What tasks can LXC solve, and which are better suited for Docker?

LXC (Linux Containers) provides lightweight virtualization at the operating system level, allowing multiple isolated Linux instances to run on a single host. LXC manages kernel resources (namespaces, cgroups), creating virtual environments that appear as full-fledged OS.

Docker is based on LXC/runC but focuses on packaging and running applications in isolated containers. It adds layers of abstraction on top of basic virtualization: Dockerfile, images, registries, orchestration.

Tasks that LXC can solve:

• Server consolidation: Running multiple virtual servers with different distributions or OS versions on a single physical host.
• OS-level service isolation: Creating isolated environments for various system services or users with separate file systems, network configurations, and processes, similar to VMs but with less overhead.
• Testing and development in isolated environments: Providing development teams with isolated "sandboxes" with full OS instances for testing compatibility with different distributions or configurations.
• Running "traditional" applications: Suitable for applications requiring closer integration with the OS or having complex structures with multiple dependent processes, not intended for microservices architecture.

Tasks better suited for Docker:

• Packaging and delivering applications: Creating portable, self-sufficient artifacts (images) containing the application and all its dependencies for easy deployment in any environment supporting Docker.
• Microservices architecture: Ideal for breaking down large applications into independent, loosely coupled services, each running in a separate container.
• Continuous integration/delivery (CI/CD): Integrating containers into build, testing, and deployment pipelines to accelerate and standardize the process.
• Container orchestration: Using tools like Docker Swarm or Kubernetes for automatic deployment, scaling, and management of many containers.
• Isolating individual applications: Creating isolated environments for running specific applications or sets of related applications, minimizing dependency conflicts.
• Application development and testing: Providing developers with lightweight, reproducible environments for development and local testing without installing all dependencies on the host system.

Comparison of main characteristics:

Characteristic	LXC	Docker
Focus	OS-level isolation / Virtualization	Packaging and running applications
Images	OS-level / Filesystem snapshots	Multi-layered, application-level
Management	Lower-level	Higher-level, with CLI and API
Portability	Less (depends on kernel and FS)	Greater (standardized images)
Overhead	Slightly higher (closer to VMs)	Slightly lower (application focus)
Application	Virtual servers, service isolation	Microservices, CI/CD, deployment

Docker is built on the basic mechanisms provided by LXC (or other implementations like runC). LXC provides the foundation for OS-level containerization, while Docker adds a meta-layer for managing the lifecycle of applications in containers. The choice between them depends on the specific task: if lightweight full OS virtualization is needed, LXC may be suitable. If the goal is packaging, deployment, and orchestration of individual applications or microservices, Docker is more efficient.