Docker Images and Registry

Components of Docker

• Docker will have two major components
  • Client
  • Daemon (Docker Engine)

What happens when we execute docker container run <image>

1. docker client will request the daemon
2. daemon will check for the image in the local registry
3. If not found in the local registry, then the image is downloaded from default registry to local registry (pull)
4. Using the image in the local registry, a container is created.

How to create Docker Image?

• Converting existing containers into images
• Exporting VMS to Docker Images
• Creating Docker Image using Dockerfile (Instruction based Approach)

Instruction Based Approach to be followed.

• In this we will make a note of deployment steps for the application to be run inside container.
• Learn mapping these steps to Dockerfile Instructions