A virtualization software. That makes developing and deploying applications much easier.

• It packages application with all the necessary dependencies, configuration, system tools and runtime.
• Portable artifact, easily shared and distributed.

<aside> ✅ A standardized unit, that has everything the application needs to run.

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• Own isolated environment with all dependencies and configs. Standardizing process of running any service on any local environment, avoiding to install everything on your local machine.

<aside> 👉 Easy to run different versions of same app without any conflicts. Making deployment process more easy.

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• Docker contains the OS application layer, and all the services and apps are installed on top that layer.

  • Docker uses the OS Kernel of the host system, is the only part of the Operating System that Docker is not able to simulate.

    

• It is only able to virtualízate Linux based distros.

<aside> 💡 Go to the official Docker website and always refer to latest documentation guide in the official documentation.

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• Docker Images: Inmutable template that defines how a container will be realized. It contains all the information of the project, like the application, any services needed or the OS layer.
• Docker Containers: A running instance of an image. It actually starts the application that is in the Docker image.

<aside> ✅ You can run multiple containers from 1 image.

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• Docker Registries: A storage and distribution system for Docker Images. There you will find official images available from applications like Redis, Mongo, Postgres, etc…
  • Official images are maintained by the software authors or in collaboration with the Docker community.
  • These images are stored in Docker Hub.

• Docker images are versioned.
• Different versions are identified by tags called Images Tags.