Capistrano question

When configuring the ssh_options[:keys] options. It says it should have
a value of path/to/ssh/id_rsa. Is that on my local machine or on the
host machine?

id_rsa is your private key and should stay on your local machine; keep
it secret; it will take the place of your password when logging in to
the server. If you're worried it may be accessed by other people then
encrypt it with a passphrase. is the public key and you can push that up to your server
and (usually) stick it in ~/.ssh/authorized_keys. (see ssh-copy-id)
ssh_options needs to know the private key so that it can authenticate
you with your server (once you've pushed up your public key).