Understanding containers

Containers have become popular because they allow code to be packaged to easily run on a developer’s workstation and a multi-node cluster in the cloud. Think of a standard shipping container. It’s designed to hold a variety of goods and can be transported seamlessly by trucks, ships, and trains. Similarly, a software container holds an application and its supporting files, allowing it to run reliably on different computers (servers, laptops, the cloud, etc.). A container has everything your application needs to run:

• The code: The actual instructions that make your application work
• Runtime environment: The software that understands and executes your code (such as Python, Java, or Node.js)
• Libraries and tools: The helpers your code relies on to do specific tasks
• Settings: The configurations that tell your application how to behave

Container portability makes it possible for an application to go from a developer’...