If you're like me this morning and can not seem to GTFM, let me tell you that after starting up your CoreOS instance (on a bare metal setup), the configuration file gets copied to:
And for extra search engine indexing joy I paraphrase: The Cloud Config file (often named
cloud-config.yaml) is located at
/var/lib/coreos-install/user_data inside the instance.
Phew... this is perfectly clearly written in the fine manual.
Oh and if you choose to have fun with a few instances under QEMU the file is created/mounted at: