Migrating from Proxmox to Incus: The Ultra-Lightweight, Kernel-Level Container Management Alternative

Introduction: The Evolution of Virtualization and the Rise of Incus

For years, Proxmox Virtual Environment (PVE) has been the undisputed champion of open-source virtualization platforms. By seamlessly combining Kernel-based Virtual Machines (KVM) for full virtualization with Linux Containers (LXC) for lightweight isolation, Proxmox provided enterprises with a robust, web-managed ecosystem. However, as infrastructure demands shift toward maximum efficiency, minimal resource overhead, and bare-metal performance, a growing number of system architects are re-evaluating their hypervisor stack.

Enter Incus. Born as a community-driven fork of LXD (initiated under the Linux Containers project following Canonical's licensing changes), Incus is rapidly gaining traction as a formidable alternative to Proxmox. Unlike traditional hypervisors that treat containerization as a secondary feature alongside heavy virtual machines, Incus elevates system containers (LXC) and lightweight virtual machines to first-class citizens. This blog post provides a comprehensive analysis of why and how organizations are replacing Proxmox with Incus to achieve an ultra-lightweight, kernel-level infrastructure.

Understanding the Architectural Shift: Type-1 Hypervisor vs. Kernel-Level Containers

To understand the benefits of Incus, we must first analyze the structural differences between traditional hypervisors and kernel-level container managers. Proxmox operates primarily as a Type-1 hypervisor environment. When you run a KVM-based virtual machine on Proxmox, the system must emulate an entire hardware stack—including virtual CPUs, memory management units, and PCI devices. This guarantees absolute isolation but introduces a noticeable hardware tax.

Incus, conversely, focuses heavily on system containers. Unlike application containers (such as Docker, which typically run a single process), system containers behave exactly like full virtual machines. They run a complete init system (like systemd), have their own crontab, SSH access, and network interfaces, but they share the host operating system's kernel.

"System containers offer the operational look and feel of a virtual machine, but with the performance, density, and speed of a bare-metal container."

By operating directly at the kernel level using Linux namespaces, cgroups, and LSMs (Linux Security Modules), Incus eliminates the hypervisor translation layer. This architectural efficiency results in near-zero CPU and memory overhead.

Key Reasons to Replace Proxmox with Incus

While Proxmox is an excellent, feature-rich platform, specific operational use cases make Incus a superior choice for modern data centers. Below are the primary drivers for migration:

1. Radical Resource Efficiency and Density

Because Incus containers share the host kernel, they do not require a pre-allocated block of RAM just to boot an operating system. A idle Linux system container under Incus can consume as little as 15–30 MB of RAM, compared to the 1–2 GB typically required by a fully virtualized Proxmox KVM instance. This allows organizations to increase container density on existing hardware by up to 3 to 5 times.

2. Image-Based Deployment and Blazing Fast Boot Times

Proxmox relies heavily on traditional ISO installations or template extractions. Incus utilizes a highly optimized image distribution system. Launching a new Debian, Ubuntu, or Rocky Linux system container takes less than a second, and the container achieves full initialization almost instantly. This agility is crucial for continuous integration (CI/CD) pipelines and auto-scaling infrastructures.

3. Pure API-First Design and Modern CLI

Proxmox features a robust web GUI, but its command-line interface and API can sometimes feel fragmented. Incus was built from the ground up with an API-first philosophy. Every action performed via the intuitive Incus command-line interface (CLI) is translated into an internal REST API call. This makes Incus exceptionally easy to integrate with modern Infrastructure as Code (IaC) tools like Terraform, OpenTofu, and Ansible.

4. Simplified Multi-Node Clustering

Setting up a Proxmox cluster requires strict quorum rules, often requiring a minimum of three nodes (or a QDevice) to prevent split-brain scenarios. Incus handles clustering natively via an embedded dqlite (distributed SQLite) database. Adding nodes to an Incus cluster is a single-command process, and the cluster gracefully handles distributed networking and storage without complex external dependencies.

Incus vs. Proxmox: A Feature Comparison

To help guide your engineering decisions, let us compare the core capabilities of both platforms side-by-side:

• Virtualization Focus: Proxmox excels at traditional KVM (Heavy VMs), whereas Incus prioritizes LXC/LXD System Containers while still supporting lightweight QEMU VMs.
• Storage Subsystems: Proxmox integrates deeply with ZFS and Ceph. Incus natively supports advanced storage backends including ZFS, Btrfs, LVM, and Ceph (RBD), allowing for instantaneous snapshots and cross-node migrations.
• Networking: Proxmox uses standard Linux bridging and SDN controllers. Incus features a highly sophisticated built-in networking stack supporting OVN (Open Virtual Network), bridge, macvlan, and SR-IOV, configurable via standard YAML declarations.
• Management Interface: Proxmox comes with a built-in, mature web dashboard. Incus focuses heavily on an elite CLI and REST API, though excellent open-source web UIs (such as the Incus-UI dashboard) are available and rapidly evolving.

Step-by-Step Overview: Migrating Workloads to Incus

Transitioning from a Proxmox environment to an Incus deployment involves evaluating your existing workloads. If your Proxmox VMs are running Linux, they are prime candidates for conversion into ultra-lightweight system containers under Incus.

1. Assess the Workload: Identify Linux-based VMs in Proxmox that do not require custom, non-Linux kernels (such as Windows, which must remain as full VMs).
2. Export the Root Filesystem: Stop the Proxmox container or VM and export its root directory or disk image.
3. Import into Incus: Use the incus import or incus-migrate tool to ingest the root filesystem directly into an Incus storage pool.
4. Apply Profiles: Assign network and security profiles (such as nesting permissions or GPU passthrough) to the newly created Incus container.
5. Launch: Execute incus start [container_name] to bring the service online instantly.

Conclusion: Is Incus Right for Your Infrastructure?

Replacing Proxmox with Incus is not about abandoning virtualization; it is about optimizing it for the modern era. If your organization relies heavily on Linux-based environments, microservices, development staging grounds, or high-density hosting, Incus offers an unmatched combination of bare-metal performance, operational simplicity, and minimal resource footprints.

By leveraging kernel-level security and sharing resources dynamically, Incus proves that you do not need the heavy overhead of a traditional hypervisor to maintain isolation, security, and control. As the enterprise landscape continues to demand cost reduction and hardware optimization, Incus stands out as the premier lean alternative to traditional virtualization platforms.