Kadeploy is a scalable, efficient, and reliable bare-metal provisioning solution for HPC clusters. In this talk, I will first present the design choices that enable system administrators to install a 300-nodes cluster in a couple of minutes. Then, I will present how Kadeploy is used in the context of the Grid'5000 testbed. Grid'5000 is a large-scale testbed for research on HPC, Cloud, Grid and P2P computing, where Kadeploy provides users with the ability to deploy their own software stacks, making it the ideal testbed to design, test and evaluate IaaS Cloud stacks.