Virtual networking is becoming an increasingly popular way to efficiently utilize network resources and isolate network traffic. One technology enabling the creation of extensive virtual networks over existing physical infrastructures is VXLAN (Virtual Extensible LAN). This article provides a detailed guide on creating and managing virtual networks using VXLAN on the CentOS 7 operating system.

What is VXLAN?

VXLAN is a network technology that extends LAN over large distances through underlying network infrastructure using tunneling. VXLAN allows for the creation of logical networks for virtual machines across different networks without requiring physical changes in the infrastructure. This simplifies network management and enhances security and isolation among individual virtual networks.

Prerequisites

Before starting, you need to have:

• CentOS 7 installed on all nodes that will be part of the VXLAN.
• Network interfaces configured and operational on all nodes.
• User rights to execute commands as root or using sudo.

Installation and Configuration

1. System Update The first step is to ensure your system is up to date. This can be done using the command:

   sudo yum update -y
   

2. Network Tools Installation Working with VXLAN requires network management tools. These can be installed using:

   sudo yum install bridge-utils net-tools -y
   ​

3. Creating a VXLAN Network Interface To create a VXLAN interface, we use the ip tool. Example of creating a VXLAN interface with identifier 42:

   sudo ip link add vxlan42 type vxlan id 42 dstport 4789
   sudo ip link set up dev vxlan42
   

4. Assigning an IP Address to the VXLAN Interface Each VXLAN interface needs an IP address to communicate with other nodes in the VXLAN network. Example of assigning an IP address:

   sudo ip addr add 192.168.1.1/24 dev vxlan42
   ​

5. Configuring Static VXLAN Tunneling To connect two nodes via VXLAN, it's necessary to configure static tunneling. This can be done by explicitly specifying the target IP addresses of the nodes at both ends. Example:

   sudo ip link set vxlan42 vxlan remote 192.168.1.2
   ​

6. Testing Connectivity After configuration, it's important to verify that the VXLAN network is functioning correctly. This can be done using a ping test to the IP address at the other end of the tunnel.

   ping 192.168.1.2
   ​

Management and Maintenance

For managing VXLAN networks, it's important to regularly monitor network traffic and perform software updates on all nodes. Additionally, it's recommended to perform configuration backups and test backup recovery to ensure quick restoration in case of failure.

VXLAN offers a flexible and scalable way to manage virtual networks. Following this guide, you should be able to establish and manage VXLAN networks on your CentOS 7 system.