Vagrantfile used to provision the Cumulus Demo Reference Topology
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Cumulus Linux Demo Framework

Reference Topology

Welcome to the Cumulus Linux Demo Framework, which provides virtual demos of features and configurations with Cumulus Linux. Follow the Prerequisites and Getting Started instructions below to get started.

Table of Conents

Prerequisites and Getting Started

Instructions for:

Available Demos

Once you've followed the above prerequisite/getting-started instructions for your system, you are able to run any of the demos below.

Demos are built upon the Reference Topology as a starting point and then layer specific device configuration on top.

  • Cldemo-config-routing -- This Github repository contains the configuration files necessary for setting up Layer 3 routing on a CLOS topology using Cumulus Linux and Quagga.
  • Cldemo-config-mlag -- This demo shows a topology using MLAG to dual-connect hosts at Layer 2 to two top of rack leafs and uses BGP unnumbered/L3 for everything above the leaf layer.
  • Cldemo-roh-ansible -- This demo shows a topology using 'Routing on the Host' to add host reachability directly into a BGP routed fabric.
  • Cldemo-roh-docker -- This demo shows how to redistribute docker bridges into a Routing on the Host container to advertise host container subnets into a BGP routed fabric.
  • Cldemo-roh-dad -- This demo shows how to dynamically advertise host-routes for container IP addresses into a Routing on the Host Container to advertise containers into a BGP routed fabric.
  • Cldemo-automation-puppet -- This demo demonstrates how to write a manifest using Puppet to configure switches running Cumulus Linux and servers running Ubuntu.
  • Cldemo-automation-ansible -- This demo demonstrates how to write a playbook using Ansible to configure switches running Cumulus Linux and servers running Ubuntu.
  • Cldemo-automation-chef -- This demo demonstrates how to write a set of cookbooks using Chef to configure switches running Cumulus Linux and servers running Ubuntu.
  • Cldemo-puppet-enterprise -- This demo demonstrates how to setup Puppet Enterprise to control Cumulus Linux switches with Puppet manifests.
  • Cldemo-ansible-tower -- This demo demonstrates how to setup Ansible Tower to control Cumulus Linux switches with Ansible playbooks.
  • Cldemo-openstack -- Installs Openstack Mitaka on servers networked via Cumulus Linux
  • Cldemo-onie-ztp-ptm -- This demo demonstrates how to configure an out of band management network to automatically install and configure Cumulus Linux using Zero Touch Provisioning, and validate the cabling of the switches using Prescriptive Topology Manager.
  • Cldemo-rdnbr-ansible -- This demo shows a topology using 'redistribute-neighbor' to add host reachability directly into a BGP routed fabric.
  • Cldemo-pim -- This demo implements Cumulus Linux PIM EA version. The demo includes simple python applications to simulate multicast senders and receivers.
  • Cldemo-evpn -- This demo implements EVPN on Cumulus Linux. This demo is standalone and does not require cldemo-vagrant.
  • Cldemo-dynamic-ansible-inventory -- A demonstration of using Ansible with external data sources, specifically Redis or MySQL databases.
  • Cldemo-docker-macvlan -- A demonstration of advertising docker containers using the macvlan networking option.
  • NetQDemo-1.0 -- Demos using NetQ. NOTE: The NetQ VM is available for Cumulus Customers
  • cldemo-evpn-symmetric -- Provides a setup to show a VXLAN Routing with EVPN environment using the symmetric IRB model.

Frequently Asked Questions


CLDEMO-VAGRANT is the name of this repository which provides a consistent physical topology of VMs which are cabled together in a configuration we refer to as the Reference Topology. This topology provides a consistent simulation topology upon which lots of different configurations can be overlaid. The individual demos provide interface and routing protocol configurations which are applied to this simulation topology.

What is the Reference Topology?

The Cumulus Linux Demo Framework is built upon a Vagrantfile which builds the Reference Topology. Using this topology, it is possible to demonstrate any feature in Cumulus Linux. It may not be necessary to use all links or all devices but they're present if needed by a particular demo.

This framework of demos is built on a two-tier spine-leaf Clos network with a dedicated out-of-band management network. The Reference Topology built in this repository is used for all Cumulus Networks documentation, demos, and course materials, so many demos will require you to build a topology using the code available in this repository.

What is Cumulus VX?

This repository makes use of Cumulus VX which is a virtual machine produced by Cumulus Networks to simulate the user experience of configuring a switch using the Cumulus Linux network operating system.

What is Vagrant?

Vagrant is an open source tool for quickly deploying large topologies of virtual machines. Vagrant and Cumulus VX can be used together to build virtual simulations of production networks to validate configurations, develop automation code, and simulate failure scenarios.

Vagrant uses Vagrantfiles to represent the topology.

What is a Vagrantfile?

Vagrant topologies are described in a text file called a "Vagrantfile," which is also the filename. A Vagrantfile is a Ruby program that tells Vagrant which devices to create and how to configure their networks. vagrant up will execute the Vagrantfile and create the reference topology using Virtualbox.

What is Libvirt/KVM?

Libvirt/KVM is a high-performance hypervisor that is used on Linux systems ONLY. Vagrantfiles for the Libvirt/KVM hypervisor are also included in this repository. To use them you need to be using a Linux system and follow the Linux setup instructions.

Libvirt/KVM offers several notable advantages over Virtualbox:

  • There is no interface limit (virtualbox limits VMs to 36 interfaces)
  • VMs can be started in Parallel which greatly reduces simulation startup time

As a result this tends to be the most common hypervisor for larger simulations.

Which Software Versions Should I Use?

Software versions are always changing. At the time of this writing the following versions are known to work well:

  • Vagrant v2.0.2
  • Virtualbox v5.1.22
  • Libvirt v1.3.1

What Is The Out Of Band Server Doing?

The following tasks are completed to make using the topology more convenient.

  • DHCP, DNS, and Apache are installed and configured on the oob-mgmt-server
  • Static MAC address entries are added to DHCP on the oob-mgmt-server for all devices
  • A bridge is created on the oob-mgmt-switch to connect all devices eth0 interfaces together
  • A private key for the Cumulus user is installed on the oob-mgmt-server
  • Public keys for the cumulus user are installed on all of the devices, allowing passwordless ssh
  • A NOPASSWD stanza is added for the cumulus user in the sudoers file of all devices

After the topology comes up, we use vagrant ssh to log in to the management device and switch to the cumulus user. The cumulus user is able to access other devices (leaf01, spine02) in the network using its SSH key, and has passwordless sudo enabled on all devices to make it easy to run administrative commands. Further, most automation tools (Ansible, Puppet, Chef) are run from this management server. Most demos assume that you are logged into the out of band management server as the cumulus user.

Note that due to the way we simulate the out of band network, it is not possible to use vagrant ssh to access in-band devices like leaf01 and leaf02. These devices must be accessed via the out-of-band management server.

How are IP addresses Allocated?

The Reference Topology only specifies the IP addresses used in the Out-of-Band network for maximum flexibility when creating new demos. To see the IP address allocation for the Out-of-Band Network check the IPAM diagram

Tips on Managing the VMs in the Topology

The topology built using this Vagrantfile does not support vagrant halt or vagrant resume for in-band devices. To resume working with the demos at a later point in time, use the hypervisor's halt and resume functionality.

In Virtualbox this can be done inside of the GUI by powering off (and later powering-on) the devices involved in the simulation or by running the following CLI commands:

* VBoxManage controlvm leaf01 poweroff
* VBoxManage startvm leaf01 --type headless

When using the libvirt/kvm hypervisor the following commands can be used:

* virsh destroy cldemo-vagrant_leaf01
* virsh start cldemo-vagrant_leaf01

Factory-reset a device

vagrant destroy -f leaf01
vagrant up leaf01

Destroy the entire topology

vagrant destroy -f

Can I Preserve My Configuration

In order to keep your configuration across Vagrant sessions, you should either save your configuration in a repository using an automation tool such as Ansible, Puppet, or Chef (preferred) or alternatively copy the configuration files off of the VMs before running the "vagrant destroy" command to remove and destroy the VMs involved in the simulation.

One helpful command for saving configuration from Cumulus devices is:

net show configuration files


net show configuration command

This command will not show configuration for third-party applications.

Running More Than One Simulation At Once

Using this demo environment, it is possible to run multiple simulations at once. The procedure varies slightly from hypervisor to hypervisor.


In the Vagrantfile built for Virtualbox there is a line which sets simid= [some integer] in order to create unique simulations a text editor can be used to modify the simid value to something unique which does not match other running simulations on the simulation node.


In the Vagrantfile built for Libvirt (Vagrantfile-kvm) virtual networks are built from link to link using UDP tunnels. In order to make sure that the VMs do not collide with each other. By default the demo uses ports 8000-10000 but these values can be swapped either by:

A). Running the Customize the Topology workflow below and providing a '-s' argument OR B). By modifying the Vagrantfile-kvm directly, swapping the prepending 1000's place for the port numbers to something different that do not overlap with any running applications or ports. In the example below we're swapping the ports used by the simulation from 8000-10000 --> 30000-32000. _port => '8 --> _port => '30 _port => '9 --> _port => '31

How Can I Customize the Topology?

This Vagrant topology is built using Topology Converter. To create your own arbitrary topology, we recommend using Topology Converter. This will create a new Vagrantfile which is specific to your environment.For more details on how to make customized topologies, read Topology Converter's documentation.

**Advanced Users ONLY: ** Editing the existing topology

This can be a bit tricky, to edit the existing topologies you can bring in the required portions of Topology Converter needed to get the job done. The process looks like what is featured below and is also found in the script used to rebuild and update this environment.

vagrant destroy -f
mkdir ./templates/
wget -O ./templates/Vagrantfile.j2
# edit as desired

Quick Start:

Before running this demo or any of the other demos in the list below, install VirtualBox and Vagrant.

NOTE: On Windows, if you have HyperV enabled, you will need to disable it as it will conflict with Virtualbox's ability to create 64-bit VMs.

Provision the Topology and Log-in

git clone
cd cldemo-vagrant
vagrant up oob-mgmt-server oob-mgmt-switch leaf01
vagrant ssh oob-mgmt-server
ssh leaf01

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