While working on T389554: Add some integration executors to spread the load and manually running through the checklist at https://wikitech.wikimedia.org/wiki/Nova_Resource:Integration/Setup some of us started wondering about using the relatively new https://wikitech.wikimedia.org/wiki/Help:Using_OpenTofu_on_Cloud_VPS features to manage our pool of Jenkins agents.
https://gitlab.wikimedia.org/cloudvps-repos/deployment-prep/tofu-provisioning could be inspiration for getting a basic OpenTofu setup going. More about that project and the steps it took to get started can be found in T372498: Figure out how to provision a Kubernetes cluster using Magnum and OpenTofu.
Research is needed to determine if there is an opentofu/terraform provider that can be used to configure Jenkins to work with a new node or if we would need to invent something new for that work. Even if we are not able to fully automate joining nodes to the Jenkins instance having the multi-step provisioning process reduced to changing some instance counts and flavors in a config file would be a large improvement over the current very manual process.