300-435: Automating and Programming Cisco Enterprise Solutions

Cisco IOS XE ZTP works by having the device request a Python bootstrap script (typically via DHCP options) and then execute that script to apply the device configuration. This script runs inside the IOS XE Guest Shell, a Linux container environment built into IOS XE that hosts the Python interpreter and associated libraries needed for on-box automation. Cisco's ZTP documentation specifies that the Guest Shell must be enabled on the device for the ZTP provisioning script to run and complete the automated configuration process.