title: what can I install on the host CoreOS that will survive an update?
body: <p>In it's alpha state, CoreOS, will periodically update itself. If I'm installing apps and tools on the CoreOS host OS ... updating the /etc/ folder and so on. What can I expect after the next upgrade?</p>
  
  <p>It might be better to ask what is the idiomatic way to install apps and tools on the CoreOS host OS so that they survive an update?</p>
  
  <p>Another example: There are some tools I might like to install on the host like 'gear' or 'docker-yen'.  Both are available in source form and so I'd need to compile them. I suppose a Dockerfile would be the ideal way to go in order to compile and export. But is it?</p>