Introduction to Docker Containers

150 150 DevGate

Author: Qamar Khurshid,

Docker containers are a popular and efficient way to package and deploy applications, and the Docker command-line interface (CLI) provides a convenient way to manage and deploy containers. In this blog post, we’ll take a closer look at the Docker CLI and some of its basic commands, and explain how to use them to deploy Docker containers.

The Docker CLI is a tool that allows users to interact with Docker from the command line, and provides a wide range of commands for managing and deploying Docker containers. Some of the most commonly used Docker CLI commands include:

docker run: This command is used to run a Docker container. It takes a Docker image as input, and creates a new container based on that image.

docker ps: This command lists all running Docker containers on the host machine.

docker stop: This command stops a running Docker container. It takes the container’s name or ID as input.

docker rm: This command removes a stopped Docker container. It takes the container’s name or ID as input.

docker build: This command is used to build a Docker image from a Dockerfile. A Dockerfile is a text file that contains the instructions for building a Docker image.

To deploy a Docker container, you first need to create a Docker image. This can be done using the docker build command, which takes a Dockerfile as input and produces a Docker image as output. Once you have a Docker image, you can use the docker run command to create a new container based on that image, and then start the container using the docker start command.

For example, let’s say you have a simple Node.js application that you want to deploy as a Docker container. First, you would create a Dockerfile that specifies the instructions for building a Docker image for the application. This might look something like this:

Next, you can use the docker build command to build a Docker image from the Dockerfile:

docker build -t my-node-app .

This will create a Docker image named my-node-app based on the instructions in the Dockerfile. Once you have the Docker image, you can use the docker run command to create and start a Docker container based on the image:

docker run -d -p 3000:3000 –name my-node-app my-node-app

This will create a new Docker container named my-node-app, and start it in detached mode (-d). It will also map port 3000 on the host machine to port 3000 on the container (-p 3000:3000), which will allow you to access the application from the host machine.

To verify that the container is running, you can use the docker ps command, which will list all running Docker containers on the host machine:

docker ps

This will show the running Docker containers, along with their names