Lightweight virtualization using OS-level isolation
Containers are a lightweight form of virtualization that provides operating system-level isolation rather than hardware virtualization. Unlike virtual machines that emulate complete hardware environments, containers share the host operating system kernel while providing isolated user spaces. Key container technologies include: 1) Namespaces - Isolate processes, network, filesystem, and other resources. 2) Cgroups - Control and limit resource usage (CPU, memory, I/O). 3) Union filesystems - Allow efficient image layering and sharing. Popular container platforms include Docker (container runtime and packaging), Kubernetes (container orchestration), and containerd (industry-standard container runtime). Containers offer advantages over VMs including faster startup times, higher density, smaller footprint, and easier application packaging. However, they provide less isolation than VMs since all containers share the same host kernel. Container technology is fundamental to modern cloud-native application development, microservices architectures, and DevOps practices. Understanding containers is essential for developers, DevOps engineers, and cloud architects working with modern application deployment and orchestration.