One of the toughest hurdles to overcome when building your own virtual networking lab is the slog of downloading VM images for your favorite network devices and building Vagrant boxes[^VB] in case you want to use them with Vagrant or netlab.

You can find box-building recipes on the Internet – codingpackets.com has at least a dozen – but they tend to be a bit convoluted and a smidge hard to follow the first time you’re trying to build the boxes (trust me, I’ve been there).

I finally had enough and built a simple scaffold for Vagrant box-building for the vagrant-libvirt provider. You still have to deal with vendors stonewalling the image-downloading process, but then the netlab libvirt package command takes the mundane parts out of the process:

• It copies the VM image into a temporary directory (recent Linux distributions don’t give KVM/libvirt access to your home directory)
• When needed, it unpacks/converts the VM image (we support QCOW, OVA, ZIP, and ISO formats)
• It starts a VM and kills it after you’re done with initial configuration
• It packs the modified VM disk image as a Vagrant box and adds the desired metadata.

While there are people brave enough to go for a fully automated process (example), I don’t want to be a perpetual maintainer of ever-changing quirks – you’ll still have to do a few bits on your own with the help of as-simple-as-they-can-get instructions.

The current netlab version can build around two dozen Vagrant boxes (the up-to-date list is here). If you feel like contributing another box-building recipe, please submit a PR.

Other options:

• You can use the vrnetlab fork to build VM-in-Docker containers for a number of platforms and use them with netlab.
• GNS3 is always an option for GUI enthusiasts.

Release History

2026-09-13

Cleaned up obsolete information, added more links/details

2022-02-15

netsim-tools release 1.1.3 added build recipes for Cisco CSR and Juniper vSRX.