If you're comparing LXC vs LXD, the easiest way to understand them is this: LXC is the technology that creates and runs Linux system containers, while LXD is a management platform built on top of LXC. LXD makes it easier to deploy, configure and manage containers by providing tools for networking, storage, images, snapshots and automation. In addition to Linux containers, modern LXD can also manage QEMU/KVM virtual machines.

If you prefer direct control and are comfortable configuring containers yourself, LXC is a good choice. If you want a simpler way to manage containers and virtual machines with built-in management features, LXD is the better option. The right choice ultimately depends on your workload, management preferences and deployment requirements.

What Is LXC?

LXC (Linux Containers) is an operating system-level virtualization technology that creates Linux system containers. Each container behaves like an independent Linux system with its own processes, users, network settings and file system, while sharing the host server's Linux kernel. Because containers share the same kernel instead of running separate operating systems, they start quickly and use system resources efficiently.

LXC uses Linux kernel features such as namespaces to isolate containers from one another and cgroups to control how much CPU, memory and other system resources each container can use. This combination provides isolated Linux environments while maintaining lightweight performance.

Advantages of LXC

✓ Lightweight container technology with minimal overhead.

✓ Starts Linux containers quickly.

✓ Uses CPU and memory efficiently by sharing the host kernel.

✓ Allows resource limits for CPU, memory and storage.

✓ Suitable for running multiple isolated Linux environments on one server.

Limitations of LXC

✓ Supports Linux-based operating systems only.

✓ All containers share the host's Linux kernel.

✓ Cannot run operating systems that require a different kernel, such as Windows.

✓ Does not provide the same level of isolation as a fully virtualized machine.

Common Use Cases

✓ Hosting Linux websites and applications.

✓ Creating development and testing environments.

✓ Running isolated services on a single Linux server.

✓ Learning and experimenting with Linux containers.

✓ Consolidating multiple lightweight Linux workloads on one server.

What Is LXD?

LXD is a system management platform designed to simplify the deployment, configuration and management of Linux containers and virtual machines. Instead of managing each instance manually, LXD provides a consistent way to create, start, stop, monitor and organize workloads from a single interface.

LXD includes built-in tools for managing images, storage, networking and instance settings. It also provides a command-line interface (CLI) and a REST API, making it suitable for both manual administration and automation. Whether you're managing a single server or multiple systems, LXD helps streamline day-to-day operations.

Advantages of LXD

✓ Simplifies the deployment and management of containers and virtual machines.

✓ Provides built-in image management for faster deployments.

✓ Supports reusable profiles to apply common configurations.

✓ Includes integrated networking and storage management.

✓ Offers a REST API and command-line interface for automation and remote administration.

✓ Supports snapshots to help protect and restore workloads.

Limitations of LXD

✓ Requires time to learn its management features and workflow.

✓ Advanced features may require additional planning and configuration.

✓ Some storage and networking capabilities depend on the underlying host environment.

Common Use Cases

✓ Deploying and managing Linux containers.

✓ Running virtual machines alongside containers.

✓ Creating development and testing environments.

✓ Automating infrastructure through the REST API.

✓ Managing multiple workloads from a centralized platform.

✓ Building scalable container and virtualization environments.

How LXC and LXD Work Together

Although LXC and LXD are closely related, they serve different roles. LXC provides the underlying container runtime, which is responsible for creating and running Linux system containers. LXD builds on top of LXC by adding a management layer that makes it easier to deploy, configure and manage containers.

When you create a Linux container through LXD, it uses LXC behind the scenes to launch and operate the container. LXD then handles tasks such as instance management, networking, storage, images, profiles and automation, allowing you to manage containers through a consistent interface instead of configuring everything manually.

In addition to Linux containers, LXD can also manage QEMU/KVM virtual machines from the same platform. This allows administrators to manage both containers and virtual machines using a single set of management tools.

It's also important to know that LXC can be used on its own if you prefer direct control over container creation and configuration. Using LXD is optional, but it provides additional management features that simplify day-to-day administration.

One point that frequently causes confusion is the lxc command. Although it shares the same name as the LXC project, the lxc command is the command-line client for LXD. It communicates with the LXD daemon to manage containers and virtual machines rather than interacting directly with the underlying LXC runtime.

How They Work Together

Key Takeaways

✓ LXC provides the technology that creates and runs Linux system containers.

✓ LXD uses LXC to deploy and manage Linux containers.

✓ LXD adds management features such as images, profiles, networking, storage and automation.

✓ LXD also manages QEMU/KVM virtual machines from the same platform.

✓ LXC can be used independently when direct container management is preferred.

✓ The lxc command is the command-line client used to communicate with the LXD daemon.

LXC vs LXD: Key Differences

Now that you understand what LXC and LXD are and how they work together, let's look at the key differences. While they are closely related, they serve different roles and offer different management experiences.

Technology Layer

LXC provides the core runtime for Linux system containers.

LXD provides a higher-level platform for managing containers and virtual machines.

Architecture

LXC focuses on creating and operating Linux containers.

LXD adds centralized tools for deploying, organizing and managing workloads.

Management Approach

LXC relies on direct container configuration and administration.

LXD provides a unified way to manage instances through its command-line interface and REST API.

Ease of Use

LXC is better suited to administrators who prefer direct control over container configuration.

LXD is designed to simplify everyday management tasks and reduce manual administration.

Automation

LXC can be automated using standard Linux scripting and administration tools.

LXD includes built-in automation through its REST API and management tools.

Virtual Machine Support

LXC manages Linux system containers only.

LXD can manage both Linux containers and QEMU/KVM virtual machines.

Quick Comparison

✓ LXC focuses on the core container runtime.

✓ LXD focuses on simplifying container and virtual machine management.

✓ LXC offers more direct control over container configuration.

✓ LXD provides built-in management and automation features.

✓ LXD supports managing both containers and virtual machines from one platform.

Resource Management and Performance

Both LXC and LXD are lightweight because Linux containers share the host system's Linux kernel instead of running separate operating systems. Containers created through LXD still use the LXC runtime, so their runtime performance is generally similar.

Resource Overhead

LXC has minimal overhead because it focuses only on running Linux containers.

LXD adds a small management overhead for services such as the LXD daemon, REST API, image management, networking and storage management. This overhead comes from the management platform, not from the containers themselves.

CPU and Memory

Both LXC and LXD allow administrators to assign CPU and memory limits to individual containers, helping ensure workloads share system resources efficiently.

Storage Performance

Storage performance depends primarily on the underlying storage hardware and backend rather than whether containers are managed directly with LXC or through LXD.

Startup Speed

Containers created with either LXC or LXD start quickly because they share the host Linux kernel instead of booting a separate operating system.

Performance Considerations

For most workloads, application performance is influenced more by server hardware, resource allocation and storage performance than by choosing LXC or LXD. The main difference is that LXD adds convenience and management features with only a small additional resource footprint.

Final Takes

✓ LXC has minimal overhead because it focuses on running Linux containers.

✓ LXD adds a small management overhead for features such as the daemon, API, networking and storage management.

✓ LXD containers still use the LXC runtime, so container runtime performance remains similar.

✓ CPU, memory and storage resources have a greater impact on performance than the choice of management platform.

Networking, Storage and Instance Management

Managing Linux containers involves more than simply creating them. Administrators also need to configure networking, storage and resource settings throughout the container's lifecycle. Both LXC and LXD support these tasks, but they approach day-to-day management differently.

Direct LXC

With LXC, administrators configure networking, storage and container settings directly on the host system. This approach provides greater control over the environment but typically requires more manual configuration and Linux administration knowledge.

✓ Configure container networking manually.

✓ Manage storage directly on the host system.

✓ Create and configure containers individually.

✓ Apply CPU, memory and other resource limits as needed.

✓ Suitable for administrators who prefer direct control over container management.

LXD

LXD provides built-in tools that simplify container administration by centralizing common management tasks. Instead of configuring each component manually, administrators can use integrated features to deploy and manage workloads more efficiently.

✓ Built-in network management with virtual networks and bridges.

✓ Managed storage pools and storage volumes.

✓ Image management for faster container deployment.

✓ Reusable profiles for applying common configurations.

✓ Projects to organize and separate workloads.

✓ Simplified instance lifecycle management, including creating, starting, stopping and deleting instances.

Key Takeaways

✓ LXC gives administrators direct control over networking, storage and container configuration.

✓ LXD simplifies daily administration through integrated management features.

✓ LXD makes it easier to deploy and organize multiple workloads using images, profiles and projects.

✓ The best choice depends on whether you prefer manual configuration or a centralized management experience.

Snapshots, Backups and Migration

Managing workloads also involves protecting data and moving instances between servers. Both LXC and LXD support snapshots, backups and migration, but the way these tasks are managed is different.

Snapshots

LXC

✓ Snapshot support depends on the underlying storage backend and configuration.

✓ Administrators typically create and manage snapshots using the available storage technology.

LXD

✓ Built-in snapshot management through the LXD interface.

✓ Snapshots can be created and restored using simple LXD commands or the REST API.

Backups

LXC

✓ Backup methods depend on the host system and storage configuration.

✓ Administrators typically use Linux backup tools or storage-level backups.

LXD

✓ Provides built-in instance export and backup capabilities.

✓ Makes it easier to create portable backups of containers and virtual machines.

Export and Import

LXC

✓ Export and import methods depend on the administrator's workflow.

✓ Usually performed with Linux tools or storage utilities.

LXD

✓ Includes built-in commands for exporting and importing instances.

✓ Simplifies moving workloads between compatible LXD environments.

Migration

LXC

✓ Container migration is managed manually or with external tools.

✓ The migration process depends on the deployment environment.

LXD

✓ Includes built-in migration capabilities for managed instances.

✓ Simplifies moving workloads between LXD servers when supported by the environment.

Recovery Planning

✓ LXC provides flexibility but relies more on administrator-managed backup and recovery procedures.

✓ LXD integrates snapshots, backups and migration into a single management platform, making recovery tasks easier to organize.

Key Takeaways

✓ LXC gives administrators more direct control over snapshots, backups and migration.

✓ LXD simplifies these tasks with built-in management features.

✓ Both support protecting and moving workloads, but LXD provides a more centralized management experience.

Security and Isolation

LXC and LXD use the same underlying Linux container security mechanisms because LXD relies on the LXC runtime for Linux containers. As a result, both use Linux namespaces, cgroups, Linux capabilities and security frameworks such as AppArmor or SELinux to help isolate workloads.

The main difference is that LXD adds centralized management and access controls, making it easier to manage security settings across multiple containers. If your workload requires stronger isolation or needs to run a different operating system, a virtual machine is generally the better choice because it runs its own guest kernel.

Key Takeaways

✓ LXC provides the core security and isolation features for Linux containers.

✓ LXD uses the same security mechanisms while adding centralized management and access controls.

✓ Both support AppArmor or SELinux, Linux capabilities and unprivileged containers.

✓ Virtual machines provide stronger isolation than Linux containers because they run their own guest kernel.

Operating System and Application Compatibility

LXC and LXD are designed primarily for Linux workloads, but the types of operating systems and applications they support depend on whether you are running containers or virtual machines.

Supported Linux Distributions

Both LXC and LXD support a wide range of Linux distributions, making them suitable for hosting applications, development environments and server workloads.

Shared Kernel Considerations

Linux containers share the host system's Linux kernel. As a result, containers must use a Linux-based operating system and cannot run a different kernel from the host.

Custom Kernels

Applications or workloads that require a custom Linux kernel are better suited to a virtual machine, where the guest operating system can run its own kernel independently of the host.

Windows Support

LXC containers cannot run Windows because they rely on the Linux kernel. However, LXD can manage QEMU/KVM virtual machines, allowing Windows and other operating systems to run as virtual machines.

Application Compatibility

Most Linux applications run normally inside LXC and LXD containers, provided they are compatible with the host kernel and do not require direct access to unsupported kernel features or hardware.

Docker Inside LXC/LXD

Docker can run inside LXC or LXD containers, but it depends on the container configuration, required kernel features and workload requirements. In some environments, additional configuration may be needed for full Docker functionality.

Key Takeaways

✓ Both LXC and LXD support a wide range of Linux distributions.

✓ Linux containers share the host kernel and cannot use a separate operating system kernel.

✓ Windows requires a virtual machine rather than a Linux container.

✓ Most Linux applications work normally inside containers.

✓ Docker can run inside LXC or LXD containers when the required configuration and kernel features are available.

LXC vs LXD: Which Should You Choose?

Choosing between LXC and LXD depends on how much control and management functionality you need. LXC is a good fit if you prefer working directly with Linux containers and configuring the environment yourself. LXD is better suited to users who want built-in management tools that simplify deploying and managing containers and virtual machines.