Can we switch to using ec2 metadata as a set of key/value pairs? Overloading a blob of metadata as we have been so far is a kludge that grew up organically. Originally the script completely assumed that the only thing the metadata could be was a gist url to a ssh key. That eventually evolved into maybe just a unique string, into maybe a non-gist url, into maybe a url to a script, etc... We need to cut it out and use a cloud-init style structured text format.

Fortunately Google provides key-value storage natively in its API but for EC2 we need to pick a text format.