Just add the contents of your user's public key into $HOME/.ssh/authorized_keys.
To generate the key, type ssh-keygen. There's no reason to rely on DSA anymore, as the RSA patent has expired (I believe). Therefore you can use RSA keys which are much stronger.

Now that I've given you this advice, I should also advise you that by storing the keys on your NFS share, you are making yourself vulnerable... these private keys can be read in plain-text on the wire, and someone can steal them. Therefore, it's better if .ssh is a soft-link to a local filesystem and that the keys are replicated on each host.