Running netlab on a Linux Server

This page describes generic installation steps you have to follow to create a virtual lab environment on any Linux server. If you plan to run your labs on a Ubuntu server, follow these instructions.

Prerequisite Software Installation

netlab is a Python package that uses KVM to run virtual machines and Docker to run containers. Virtual machines in KVM environment and the associated Linux bridges are created with Vagrant using libvirt API. Ansible is used to configure the network devices.

netlab on Linux

To build a Linux environment needed to run network devices as virtual machines or containers:

  • Install Python 3.8 or later

  • Install KVM and libvirt

  • Install Vagrant 2.2.14 or later

  • Install vagrant-libvirt plugin with vagrant plugin install libvirt --plugin-version=0.11.2

  • Install Ansible 2.9.1 or later and any Ansible networking dependencies (example: paramiko)

  • Optional: install Docker and containerlab

netlab Installation

Install Python package with sudo python3 -m pip install networklab or your preferred Python package installation procedure.

Tip

Installing Python packages as root is not the recommended best practice. Please use your regular Python package installation process if you’re not setting up a throwaway VM/server.

Creating vagrant-libvirt Virtual Network

vagrant-libvirt plugin connects management interfaces of managed VMs to vagrant-libvirt virtual network. Vagrant can figure out the device IP address based on dynamic DHCP mappings; netlab can’t. To make the Ansible inventory created by netlab create work, your virtual network MUST include static DHCP bindings that map management MAC addresses defined in netlab data model into expected IP addresses.

netlab up command automatically creates vagrant-libvirt virtual network with correct static DHCP bindings before calling vagrant up, so you SHOULD use netlab up instead of executing vagrant commands. Recent versions of vagrant-libvirt plugin remove the vagrant-libvirt virtual network on vagrant destroy, so it makes no sense to create that network manually.

Testing the Installation

The easiest way to test your installation is to use netlab test command. If you prefer to do step-by-step tests, you might find this recipe useful:

  • Create an empty directory and topology.yml file with the following contents within that directory:

---
defaults:
  device: cumulus

module: [ ospf ]

nodes: [ s1, s2, s3 ]
links: [ s1-s2, s2-s3, s1-s2-s3 ]
  • Start the lab with netlab up

  • Connect to the Cumulus VX devices with vagrant ssh or netlab connect

  • Destroy the lab with netlab down