Can use a private IP address as the puppet certname? Im very new to puppet but know in /etc/puppetlabs/puppet/puppet.conf I can set cert name to a url form following linux accadamy vidios but can you also set it to a private ip address.
Im trying to set up a puppet server and agent on my personal aws account replicateing what i did on my linux accadamy lab servers on ec2s except im trying to get it working with amozon ec2s rather than ubuntu 18.04.

I don't have a url set up for my ec2s as that costs extra can I use the ec2s private ip addresses rather than a url?
You can indeed use IP address in the "certname" directive of puppet.conf file.

In addition, you can create a private hosted zone in AWS Route53 that is called for example lab.local and then create an A record for your puppet server such as for example puppetmaster.lab.local and then use this address in the certname directive.

Opening a hosted zone in Route 53 doesn't cost much... around 0.50$ per month for your first 25 zones.

The full Route53 pricing can be found here.