Lab Topology Reference

The lab topology is described in a YAML file using a dictionary format. You could use hierarchical attribute names as dictionary keys to make the topology file more readable.

The three major components that should be present in every topology file are:

Other topology elements include:

  • provider – virtualization provider (default: libvirt)

  • groups – optional groups of nodes

  • module – default list of modules used by this network topology. You can use device-level module attribute to override this setting for individual nodes.

  • addressingIPv4 and IPv6 pools used to address management, loopback, LAN, P2P and stub interfaces

  • name – topology name (used in bridge names)

  • plugin – list of plugins used by this topology.

  • message – a help message to display after successful netlab initial or netlab up commands. You can use that message to tell the end-user how to use the lab (example: VLAN integration test cases).


  • All elements apart from nodes are optional – missing links element indicates a topology without inter-node links (just the management interfaces)

  • Default values of defaults and addressing elements are taken from default settings.

  • List of modules is used to specify additional initial configuration elements (example: OSPF routing)

  • Default topology name is the directory name.

You’ll find sample topology files in the tutorials.