Docker Basics

Study Notes

Docker is a software that helps make the software development cycle more efficient by solving practical challenges.
A lot of different objects work together to run an application inside Docker.
An application requires objects such as Docker Images for the application code, Docker Containers to run the application, and Docker Registries to save and download Docker Images.
Docker container is the place where the docker runs an image. You can think of it in this way as well for simplicity: Images become containers when they run on Docker Engine.
A Docker image is a lightweight, executable package that consists of everything needed to run an application: code, libraries, third-party dependencies, environment variables, and configurations.
A Dockerfile is a document that consists of all the commands a user wants to call on the command line to build an image.
To be able to run the Docker Engine, you’ll need to have a supported version of CentOS. The latest version is recommended.
In order to install the engine, we’ll first set up the docker repository and then use the repository to install the docker engine.
The engine has been installed, but it hasn’t been started yet. Let’s start it.
Let’s verify if the engine is able to pull an image by running the below command.
Let’s verify if the engine is able to run a container by running the below command.