Two-Level Nested Virtualization Infrastructure with Proxmox VE & Ubuntu

#devops #cloud #linux #proxmox

📌 Overview & Architecture

Virtualization is at the core of modern cloud environments. In this project, I implemented and validated a Two-Level Nested Virtualization Infrastructure (Hypervisor-on-Hypervisor) to test multi-tier resource allocation, network bridging, and inter-VM connectivity.

🏗️ Environment Topology

Host Level (L0): Physical Workstation (VMware Workstation)
Level 1 (L1 Hypervisors):
- Proxmox VE (L1 Node)
- Ubuntu Server (L1) with Apache2 / Cockpit
Level 2 (L2 Virtual Machines):
- Proxmox VE (L2 Node) running inside L1 Proxmox
- Ubuntu Server (L2 Node) running inside L1 Proxmox

🛠️ Implementation Highlights

CPU Passthrough & Virtualization Flags:
Enabled nested virtualization extensions (VT-x/AMD-V) in VMware to allow L1 hypervisor to host secondary virtual machines (L2).
Network Bridging Configuration:
Configured Linux bridges (vmbr0) across L1 and L2 layers to provide direct network visibility and IP assignment across all instances.
Remote Node Management:
Enabled remote management via Proxmox Web Interface (Port 8006) and Linux Cockpit Admin Dashboard (Port 9090).

🌐 Network Matrix & Connectivity Verification

A structured ICMP Ping Matrix was conducted to verify that all nodes can communicate seamlessly across layers without packet loss or bridge isolation issues:

Source Node	Destination Node	Status
Host (L0)	L1 Proxmox / L1 Ubuntu	✅ Connected
Host (L0)	L2 Proxmox / L2 Ubuntu	✅ Connected
L1 Proxmox	L1 & L2 Guest Virtual Machines	✅ Connected
L2 Proxmox	L1 Hypervisors & L0 Host	✅ Connected

📊 Remote Management & Interface Validation

Remote access was verified from multiple devices on the network, including web management on mobile endpoints:

Proxmox VE (L1 Node): https://10.250.73.43:8006
Proxmox VE (L2 Node): https://10.250.73.249:8006
Ubuntu Cockpit Web Console: Ports 9090 across active Ubuntu instances (vm11ubuntu, vm12ubuntu, vm2ubuntu).

💡 Key Takeaways

Overhead Control: Nested virtualization introduces minor CPU/RAM overhead, requiring careful resource allocation per VM layer.
Bridging vs NAT: Using standard virtual bridging simplifies inter-VM communication in complex nested labs.
Infrastructure Testing: This setup serves as an effective, cost-free sandbox for testing hypervisor clusters, cloud migration, and IaC pipelines locally.

📸 Project Execution Screenshots & Verification Gallery

Below are the operational screenshots verifying system deployment, active services, and multi-device network connectivity across all L1 and L2 instances: