Worth Reading: Lab as Code (Containerlab and Netlab)

Key Takeaways

• Netlab 26.04 adds bgp.advertise attribute for prefix advertising
• Dual‑stack bgp.originate now works via static discard routes
• Documentation clarifies bgp.as vs vrf.as and adds router_id attribute
• bgp.policy plugin bug fixed, restoring module node attribute functionality

Pulse Analysis

Containerlab and netlab have become the de‑facto platforms for "lab as code," allowing engineers to spin up complex network topologies with a single YAML file. The latest netlab 26.04 release builds on that foundation by adding the bgp.advertise attribute, which lets users declaratively specify which prefixes each device should announce. This aligns netlab with industry‑standard BGP configuration practices across Cisco IOS, Arista EOS, Junos, and other platforms, reducing the need for manual script tweaks and accelerating test cycles.

Beyond the new attribute, the update resolves a critical gap in dual‑stack environments. By leveraging static discard routes, netlab now supports bgp.originate for both IPv4 and IPv6, even within VRF contexts. This capability enables realistic simulation of route origination and policy enforcement, a common requirement for service provider labs. The fix also standardizes static routing support across a broader set of devices, ensuring consistent behavior regardless of vendor‑specific quirks.

The release also tightens documentation and bug fixes that improve overall usability. Clarifications around the bgp.as versus vrf.as distinction and the addition of a router_id field eliminate confusion for newcomers, while the corrected bgp.policy plugin restores proper handling of module node attributes. These refinements, driven by community contributions, underscore the collaborative nature of open‑source networking tools and their rapid evolution to meet enterprise lab automation needs.