Question

Your team maintains a network automation solution where Nautobot serves as the single source of truth (SoT). During a review, you discover that an engineer manually changed a VLAN description directly on a distribution switch via CLI, bypassing the automation pipeline. The next scheduled automation run overwrites this manual change back to the value stored in Nautobot. A colleague argues that Nautobot should instead be updated to reflect whatever is currently on the device. According to source-of-truth design principles for network automation, which action correctly preserves the integrity of the SoT model?

Accepted Answer

The pipeline is behaving correctly; the SoT defines intended state, so device drift should be reconciled by re-applying Nautobot's data, and any legitimate change must be entered into Nautobot first.

Answer

Configure the pipeline to automatically write the device's running configuration back into Nautobot on every run so the SoT always mirrors the live network.

Answer

Disable the automation pipeline for that switch and manage its VLANs exclusively through CLI to avoid future conflicts.

Answer

Store the VLAN description in both Nautobot and a separate YAML file, treating the most recently modified copy as authoritative during each run.