Modifying LTM hostname

Hello,

This article will help you: sol15700: Changing the BIG-IP hostname does not update the device name when the device is a member of a DSC device group

When you change the hostname of a standalone BIG-IP system, both the hostname and the device name are updated. However, if the system is a member of a device group, the device name is not automatically updated, because it would affect the device trust established between device group members.

You have to follow this Recommendations:

While it does not affect the BIG-IP system's functionality to have the hostname and device name not match, you may want to see the new hostname in all configuration instances.

When changing the hostname for a member (or members) of a device group, if you want the device name to match the new hostname, you must perform all of the following procedures:

•Reset the device trust across all devices

•Change the device name

•Re-add the devices to the device group

•Perform ConfigSync (optional)

https://support.f5.com/kb/en-us/solutions/public/15000/700/sol15700.html

Regards,