How to pass password automatically for rsync SSH command?

Use "sshpass" non-interactive ssh password provider utility

On Ubuntu

 sudo apt-get install sshpass

Command to rsync

 /usr/bin/rsync -ratlz --rsh="/usr/bin/sshpass -p password ssh -o StrictHostKeyChecking=no -l username" src_path  dest_path

You should use a keyfile without passphrase for scripted ssh logins. This is obviously a security risk, take care that the keyfile itself is adequately secured.

Instructions for setting up passwordless ssh access

You can avoid the password prompt on rsync command by setting the environment variable RSYNC_PASSWORD to the password you want to use or using the --password-file option.