No, Cisco ACI Leaf or Spine switches cannot be configured to act as NTP servers to provide NTP information to external devices. The ACI fabric, including Leaf and Spine switches, can be configured to use NTP servers to synchronize their own clocks, but they do not have the capability to serve as NTP servers for other devices.
If you need to provide NTP services to other devices in your network, you will need to use a dedicated NTP server or configure another network device that supports NTP server functionality, such as a router, a dedicated NTP appliance, or a server running NTP server software.
