What is Docker's role in modern application development and deployment?

Docker plays a key role in modern application development and deployment, providing containerization — isolating applications and their dependencies in lightweight, portable containers.

Main advantages of Docker:

• Portability: containers work the same way in any environment — locally, on a server, or in the cloud.
• Isolation: applications and their dependencies do not conflict with others.
• Simplified deployment: applications can be quickly launched and scaled.
• Reproducibility of environment: developers and operators use the same images, reducing errors.

Example: a developer packages a Python application with necessary libraries into a Docker image, which is then deployed on a server without additional environment configuration.