Containerlab vs GNS3

Containerlab is a command-line tool for orchestrating container-based networking labs. Users describe nodes, links and lab settings in topology files, then use lifecycle commands to deploy, destroy, save, inspect or graph a lab. Supported nodes include containerized and virtual-machine network operating systems from Nokia, Cisco, Juniper, Arista and other vendors and projects. The project lists platforms such as Nokia SR Linux and SR OS, Cisco XRd and Nexus 9000v, Juniper cRPD and vMX, Arista, SONiC, Cumulus VX, VyOS, FRR, VPP, FreeBSD, OpenBSD, OpenWRT, Linux containers and generic VMs. It can launch VM routers through vrnetlab or boxen, and Clabernetes can run Containerlab-style topologies on Kubernetes. Optional interfaces include a VS Code extension, desktop app and web app; desktop and web connect to a reachable clab-api-server on a Linux host. Its single binary and topology definitions can start labs in CI systems such as GitLab CI and GitHub Actions. Containerlab is free and open source. Documented prerequisites include a Linux server or VM, Docker and sudo privileges for some operations.

GNS3 is free, open-source software for emulating, configuring, testing, and troubleshooting virtual and real networks. Its graphical client works with a virtual machine, and servers can run locally or remotely. Users can combine emulated devices running actual images with simulated devices, including a built-in layer 2 switch. It supports appliances from vendors such as Cisco, Brocade, Cumulus Linux, and HPE, as well as Docker, QEMU-based appliances, VMware, VirtualBox, Hyper-V, and connections to real networks. The GNS3 Marketplace offers preconfigured appliance templates with recommended settings. It runs on Windows, macOS, and Linux; documentation recommends the GNS3 VM for most Windows and macOS setups and complex topologies. Users must supply their own Cisco IOS images. There are no monthly or yearly license fees, and device capacity depends in practice on the host computer’s CPU and memory. GNS3 is used for networking education, certification practice, proofs of concept, demonstrations, and interoperability testing. A server has no authentication enabled by default and should be restricted at the network level.