> so if any new host spin up not required to add manually on targets
That depends on how you are detecting the new hosts which are spun up.Ā Prometheus normally does this using "service discovery".Ā You are currently using the "file" service discovery mechanism, which reads your targets.yml file, but there are many other options which you can read about in the prometheus documentation.
> I want to know that can I manage this Targets.yml from puppetĀ
If you wish to continue using the file service discovery mechanism (i.e. use targets.yml and manage it through puppet), then it's up to you to work out how to detect a new hosts, update targets.yml, and push it out.