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LXC (Linux Containers)

LXC is an operating-system-level virtualization method for running multiple isolated Linux systems (containers) on a control host using a single Linux kernel.

Containers vs. Virtual Machines​

Unlike KVM or VirtualBox, which virtualize hardware and run a completely separate kernel for each VM, LXC shares the host's kernel.

  • Pros: Containers are incredibly lightweight, start almost instantly, and have virtually zero performance overhead.
  • Cons: Containers must run the same OS family as the host (Linux on Linux). You cannot run a Windows container on a Linux host using LXC.

LXC vs. Docker​

While both use container technology (namespaces and cgroups), their philosophy differs:

  • Docker is designed for application containers. Each container usually runs a single process or service.
  • LXC / LXD is designed for system containers. They act and feel exactly like a lightweight virtual machine. You can SSH into them, they have their own init system (systemd), and you can run multiple services inside them.

LXD​

LXD (pronounced "lex-dee") is a next-generation system container manager. It acts as a wrapper around LXC, providing a REST API, a much friendlier command-line experience, and advanced features like snapshots, live migration, and storage pooling.

# Launch a new Ubuntu container using LXD
lxc launch ubuntu:22.04 my-container

# Get a shell inside the container
lxc exec my-container -- /bin/bash