If you’re new to Docker, you may be wondering what it is and how to use it. Docker is a popular containerization platform that allows developers to package and run their applications in isolated environments. In this tutorial, we’ll cover the basics of Docker, including what it is, how to use it, and some commonly used Docker commands.
What is Docker?
Docker is a tool designed to make it easier to create, deploy, and run applications by using containers. Containers are lightweight, portable, and self-contained environments that can run anywhere, whether it’s on your laptop, a server, or in the cloud. Docker allows you to package your application and all its dependencies into a single container, which can be easily deployed to any environment that supports Docker.
How to Use Docker
To get started with Docker, you’ll need to install Docker on your machine. Once you’ve installed Docker, you can start using it to run containers. Here are the basic steps for using Docker:
Create a Dockerfile
A Dockerfile is a text file that contains instructions for building a Docker image. You can use a Dockerfile to specify the base image, copy files into the image, and run commands to install dependencies.
Build the Docker image
Once you have a Dockerfile, you can use the docker build command to build the Docker image. This will create a new image that contains your application and all its dependencies.
Run the Docker container
After you’ve built the Docker image, you can use the docker run command to start a container based on that image. This will launch your application inside a container.
Manage your Docker containers
You can use the docker ps command to see a list of running containers and the docker stop command to stop a running container.
Docker Commands
Here are some commonly used Docker commands that you’ll need to know:
docker build – Build a Docker image from a Dockerfile
The docker build command is used to build a Docker image from a Dockerfile. For example, if you have a Dockerfile in the current directory, you can build an image using the following command:
docker build -t myimage:latest .
This command will build an image named “myimage” with the tag “latest” from the Dockerfile in the current directory.
docker run – Run a Docker container
The docker run command is used to run a Docker container based on an image. For example, to run an instance of the “myimage” container we built in the previous step, you can use the following command:
docker run -it myimage:latest
This command will start a container based on the “myimage” image with the tag “latest” and open an interactive shell session in the container.
docker ps – List running Docker containers
The docker ps command is used to list all running Docker containers. For example, to list all running containers on your system, you can use the following command:
docker ps
This command will show you a list of all running containers along with their container IDs, image names, status, and other information.
docker stop – Stop a running Docker container
The docker stop command is used to stop a running Docker container. For example, to stop a container with the ID “abcd1234”, you can use the following command:
docker stop abcd1234
This command will stop the container with the ID “abcd1234”.
docker rm – Remove a Docker container
The docker rm command is used to remove a Docker container. For example, to remove a container with the ID “abcd1234”, you can use the following command:
docker rm abcd1234
This command will remove the container with the ID “abcd1234”.
docker images – List Docker images on your system
The docker images command is used to list all Docker images on your system. For example, to list all images on your system, you can use the following command:
docker images
This command will show you a list of all images on your system along with their repository, tag, and size.
docker rmi – Remove a Docker image
The docker rmi command is used to remove a Docker image. For example, to remove an image named “myimage” with the tag “latest”, you can use the following command:
docker rmi myimage:latest
This command will remove the “myimage” image with the tag “latest”.
docker exec – Run a command in a running Docker container
The docker exec command is used to run a command in a running Docker container. For example, to run the command “ls” in a container with the ID “abcd1234”, you can use the following command:
docker exec -it abcd1234 ls
This command will run the “ls” command inside the container with the ID “abcd1234” and show you a list of files and directories in the container’s current working directory.
Conclusion
In this tutorial, we’ve covered the basics of Docker, including what it is, how to use it, and some commonly used Docker commands. With Docker, you can easily create and deploy applications in isolated environments, making it a popular choice for developers who want to ensure their applications run consistently across different environments. Whether you’re just getting started with Docker or you’re looking to expand your knowledge, this tutorial should give you a good foundation to build on.