A virtualized gateway for applications in a zero trust network access environment is managed from a cloud-based threat management facility for an enterprise network. In order to facilitate creation of a new, centrally managed gateway, a one-time passcode for registration of the gateway to the threat management facility is encoded onto a virtual disk and distributed to a host platform along with a base gateway image for the gateway. This advantageously permits the new gateway to boot and securely register with the threat management facility without further administrative intervention.