[Container] Docker Objects

Docker objects

• Dockerfile
  • A dockerfile is a editable text file that contains instructions needed to create an image in terminal.
  • The instructions docker provided:
    • FROM: Defines base image
    • RUN: Executes arbitrary commands
    • CMD: Defines default command for container execution
• Image
  • Use for createing Docker containers and Read-only template with instructions
  • Built using instructions in a Dockerfie; a new read-only image layer is creaed for each instruction
  • A writeable layer is added when an image layer is created for each instruction
  • Layers can be shared between images, which saves disk space and network bandwidth
  • image naming: hostname/repository:tag, dockr.io/ubuntu:18.04
• Container
  • arunnable instance of an image
  • Can be created, stopped, started or deleted using the Docker API or CLI
  • Can connect to multiple networks, attach storage, or create a new image based on its current state
  • Is well isolated from othe containers and its host machine
• Network: Networks are used for the isolated container communication
• Storage: Docker uses volumes and bind mounts to persist data even after a container stops
• Other objects Plugins Add-ons: Storage plugins provide the ability to connect to external stroage platforms