Introduction to containers

In the world of software development (as well as in this course), one of the persistent challenges is ensuring that code compiles and runs consistently across different platforms and environments. Variations in operating systems, configurations, libraries, and dependencies can lead to platform-specific issues that disrupt the portability and reliability of code execution.

Containerization addresses these challenges by packaging applications and their dependencies into standardized units called containers. Managed by container platforms like Docker and Apptainer, containers encapsulate everything needed to run the software, including code, runtime, libraries, and system tools. This ensures that applications can execute consistently, regardless of where they are deployed, making them independent of the underlying host environment’s specifics.

Such agility and flexibility in application management drastically reduce the “it works on my machine” problem, streamline development workflows, facilitate seamless scaling, and enhance collaboration across diverse computing environments. Containerization has become a cornerstone technology in modern computational systems, providing a robust solution to cross-platform compatibility and efficiency. As such, it is a worthwhile skill to develop even outside of this course.

Understanding the distinction between containers and virtual machines (VMs)

You may already be somewhat familiar with the concept of virtual machines, which are emulations of physical computers that allow multiple operating systems to run on a single host machine through the use of virtualization technology. Virtual machines encapsulate an entire system, including the hardware layer, allowing robust isolation and resource allocation. However, this level of abstraction often comes with overhead in terms of system resources, which can impact efficiency.

In contrast, containerization provides a lightweight alternative by sharing the host operating system’s kernel rather than emulating hardware. Containers package applications and their dependencies in isolated environments without the additional resource demands associated with full hardware virtualization. For further reading material, many resources exist online - although Red Hat offers a concise introduction.