There are two methods for recovering node agents and sever instances.
Keep a backup zip file. There are no explicit commands to back up the node agent and server instances. Simply create a zip file with the contents of the node agents directory. After failure, unzip the saved backup on a new machine with same host name and IP address. Use the same install directory location, OS, and so on. A file-based install, package-based install, or restored backup image must be present on the machine.
Manual recovery. You must use a new host with the same IP address.
Install the Enterprise Server with node agent on the machine.
Recreate the node agents. You do not need to create any server instances.
Synchronization will copy and update the configuration and data from the DAS.