Containerized

Containerized describes software packaged and run inside a container, an isolated, lightweight execution environment that shares the host operating system kernel but provides its own filesystem, networking, and process space. This approach is a form of operating-system-level virtualization designed to reduce overhead compared with full virtual machines.

Containers are built from images, which are layered filesystems that include the application and dependencies. An image is executed by a container runtime (such as runc or containerd) that adheres to standards like the Open Container Initiative (OCI). Images are stored in registries and pulled to hosts for execution.

Benefits include portability across development, testing, and production environments; consistent deployments; efficient use of resources; fast startup; and strong isolation for processes. Challenges include security considerations, complexity of multi-container deployments, and the need for orchestration tools in large-scale systems.

Containerization differs from traditional virtualization by sharing the host kernel rather than emulating hardware. It requires compatibility with the host kernel and careful configuration of namespaces, cgroups, and security profiles. Standards and ecosystems around containers, such as OCI specifications, help interoperability among runtimes and images.

Common technologies and practices include Docker as a widely used platform, container runtimes like containerd or CRI-O, orchestration systems such as Kubernetes and Docker Swarm, and build and deployment patterns using Dockerfiles and CI/CD pipelines. Use cases range from microservices and dev/test environments to scalable web apps and edge computing.