XCP ng
XCP-ng Overview
XCP-ng is an open-source virtualization platform built on the Xen hypervisor, offering a turnkey solution for managing virtual machines (VMs) across bare-metal servers. Originating as a community-driven fork of Citrix XenServer, XCP-ng removes proprietary limitations while retaining enterprise-grade features like live migration, high availability (HA), and multi-tenancy. Licensed under the GNU General Public License (GPL), it provides a cost-effective alternative to commercial hypervisors like VMware ESXi, emphasizing flexibility and scalability for private clouds and data centers.
Core Architecture and Components
XCP-ng combines the Xen Project hypervisor with a CentOS-based Dom0 (control domain) to manage hardware resources and VM operations. Key components include XAPI, the management API for orchestrating VM lifecycles, and Xen Orchestra, a web-based interface for monitoring, backups, and resource allocation. The platform’s RPM-based packaging integrates components like the patched Linux kernel, Xen tools, and open-source drivers, replacing proprietary elements of XenServer with community-driven alternatives. Storage and networking layers leverage blktap and tapdisk for efficient disk I/O, while XenBus facilitates communication between virtual devices via a split-driver model.
Hypervisor and Virtualization Capabilities
The Xen hypervisor underpins XCP-ng’s Type 1 architecture, supporting both Hardware Virtual Machines (HVM) and paravirtualized (PV) guests. HVM mode leverages Intel VT-x/AMD-V for unmodified guest OSes like Windows, while PV optimizes I/O performance for Linux guests using blkfront drivers. Nested virtualization and PCI passthrough enable GPU acceleration and specialized hardware access. Live migration transfers running VMs between hosts without downtime, while snapshotting preserves VM states for rapid rollbacks.
High Availability and Fault Tolerance
XCP-ng’s HA clustering automatically restarts VMs on healthy hosts during hardware failures, using shared storage (NFS, iSCSI) or distributed systems like Ceph. The Raft-based consensus protocol in Xen Orchestra ensures management plane resilience, while Xen Orchestra’s HA Manager monitors host health and enforces VM redundancy policies. Storage-agnostic HA mechanisms recover VMs even if local disks fail, prioritizing business continuity for critical workloads.
Storage and Networking
XCP-ng supports local disks, Fibre Channel, and software-defined storage (Ceph, StorPool) through tapdisk, which manages VHD files with libaio for asynchronous I/O. Distributed storage integration enables hyper-converged deployments, combining compute and storage roles on the same nodes. Networking features include VLAN tagging, Open vSwitch integration, and virtual router appliances for DHCP/NAT services, with bandwidth throttling and traffic shaping for QoS enforcement.
Management Tools and Ecosystem
Xen Orchestra serves as the primary management interface, offering VM provisioning, performance monitoring, and backup scheduling. The RESTful XAPI and Xen Orchestra API enable automation via Terraform, Ansible, and custom scripts. Multi-tenancy is enforced through role-based access control (RBAC), resource quotas, and isolated virtual data centers (VDCs). Third-party integrations include backup solutions like Veeam and monitoring tools like Zabbix.
Security and Compliance
XCP-ng inherits Xen’s security architecture, which isolates VMs via hardware-enforced memory protection. Features include UEFI SecureBoot, virtual Trusted Platform Module (vTPM) emulation, and encrypted VM disks. Role-based access control (RBAC) and audit logging ensure compliance with enterprise security standards, while SELinux integration hardens the Dom0 environment against privilege escalation attacks.
Use Cases and Enterprise Adoption
Organizations deploy XCP-ng for private cloud hosting, leveraging its compatibility with legacy XenServer environments and cost-efficient scaling. Service providers utilize multi-tenancy and self-service portals to offer VM hosting, while edge computing scenarios benefit from lightweight cluster deployments. The platform’s integration with Ceph and StorPool enables high-density workloads like databases and AI training, with live migration minimizing downtime during hardware maintenance.
Tool Link: https://xcp-ng.org/
