker repository, it’s essential to update your system’s repository information. This step ensures your system recognizes the newly added Docker repository.

To update the repository, run:

sudo apt update

This command refreshes the package lists on your system, incorporating the latest versions of packages and their dependencies. It’s a critical step for maintaining a current and secure system.

Step 2: Install Docker on Linux Mint 21 or 20 via APT Command

With your repository information up to date, you’re ready to install Docker. The following command installs Docker along with several essential plugins:

sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Here, docker-ce is the Docker Community Edition, docker-ce-cli is Docker’s command-line interface, containerd.io provides the container runtime, and the docker-buildx-plugin and docker-compose-plugin are valuable tools for building images and orchestrating multi-container Docker applications.

Step 3: Verify Docker CE Installation on Linux Mint

Once Docker is installed, it’s crucial to verify the installation. Run a test Docker image to confirm Docker is operational:

sudo docker run hello-world

This command fetches the hello-world image from Docker’s repository, creates a container, and runs it. The output should display a welcome message, indicating that Docker is correctly installed and functional on your Linux Mint system.

Step 4: Running Docker as a Non-Root User on Linux Mint

For enhanced security, configure Docker to run under a non-root user. This mitigates risks associated with root-level access. Detailed instructions for this configuration will follow in a subsequent section.

Docker Troubleshooting Tip

If issues arise while working with Docker, a system reboot can often resolve path generation and other common problems.

To restart your Linux Mint system, use:

reboot

A reboot can help clear up transient issues and ensure your Docker environment is functioning optimally.

Managing Docker via Systemd on Linux Mint 21 or 20

Starting the Docker Service on Linux Mint via systemd

To use Docker, the Docker service must be active on your Linux Mint system. Start the service using systemd with this command:

sudo systemctl start docker.service

Executing this command initiates the Docker service and configures it for automatic launch at system boot, ensuring Docker is ready after each startup.

Stopping the Docker Service on Linux Mint via systemd

There may be scenarios where stopping the Docker service is necessary. Systemd allows you to do this easily:

sudo systemctl stop docker.service

This command stops the Docker service, preventing it from starting automatically on the next boot.

Restarting the Docker Service on Linux Mint via systemd

For troubleshooting or applying new configurations, restarting the Docker service is often required. Use this systemd command:

sudo systemctl restart docker.service

This restarts the Docker service, effectively reapplying the latest settings and changes.

Checking Docker Service Status on Linux Mint via systemd

To view the current status of the Docker service, whether running, stopped, or inactive, use this command:

sudo systemctl status docker.service

This provides detailed information about the Docker service’s operational state.

Enabling Docker Service on Linux Mint System Boot via systemd

For Docker to start automatically at system boot, enable it using systemd:

sudo systemctl enable docker.service

This command configures Docker to automatically initiate at each system boot.

Disabling Docker Service on Linux Mint System Boot via systemd

To prevent Docker from automatically starting at system boot, systemd can be used to disable it:

sudo systemctl disable docker.service

This alters Docker’s settings, stopping it from auto-launching at boot.

Step 1: Run Docker as a Non-Root User

Running Docker as a non-root user is recommended to mitigate security risks and prevent accidental system alterations. Set up a dedicated user account for managing Docker:

sudo useradd -m dockeruser
sudo usermod -aG docker dockeruser

These commands create a new user dockeruser and add this user to the Docker group, allowing the execution of Docker commands without root privileges.

To add your current user to the Docker group, substitute dockeruser with your username.

For example, for a user joshua:

sudo usermod -aG docker joshua

After adding the user to the Docker group, log out and log back in for the changes to take effect. Do not forget to reboot for the new changes to be activated:

sudo reboot

Verify the user’s Docker command permissions with:

docker ps

This command should list running Docker containers, confirming successful Docker setup under the non-root user.

Step 2: Modify Default Docker Logging Driver on Linux Mint

Docker defaults to JSON file format for logging events. However, you can change this to other formats or even configure Docker to forward logs to a remote logging system.

To change the logging driver, create a daemon.json file in /etc/docker/. Use a text editor like nano:

sudo nano /etc/docker/daemon.json

In the editor, input the following:

{
  "log-driver": "syslog",
  "log-opts": {
    "syslog-address": "tcp://logs.example.com:514",
    "syslog-facility": "daemon",
    "tag": "{{.Name}}"
  }
}

This configuration uses the syslog driver and forwards logs to a remote syslog server. Replace logs.example.com with your syslog server’s address.

After updating the configuration, restart the Docker daemon to apply the new settings:

sudo systemctl restart docker.service

Remember, any changes to the daemon.json file require restarting the Docker daemon for the modifications to take effect.

Docker Command Examples on Linux Mint 21 or 20

Fundamentals of Docker Commands on Linux Mint

Mastering Docker’s command line interface (CLI) is key to effectively managing containers, images, networks, and volumes. Here’s an overview of frequently used Docker commands:

• docker run: Starts a new container from an image.
• docker ps: Shows all active containers.
• docker images: Lists available local images.
• docker build: Builds a new image from a Dockerfile.
• docker stop: Stops a running container.
• docker rm: Removes a container.
• docker rmi: Deletes an image.
• docker network: Manages Docker networks.
• docker volume: Handles Docker volumes.

Each command offers options to tailor its functionality to specific requirements.

The docker run Command

Use docker run to initiate a container from an image. For example, to start a container from the latest Ubuntu image with an interactive shell:

docker run -it ubuntu:latest /bin/bash

The docker ps Command

docker ps lists all active containers, providing details like container ID, image used, and status:

docker ps

The docker images Command

docker images shows all locally stored Docker images, displaying their ID, repository, and tag:

docker images

The docker build Command

docker build constructs a new image from a Dockerfile. For example, to build an image named ‘customimage’ using a Dockerfile in the current directory:

docker build -t customimage:latest .

The docker stop Command

docker stop gracefully shuts down a running container. Specify the container ID, for instance:

docker stop container123

The docker rm Command

Remove a Docker container with docker rm, indicating the container ID:

docker rm container123

The docker rmi Command

To delete Docker images, use docker rmi. Identify the image by its ID:

docker rmi image12345

The docker network Command

docker network is used for network-related tasks like creating, listing, or removing networks. To create a network named ‘network1’:

docker network create network1

The docker volume Command

Manage Docker volumes with docker volume. To create a volume named ‘volume1’:

docker volume create volume1

Navigating Docker Container Management on Linux Mint 21 or 20

Core Commands for Docker Container Management with Linux Mint

Mastering Docker’s command-line interface is key to effective container management. Key commands include:

docker ps

Lists all active containers, displaying their image, status, and ID.

docker ps

docker stop

Stops an active container. Append the container’s ID or name.

docker stop unique_container_id

docker rm

Removes a container, also using the container’s ID or name.

docker rm unique_container_id

Removing a container with docker rm discards any unsaved changes. To preserve modifications, utilize the docker commit command.

Retaining Container Changes using docker commit

Creating a new image with saved changes in a Docker container is achieved using docker commit.

Starting a Container and Making Modifications

Start a new container from a base image and modify it:

docker run -it --name custom_container ubuntu:latest /bin/bash

Perform tasks like editing files or installing software within this container.

Saving Changes with docker commit

After making changes, use docker commit to create a new image encapsulating these modifications:

docker commit custom_container mycustomimage:latest

This creates a new image mycustomimage with the alterations made in custom_container. Use this image for new containers with the updated setup.

Remember, docker commit only saves filesystem changes, not modifications to networking and storage. For comprehensive changes, explore additional Docker commands like docker network and docker volume.

Conclusion

Alright, we’ve journeyed through the essentials of Docker on Linux Mint, from installing and configuring to managing containers like a pro. Remember, keeping Docker updated and running as a non-root user is key for security. Don’t forget to use docker commit wisely to save those crucial changes. As you dive deeper, experiment and explore – Docker’s quite the toolbox! Stay curious, keep tweaking, and you’ll master the art of container management in no time.