Spine-Leaf (Clos) with Cumulus VX (vagrant up) – Part 1:underlay


This blog post will demonstrate how to quickly setup a two-tier L3 spine-leaf (Clos) lab using Cumulus VX and Vagrant.  The L3 spine-leaf underlay will use BGP (*Quagga) as the routing protocol. This post is primarily focused on building the underlay, future posts will include routing on the host and deploying an overlay (VXLAN EVPN), stay tuned…

*Note: Cumulus is replacing Quagga with FRRouting


Software Used To Build This Out…

  • Vagrant (I used version 1.9.5)
  • VirtualBox (I used version 5.1.22)
  • Cumulus VX image* (I used version 3.3.0) *Note: this image (Vagrant box) will automatically be pulled down from Atlas by HashiCorp based on the configuration within the Vagrantfile (shown below)

***I installed all of the above on a Windows 10 machine***


Now that we have the materials, lets build…

To start this build we will need the Vagrantfile, this file will do all the magic of deploying and configuring four Cumulus VX leaf switches and two Cumulus VX spine switches all peering via eBGP. This Vagrantfile can be copied/cloned from my GitHub account found here: https://github.com/michaelc0n/cumulusvx_bgp_lab_1


Vagrant Up!

After the Vagrantfile has been copied to your local machine, navigate to the directory containing the Vagrantfile and issue a “vagrant up”.  After a few minutes you should have the topology shown below with SSH access into each switch…



  • Username/Password for switch SSH access: ‘vagrant
  • Once connected enter “sudo vtysh“, this will drop you into Quagga where you can issue BGP commands like “show ip bgp summary
  • See topology diagram below for IP address information

Sample output from spine1 :

spine1# show ip bgp summary
BGP router identifier, local AS number 65500 vrf-id 0
BGP table version 13
RIB entries 25, using 3400 bytes of memory
Peers 4, using 84 KiB of memory
Peer groups 1, using 72 bytes of memory

Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
leaf1(swp1) 4 65101 127 124 0 0 0 00:05:49 3
leaf2(swp2) 4 65102 127 124 0 0 0 00:05:49 3
leaf3(swp3) 4 65103 127 124 0 0 0 00:05:49 3
leaf4(swp4) 4 65104 127 124 0 0 0 00:05:49 3

Total number of neighbors 4

Clos Topology

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