Contents
Roadmap info from roadmap website
Docker Images
Docker images are lightweight, standalone, and executable packages that include everything needed to run an application. These images contain all necessary dependencies, libraries, runtime, system tools, and code to enable the application to run consistently across different environments.
Docker images are built and managed using Dockerfiles. A Dockerfile is a script that consists of instructions to create a Docker image, providing a step-by-step guide for setting up the application environment.
Working with Docker Images
Docker CLI provides several commands to manage and work with Docker images. Some essential commands include:
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docker image ls: List all available images on your local system. -
docker build: Build an image from a Dockerfile. -
docker image rm: Remove one or more images. -
docker pull: Pull an image from a registry (e.g., Docker Hub) to your local system. -
docker push: Push an image to a repository.
For example, to pull the official Ubuntu image from Docker Hub, you can run the following command:
docker pull ubuntu:latest
After pulling the image, you can create and run a container using that image with the docker run command:
docker run -it ubuntu:latest /bin/bash
This command creates a new container and starts an interactive session inside the container using the /bin/bash shell.
Sharing Images
Docker images can be shared and distributed using container registries, such as Docker Hub, Google Container Registry, or Amazon Elastic Container Registry (ECR). Once your images are pushed to a registry, others can easily access and utilize them.
To share your image, you first need to tag it with a proper naming format:
docker tag <image-id> <username>/<repository>:<tag>
Then, you can push the tagged image to a registry using:
docker push <username>/<repository>:<tag>
In conclusion, Docker images are a crucial part of the Docker ecosystem, allowing developers to package their applications, share them easily, and ensure consistency across different environments. By understanding Docker images and the commands to manage them, you can harness the power of containerization and enhance your development workflow.