For this, on local machine do:
ssh-keygen and agree with all defaults (if you have no reasons do otherwise)
cat ~/.ssh/id_rsa.pub and copy that key
On remote machine:
mkdir ~/.ssh && chmod 700 ~/.ssh
touch ~/.ssh/authorized_keys2 && chmod 600 ~/.ssh/authorized_keys2
Paste copied key into authorized_keys2
From now your remote machine “trusts” your local machine and allows logging it in without password. Handy.
Copied from http://stackoverflow.com/questions/2339735/fabric-password