Working on large server deployments is a blast! And CoreOS makes it even more fun via its read-only focus. In our system we don't do automated updates since w

Working on large server deployments is a blast! And CoreOS makes it even more fun via its read-only focus. In our system we don't do automated updates since we don't need that functionality. In order to send out an update I download the image that I want to deploy, patch it with CPIO (with my custom initialization code) and then register it with DNSMasq (put it in a directory). At that point any machine that reboots will start up with the new image rather than the old one. I usually test one/two machines and then if they look good a script reboots the rest. If you wanted to do automated deployments, you could basically do the same thing provided you have a server to manage the process. The master server would simply poll CoreOS for new releases, and then do the same steps as above to roll out the image. Incremental updates are trivial as well since you are just rebooting the machines. One thing to consider is running CoreOS out of memory rather than installing it to disk. I find this is one of the best features of CoreOS since it makes it even harder to think of a machine as any more than a temporary computing resource. Hope that helps! Good luck!