Linuxcontainer

LinuxContainer is a family of operating-system-level virtualization technologies built into the Linux kernel that provide process isolation without requiring separate kernels. Containers run as isolated user-space instances on a single host, sharing the host kernel while maintaining separate file systems, process trees, and network namespaces. This approach differs from traditional virtual machines in that containers start quickly and incur less overhead because there is no separate kernel per container.

Originating with the Linux Containers (LXC) project in the late 2000s, LinuxContainer technologies gained broad adoption through Docker in 2013, which popularized container images and workflows. The LXD project later focused on system containers and improved management. The Open Container Initiative (OCI) standardizes container image formats and runtimes to promote interoperability among implementations such as runc, containerd, and CRI-O.

Key techniques include Linux namespaces for process isolation (PID, mount, UTS, IPC, network, user) and control groups (cgroups) for resource limits. Filesystem isolation commonly uses layered or union filesystems such as OverlayFS. Security enhancements may rely on AppArmor, SELinux, seccomp profiles, and user namespaces to limit privileges. Container runtimes execute the container processes and coordinate with container registries and image formats.

Common use cases include development environments, microservices architectures, continuous integration and delivery pipelines, and sandboxing for testing untrusted code. While containers provide lightweight and portable deployment, they share the kernel with the host, which can introduce risks if kernel vulnerabilities are exploited. Security best practices emphasize keeping the host kernel updated, applying least privilege, using non-root containers when possible, and employing orchestration tools for scalable management.

Common implementations include LXC, LXD, Docker, Kubernetes, OCI, containerd, and Podman.