The Full Flow

Dockerfile → Image → Registry → Image → Container

Step 1: Developer Writes Dockerfile

• A simple text file with instructions
• Defines base OS / runtime, dependencies, and app start command
• Nothing runs at this stage

Step 2: Dockerfile Builds an Image

• Docker reads the Dockerfile and creates an Image
• Image is read-only, a single package containing everything needed to run the app
• Image is NOT running yet

Dockerfile → Image

Step 3: Image is Stored

• Stored locally on your system, or pushed to Docker Hub / registry
• Same image can be reused again and again

Step 4: Image Creates Container