Puppet – Server Error: hiera configuration version 3 cannot be used in an environment

Today I found my homelab puppet setup failing. I mostly run the latest released puppet code on my setup and this time it bit me in the ass :

Error: Could not retrieve catalog from remote server: Error 500 on SERVER: Server Error: hiera configuration version 3 cannot be used in an environment on node buzz.maljaars-it.nl
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run

When looking it at the issue, I found that my setup had automatically been upgraded to puppet code version 4.9. This version supports a newer hiera config file version without maintaining backward compatibility apparently.

Looking for documentation on the new format, it seems to be missingat this time. Searching the history on the puppet community slack seems to confirm this.

For now I downgraded the puppet-agent package on the puppetserver machine and pinned it to the previous release. After restarting the puppetserver service everything was fine for now.

More info on this issue and other new features of puppet 4.9 : https://docs.puppet.com/puppet/4.9/release_notes.html