Check If Docker Is Running – Linux Commands

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Checking if Docker is running on your Linux system is crucial for managing containerized applications effectively. Understanding how to verify the status of Docker can help mitigate issues with your Docker environment, especially during development and deployment.

In This Tutorial, You Will Learn:

  • How to check if the Docker service is active on Linux.
  • Common command-line utilities to verify Docker’s functionality.
  • Troubleshooting steps if Docker is not running correctly.
Check If Docker Is Running – Linux Commands
Check If Docker Is Running – Linux Commands

Software Requirements and Linux Command Line Conventions

Software Requirements and Linux Command Line Conventions
Category Requirements, Conventions, or Software Version Used
System Linux-based operating system (e.g., Ubuntu, CentOS, Debian)
Software Docker (latest version recommended)
Other Access to a terminal emulator
Conventions # – Requires commands to be executed with root privileges, either directly as root or using sudo.
$ – Requires commands to be executed as a regular non-privileged user.

Checking Docker Status

VERIFYING DOCKER STATUS
To check if Docker is running, you typically use the system’s service management tools and Docker command-line utilities.

Now, let’s explore the commands that allow you to confirm Docker’s status and the troubleshooting steps if you encounter any issues.

Example-by-Example Instructions

  1. Check Docker Service Status: Check if the Docker service is currently running. 
    $ sudo systemctl status docker

    This command provides detailed information about the Docker service, including whether it is active, inactive, or failed. Look for “active (running)” in the output.

    Check Docker Service Status with systemctl command
    Check Docker Service Status with systemctl command
  2. List Running Docker Containers: Check if any containers are currently running. 
    $ docker ps

    If Docker is running, this command will return a list of currently running containers. If there are no containers running, the output will be empty.

    List Running Docker Containers with docker ps command
    List Running Docker Containers with docker ps command
  3. Docker Info Command: Gather comprehensive information about the Docker installation. 
    $ docker info

    This command will show detailed information about the Docker installation, including server version, storage driver, and operational status. If the command fails, it may indicate that Docker is not running or is incorrectly configured.

    Docker Info Command reveals all information about your docker installation
    Docker Info Command reveals all information about your docker installation

TROUBLESHOOTING DOCKER
If you find that Docker is not running, consider the following troubleshooting steps: Check if Docker is installed properly, look for error messages in the output of systemctl status docker, or try starting the service with sudo systemctl start docker.

Conclusion

In this tutorial, you learned how to check if Docker is running using various command-line tools and what to do if it is not operational. Regular inspections of your Docker status can help prevent issues in container management and deployment.

Frequently Asked Questions (FAQ)

  1. What should I do if Docker is not running?

    If Docker is not running, use the command sudo systemctl start docker to start the service. You may also check logs using journalctl -u docker for any errors.

  2. Can I run Docker without sudo?

    By default, Docker commands often require root privileges. You can add your user to the ‘docker’ group to run commands without sudo.

  3. How do I ensure Docker starts on boot?

    To ensure Docker starts at boot, run the command sudo systemctl enable docker.

  4. How do I check Docker’s installed version?

    You can check the installed Docker version by running docker --version.

 

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