Case Study: Swisscom achieves 99% time savings in Hiera data generation with Puppet (Hieragen/Stackgear)

Hiera data generation at Swisscom

Swisscom, a Swiss telecommunications and IT services provider, needed to build custom cloud stacks for enterprise customers but found Hiera data creation for Puppet modules slow, error-prone and labor-intensive. Engineers typically spent about two working days preparing Hiera configurations for a new cloud stack, which limited scalability and introduced risk of manual mistakes.

Swisscom developed an automated generator—initially the Ruby-based Hieragen (ERB templates producing YAML) and later the production-grade Stackgear—packaged as RPMs and integrated with GitLab. The tool collects source data, renders module-specific Hiera files and uploads them for use by Puppet; the process now takes about one minute to generate (roughly 10 minutes including source prep), cutting work from two days to ~11 minutes (≈99% time saved), enabling CI/CD, fewer errors and far more scalable deployments.

Swisscom

Raffaela Wüst

Application Engineer