my ssh is ok but masterha_check_ssh is fail my environment is vmware12 + centos6.6 + mysql5.5 + mha4mysql-manager-0.53-0.noarch.rpm + mha4mysql-node-0.53-0.noarch.rpm 

my structure is one master three slaves

master  192.168.233.135 node
slave1  192.168.233.132 node
slave2  192.168.233.133 node
slave3  192.168.233.134 node + manager


My root@slave3 to root@master is OK!

[root@slave3 ~]# ssh root@master
Last login: Fri Jun  3 08:03:21 2016 from 192.168.233.134

[root@slave3 ~]# ssh root@192.168.233.135
Last login: Fri Jun  3 08:38:00 2016 from 192.168.233.134


but when I use masterha_check_ssh it fails

[root@slave3 ~]# /usr/bin/masterha_check_ssh --conf=/etc/app1.cnf
Tue May 31 17:08:23 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue May 31 17:08:23 2016 - [info] Reading application default configurations from /etc/app1.cnf..
Tue May 31 17:08:23 2016 - [info] Reading server configurations from /etc/app1.cnf..
Tue May 31 17:08:23 2016 - [info] Starting SSH connection tests..
Tue May 31 17:08:26 2016 - [error][/usr/lib64/perl5/vendor_perl/MHA/SSHCheck.pm, ln63] 
Tue May 31 17:08:25 2016 - [debug]  Connecting via SSH from root@slave3(192.168.233.134:22) to root@master(192.168.233.135:22)..
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
Tue May 31 17:08:26 2016 - [error][/usr/lib64/perl5/vendor_perl/MHA/SSHCheck.pm, ln107] SSH connection from root@slave3(192.168.233.134:22) to root@master(192.168.233.135:22) failed!
Tue May 31 17:08:28 2016 - [debug] 
Tue May 31 17:08:24 2016 - [debug]  Connecting via SSH from root@slave1(192.168.233.132:22) to root@master(192.168.233.135:22)..
Tue May 31 17:08:26 2016 - [debug]   ok.
Tue May 31 17:08:26 2016 - [debug]  Connecting via SSH from root@slave1(192.168.233.132:22) to root@slave2(192.168.233.133:22)..
Tue May 31 17:08:26 2016 - [debug]   ok.
Tue May 31 17:08:26 2016 - [debug]  Connecting via SSH from root@slave1(192.168.233.132:22) to root@slave3(192.168.233.134:22)..
Tue May 31 17:08:28 2016 - [debug]   ok.
Tue May 31 17:08:28 2016 - [debug] 
Tue May 31 17:08:23 2016 - [debug]  Connecting via SSH from root@master(192.168.233.135:22) to root@slave1(192.168.233.132:22)..
Tue May 31 17:08:25 2016 - [debug]   ok.
Tue May 31 17:08:25 2016 - [debug]  Connecting via SSH from root@master(192.168.233.135:22) to root@slave2(192.168.233.133:22)..
Tue May 31 17:08:26 2016 - [debug]   ok.
Tue May 31 17:08:26 2016 - [debug]  Connecting via SSH from root@master(192.168.233.135:22) to root@slave3(192.168.233.134:22)..
Tue May 31 17:08:28 2016 - [debug]   ok.
Tue May 31 17:08:28 2016 - [debug] 
Tue May 31 17:08:24 2016 - [debug]  Connecting via SSH from root@slave2(192.168.233.133:22) to root@master(192.168.233.135:22)..
Tue May 31 17:08:26 2016 - [debug]   ok.
Tue May 31 17:08:26 2016 - [debug]  Connecting via SSH from root@slave2(192.168.233.133:22) to root@slave1(192.168.233.132:22)..
Tue May 31 17:08:27 2016 - [debug]   ok.
Tue May 31 17:08:27 2016 - [debug]  Connecting via SSH from root@slave2(192.168.233.133:22) to root@slave3(192.168.233.134:22)..
Tue May 31 17:08:28 2016 - [debug]   ok.
SSH Configuration Check Failed!
 at /usr/bin/masterha_check_ssh line 44


and my /etc/app1.cnf is 

[root@slave3 ~]# cat /etc/app1.cnf

  [server default]
  user=root
  password=123456
  ssh_user=root
  master_binlog_dir= /data/mysql3306/logs/
  remote_workdir=/tmp
  secondary_check_script= /usr/bin/masterha_secondary_check -s slave3-s slave2
  ping_interval=3
  master_ip_failover_script=/script/masterha/master_ip_failover
  shutdown_script= /script/masterha/power_manager
  report_script= /script/masterha/send_master_failover_mail
  manager_workdir=/var/log/masterha/app1
  manager_log=/var/log/masterha/app1/app1.log

  [server1]
  hostname=master

  [server2]
  hostname=slave1
  candidate_master=1

  [server3]
  hostname=slave2
  candidate_master=1  

  [server4]
  hostname=slave3
  no_master=1
I just encountered the above error and discovered where I got it wrong. 

The content of id_rsa.pub file on slave3 (which is your manager node) also but be copied over to your authorized_keys file to enable passwordless ssh into slave3. Once I copied public ssh key (id_rsa.pub) into authorized_key, the error was gone. To confirm this, you should run ssh root@192.168.233.134 on slave3 to confirm you are able to ssh into slave3 as root without a password.