What is the main role and benefits of using Docker containers in development and deployment?

Docker containers allow you to package an application together with all its dependencies and environment into a single isolated block. This provides:

• Portability: containers work the same on any system with Docker, regardless of OS and settings.
• Isolation: applications run in an isolated environment, reducing conflicts between dependencies.
• Fast deployment: containers start and stop very quickly.
• Scalability: easy to create and manage multiple instances of an application.

In development, this simplifies environment setup and testing, and in production — stability and ease of updates.