OVN-based Virtual Network Automation

A lightweight project to automate virtual networking for small-scale private cloud environments using Open vSwitch (OVS) and OVN.
This project focuses on simplicity and efficiency, without relying on heavyweight SDN controllers.

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✨ Features

• Automated Port Management

  • Dynamically add OVS ports during VM creation.

• Isolated Subnet Allocation

  • Assign VXLAN tunnels for VMs requiring separate subnets.

• Gateway Integration

  • Use the Control server’s OVS L3 switch as a gateway for internal ↔ external connectivity.

• Lightweight Automation

  • Replace traditional controllers (e.g., OpenDaylight) with gRPC APIs + Python bindings for OVS.

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🏗️ Architecture Overview

+-------------------+  
| Client (VM API)   |  
+-------------------+  
|                   |  
| api               |  
v                   |  
+-------------------+ +--------------------+  
| Control Server |------| External Network |  
| (Automation) | GW | (Internet / LAN)     |  
| | +--------------------------------------+  
| - api gateway                            |  
| - OVS/OVN controller, northd Mgmt        |  
+---------+---------------------------------+  
|    control node    |  
| OVS Port / VXLAN   |  
v                    |  
+--------------------+  
| Compute Nodes      |  
| (VM Instances)     |  
+-------------------+

• Client: Sends VM creation/deletion requests.
• Control Server:
  • Runs OVS/OVN.
  • Manages ports, VXLAN tunnels, and L3 gateway rules.
  • Provides gRPC APIs for automation.
• Compute Nodes: Host VMs connected to OVS bridges.

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🔧 Core Components

1. Control Server

• OVS/OVN Integration
  • Handles port creation (ovs-vsctl add-port).
  • Allocates VXLAN tunnels for network isolation.
  • Exposes VM lifecycle hooks (create, delete).
  • Communicates with compute nodes for sync.

2. Network Layer

• Geneve for tenant-level segmentation.

3. VM Management

• VM network interfaces dynamically attach to OVS bridges.
• Each VM can be assigned to:
  • Default subnet (shared)
  • Dedicated isolated ip subnet

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⚠️ Notes

• Tested in debian based environment.
• May require modification of filesystem paths and OVS configuration depending on distribution.

🚀 A step toward lightweight cloud networking automation for developers and small private clouds.