ssh a host without input the password

$ vim /home/wangzheng/.ssh/config
Host 10.103.xx.xx
  HostName 10.103.xx.xx

User root 
  Port 22022 
$ ssh 10.103.xx.xx

The authenticity of host '[10.103.xx.xx]:22022 ' can't be established. RSA key fingerprint is xxxxx:7e. Are you sure you want to continue connecting (yes/no)? yes 
Warning: Permanently added '[10.103.xx.xx]:22022' (RSA) to the list of known hosts. root@10.103.xx.xx's password: 

$ ssh-copy-id --help 
Usage: /usr/bin/ssh-copy-id [-i [identity_file]] [user@]machine 
$ ssh-copy-id 10.103.xx.xx
 root@10.103.xx.xx's password:
 Now try logging into the machine, with "ssh '10.103.xx.xx'", and check in: ~/.ssh/authorized_keys to make sure we haven't added extra keys that you weren't expecting.
$ ssh 10.103.xx.xx 
Last login: Mon Jun 16 10:51:35 2014 from 10.10.106.64 tty:[3] jobs:[0] cwd:[~] ip:[10.103.xx.xx]