How to Work with Docker Containers Using the Docker CLI?

Docker containers are small and portable software packages. They have everything we need to run an application. This includes the code, the runtime, the libraries, and the system tools. We build them on the Docker platform. It helps us automate how we deploy applications inside these containers. Using Docker containers helps us keep things the same in different environments. It also helps us use resources better. Plus, it makes deploying and scaling applications easier.

In this article, we will show how to work well with Docker containers using the Docker CLI. We will start with the basics of Docker containers and why they are good. Then, we will guide you on how to install Docker and set up the CLI. After that, we will show how to create and run Docker containers from images. We will also give tips on how to manage containers that are running. We will talk about networking and volumes too. These are important for containers to talk to each other and keep data. Lastly, we will answer some common questions to help you understand Docker containers and the Docker CLI better.

  • How to Effectively Use Docker Containers with the Docker CLI?
  • What are Docker Containers and Why Use Them?
  • How to Install Docker and Set Up the CLI?
  • How to Create and Run Docker Containers from Images?
  • How to Manage Running Docker Containers?
  • How to Use Docker CLI Commands for Networking and Volumes?
  • Frequently Asked Questions

What are Docker Containers and Why Use Them?

Docker containers are small and independent packages. They have everything needed to run a software. This includes the code, runtime, libraries, and system tools. We build them using containerization. This technology lets applications run in separate environments. This separation makes sure the application works the same way no matter where we run it.

Key Features of Docker Containers:

  • Portability: We can run Docker containers on any system that supports Docker. This makes it easy to move applications between development, testing, and production environments.
  • Scalability: We can easily scale containers up or down to manage different loads.
  • Efficiency: Containers share the host system’s kernel. This helps them start quickly and use less resources than traditional virtual machines.
  • Isolation: Each container runs in its own space. This means applications do not mess with each other.

Why Use Docker Containers?

  • Consistency Across Environments: Containers make sure the application works the same way everywhere. This helps reduce the “it works on my machine” problem.
  • Simplified Dependency Management: All dependencies are packed inside the container. This solves problems with missing libraries or wrong versions.
  • Microservices Architecture: Docker containers help us build microservices. This lets teams develop, deploy, and scale applications on their own.
  • Rapid Deployment: We can build and deploy containers fast. This speeds up development cycles and supports continuous integration/continuous deployment (CI/CD) practices.

In summary, Docker containers are a strong way to package, share, and run applications in a consistent and efficient way. To learn more about Docker and its benefits, check out this article on the benefits of using Docker in development.

How to Install Docker and Set Up the CLI?

To work well with Docker containers using the Docker CLI, we first need to install Docker and set up the command-line interface (CLI). Here are the steps for installation on different operating systems.

Installing Docker on Various Operating Systems

On Windows

  1. Download Docker Desktop: Visit the Docker Desktop for Windows page.

  2. Run the Installer: Double-click the installer we downloaded and follow the wizard.

  3. Start Docker: After the installation, we can launch Docker Desktop from the Start menu.

  4. Enable WSL 2: Make sure that WSL 2 is enabled if we use Windows 10 or later.

  5. Verify Installation: Open Command Prompt or PowerShell and run:

    docker --version

On macOS

  1. Download Docker Desktop: Go to the Docker Desktop for Mac page.

  2. Install: Open the .dmg file we downloaded and drag Docker to the Applications folder.

  3. Run Docker: Start Docker from the Applications folder.

  4. Verify Installation: Open Terminal and run:

    docker --version

On Linux (Ubuntu)

  1. Update the Package Index:

    sudo apt-get update

  2. Install Required Packages:

    sudo apt-get install apt-transport-https ca-certificates curl software-properties-common

  3. Add Docker’s Official GPG Key:

    curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

  4. Set up the Stable Repository:

    sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

  5. Install Docker:

    sudo apt-get update
sudo apt-get install docker-ce

  6. Verify Installation:

    docker --version

Setting Up the Docker CLI

After we install Docker, we can set up the CLI for our user:

  1. Manage Docker as a Non-root User (Linux only):

    sudo usermod -aG docker $USER

    We need to log out and back in for changes to work.

  2. Check Docker Service:

    sudo systemctl start docker
sudo systemctl enable docker

  3. Test Docker Installation: We can run a test container:

    docker run hello-world

This command pulls a test image from Docker Hub and runs it in a container. This way, we make sure that our installation works well.

For more details on installing Docker on different operating systems, we can check this guide.

How to Create and Run Docker Containers from Images?

We can create and run Docker containers from images using the Docker CLI. Here is how we do it:

  1. Pull an Image: First, we use the docker pull command to get an image from Docker Hub or another container registry.

    docker pull <image-name>

    For example:

    docker pull ubuntu:latest

  2. Create a Container: Next, we use the docker create command to make a container from the image we pulled. The container will not start yet.

    docker create --name <container-name> <image-name>

    For example:

    docker create --name my-ubuntu ubuntu:latest

  3. Run a Container: Now, we can run a container with the docker run command. This command creates and starts the container in one step. We can also set options like detached mode and port mapping.

    docker run -d --name <container-name> -p <host-port>:<container-port> <image-name>

    For example:

    docker run -d --name my-ubuntu -p 8080:80 ubuntu:latest

    Here, -d runs the container in detached mode. The -p option maps ports from our host to the container.

  4. Run Interactively: If we want to run a container interactively, we use the -it flags.

    docker run -it <image-name> /bin/bash

    For example:

    docker run -it ubuntu:latest /bin/bash

  5. Check Running Containers: We can see all running containers by using the docker ps command.

    docker ps

  6. Inspect a Container: Lastly, we can get detailed information about a specific container by using the docker inspect command.

    docker inspect <container-id or container-name>

    For example:

    docker inspect my-ubuntu

By following these steps, we can create and run Docker containers from images using the Docker CLI. For more details on Docker images and how they work, we can check this link what are Docker images and how do they work.

How to Manage Running Docker Containers?

We can manage running Docker containers by using the Docker command-line interface (CLI). We can do many things like listing containers, stopping and starting them, and removing them when we need to. Here are some important commands and how to use them.

List Running Containers

To see all containers that are currently running, we use this command:

docker ps

If we want to see all containers, both running and stopped, we add the -a option:

docker ps -a

Stopping Containers

If we want to stop a running container, we use the docker stop command and then add the container ID or name:

docker stop <container_id_or_name>

Starting Containers

To start a container that is stopped, we use the docker start command:

docker start <container_id_or_name>

Restarting Containers

If we want to restart a running or stopped container, we use the docker restart command:

docker restart <container_id_or_name>

Pausing and Unpausing Containers

To pause a running container for a short time, we can use:

docker pause <container_id_or_name>

To unpause it, we use:

docker unpause <container_id_or_name>

Removing Containers

If we want to remove a stopped container, we use the docker rm command:

docker rm <container_id_or_name>

If we need to remove a running container, we must stop it first. Or we can use the -f option to remove it forcefully:

docker rm -f <container_id_or_name>

Inspecting Containers

To see details about a specific container, we use the docker inspect command:

docker inspect <container_id_or_name>

This command gives us important information like configuration, state, and networking settings.

Viewing Container Logs

If we want to see logs for a specific container, we use:

docker logs <container_id_or_name>

We can also follow the logs in real time by adding the -f option:

docker logs -f <container_id_or_name>

Executing Commands in Running Containers

To run a command inside a running container, we use the docker exec command:

docker exec -it <container_id_or_name> <command>

For example, to open a bash shell in a container, we can use:

docker exec -it <container_id_or_name> /bin/bash

These commands and tips help us manage running Docker containers using the Docker CLI. For more details on Docker container management, we can check this detailed article.

How to Use Docker CLI Commands for Networking and Volumes?

When we work with Docker containers, we need to know how to manage networking and volumes using the Docker Command Line Interface (CLI). This section will show the main commands and tips to use networking and volumes in our Docker setup.

Docker Networking Commands

Docker gives us different networking options. These help containers talk to each other. Here are some important commands for managing Docker networks:

  1. Create a Network:

    docker network create my_network

  2. List Networks:

    docker network ls

  3. Inspect a Network:

    docker network inspect my_network

  4. Connect a Container to a Network:

    docker network connect my_network my_container

  5. Disconnect a Container from a Network:

    docker network disconnect my_network my_container

  6. Remove a Network:

    docker network rm my_network

Docker Volumes Commands

Volumes are important for keeping data safe in Docker containers. Here’s how we can manage volumes using the Docker CLI:

  1. Create a Volume:

    docker volume create my_volume

  2. List Volumes:

    docker volume ls

  3. Inspect a Volume:

    docker volume inspect my_volume

  4. Remove a Volume:

    docker volume rm my_volume

  5. Mount a Volume to a Container:

    docker run -d -v my_volume:/data my_image

  6. Bind Mount a Host Directory to a Container:

    docker run -d -v /host/path:/container/path my_image

  7. Backup a Volume:

    docker run --rm -v my_volume:/volume -v /host/backup:/backup busybox cp -a /volume/. /backup/

  8. Restore a Volume:

    docker run --rm -v my_volume:/volume -v /host/backup:/backup busybox cp -a /backup/. /volume/

When we understand these Docker CLI commands for networking and volumes, we can manage how our Docker containers connect and keep their data safe. For more details about Docker networking, we can check what are Docker networks and why are they necessary. And for volumes, we can look at what are Docker volumes and how do they work.

Frequently Asked Questions

1. What are Docker containers and how do they differ from virtual machines?

Docker containers are light and portable. They let us run applications separately from each other. Virtual machines are different. They come with a full operating system. Docker containers share the main OS kernel. This makes them use less resources. If we want to know more about this, we can check how Docker differs from virtual machines.

2. How do I install Docker and set up the Docker CLI?

To install Docker and set up the Docker CLI, we need to follow some steps. These steps depend on the operating system we use. Docker gives official guides for Windows, macOS, and many Linux versions. If we want to see the detailed steps, we can visit how to install Docker on different operating systems.

3. How can I create and run Docker containers from images?

Creating and running Docker containers from images is easy with the Docker CLI. We can use the docker run command and then the image name to start a container. This command creates and runs the container. It lets us run applications without problems. For example, we can use docker run -d myimage to run a container in detached mode.

4. What commands can I use to manage running Docker containers?

We can manage running Docker containers with several commands. We can use docker ps to see all running containers. To stop a container, we can use docker stop <container_id>. To remove a container, we can use docker rm <container_id>. These commands help us control our Docker container lifecycle. For more info on managing containers, we can check how to list and inspect Docker images.

5. How do Docker volumes work for data persistence?

Docker volumes are important for keeping data safe that Docker containers create or use. With volumes, we can store data outside of the container’s filesystem. This way, the data stays even after we remove the container. We can create a volume with docker volume create myvolume. Then we can use it in a container with -v myvolume:/path/in/container. If we want to learn more about volumes, we can look at what are Docker volumes and how do they work.