centos - 关于安装greenplum过程中的问题

1.系统环境和形相应软件版本: centos6.5 green-plum的版本是4.3.5.2

2.在安装过程中:
1)已经修改了内核参数:

    net.ipv4.ip_forward = 0
    net.ipv4.conf.default.rp_filter = 1
    net.ipv4.conf.default.accept_source_route = 0
    kernel.sysrq = 1
    kernel.core_uses_pid = 1
    net.ipv4.tcp_syncookies = 1
    kernel.msgmnb = 65536
    kernel.msgmax = 65536
    kernel.msgmni = 2048
    kernel.shmmax = 500000000
    kernel.shmmni = 4096
    kernel.shmall = 4000000000
    net.ipv4.tcp_tw_recycle = 1
    net.ipv4.tcp_max_syn_backlog = 4096
    net.ipv4.ip_local_port_range = 1025 65535
    net.core.netdev_max_backlog = 10000
    vm.overcommit_memory = 2
    net.ipv4.conf.all.arp_filter = 1
    net.core.rmem_max = 2097152
    net.core.wmem_max = 2097152

2)修改了软硬连接数:
  * soft nofile 65536
  * hard nofile 65536
  * soft nproc 131072 
 * hard nproc 131072
 

3)关闭防火墙和selinux.
4)host中已将修好了配置:

 192.168.9.173    ljlj-master     mt
 192.168.9.153    ljlj-slave      st
 

5)安装greenplum过程没有问题,已经将其安装到/usr/local/greenplum中了,

自己尽力一个conf文件放hostfile,里面内容是: 
mt
st

6)/usr/local/greenplum所有者和所有者组都已经设定为gpadmin用户(该用户提前被建立)
7)切换到gpadmin用户,执行 gpssh-exkeys -f /usr/local/greenplum/conf/hostfile

在此处出现报错:
[STEP 1 of 5] create local ID and authorize on local host
... /home/gpadmin/.ssh/id_rsa file exists ... key generation skipped

[STEP 2 of 5] keyscan all hosts and update known_hosts file

[STEP 3 of 5] authorize current user on remote hosts
... send to st
*
* Enter password for st:
[ERROR st] Host key for server st does not match!
*
* Enter password for st:
[ERROR st] Host key for server st does not match!
*
* Enter password for st:

在这里输入的st端root的密码,但是它一直报错Host key for server st does not match!

但是当我ping st是通的
PING ljlj-slave (192.168.9.153) 56(84) bytes of data.
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=1 ttl=64 time=1.08 ms
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=2 ttl=64 time=0.189 ms
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=3 ttl=64 time=0.187 ms
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=4 ttl=64 time=0.184 ms
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=5 ttl=64 time=0.188 ms
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=6 ttl=64 time=0.130 ms
64 bytes from ljlj-slave (192.168.9.153): icmp_seq=7 ttl=64 time=0.186 ms
^C
--- ljlj-slave ping statistics ---
7 packets transmitted, 7 received, 0% packet loss, time 6462ms
rtt min/avg/max/mdev = 0.130/0.307/1.089/0.320 ms

但是当我手动添加:gpssh-exkeys -h 192.168.9.153
[STEP 1 of 5] create local ID and authorize on local host
... /home/gpadmin/.ssh/id_rsa file exists ... key generation skipped

[STEP 2 of 5] keyscan all hosts and update known_hosts file

[STEP 3 of 5] authorize current user on remote hosts
... send to 192.168.9.153
*
* Enter password for 192.168.9.153:
[ERROR 192.168.9.153] bad password
*
* Enter password for 192.168.9.153:
[ERROR 192.168.9.153] bad password
*
此处又报密码不对,排除密码输入错误的情况(此处也是输入的root密码)

求大神们,解释一下这是什么原因造成的,求解答!谢谢了,大神们!!!