Johannes worked on the SUNET/puppet-sunet repository, focusing on improving the reliability of virtual networking deployments by addressing a critical bug in KVM NAT bridge interface configuration. He enhanced the Puppet module to support optional nat_bridge_interface settings and corrected the script path for sunet-kvm-modify-forwardmode, reducing the risk of misconfiguration when the interface is unset. His approach involved validating changes across multiple test environments to ensure compatibility with existing Puppet workflows. Leveraging his skills in Infrastructure as Code, system administration, and Puppet, Johannes demonstrated a deep understanding of Linux networking and virtualization infrastructure through this targeted engineering effort.