linux ssh 配置登录问题

我在centos6.5 的几台机器上新建了用户hadoop,我在配置ssh的时候每次都需要输入密码。
1） .ssh 文件夹的权限我已经修改成了700，authorized_keys文件权限也是600 还是不行。
2） 防火墙,selinux 都关闭了也不行。
3） restorecon 也不行。
4） 调试模式
[hadoop@namenode ~]$ ssh -v datanode1
OpenSSH_5.3p1, OpenSSL 1.0.1e-fips 11 Feb 2013
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to datanode1 [172.16.22.122] port 22.
debug1: Connection established.
debug1: identity file /home/hadoop/.ssh/identity type -1
debug1: identity file /home/hadoop/.ssh/identity-cert type -1
debug1: identity file /home/hadoop/.ssh/id_rsa type -1
debug1: identity file /home/hadoop/.ssh/id_rsa-cert type -1
debug1: identity file /home/hadoop/.ssh/id_dsa type -1
debug1: identity file /home/hadoop/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'datanode1' is known and matches the RSA host key.
debug1: Found key in /home/hadoop/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Trying private key: /home/hadoop/.ssh/identity
debug1: Trying private key: /home/hadoop/.ssh/id_rsa
debug1: Trying private key: /home/hadoop/.ssh/id_dsa
debug1: Next authentication method: password
hadoop@datanode1's password:

没有什么问题。