Clustercontrol - what is checked during deployment?

Hi,

i'm trying to install a Codership Galera Cluster(3-nodes). Due to no internet connection i've already installed all 3 nodes with the same actual rpms

galera-3-25.3.17-2.el6.x86_64.rpm
mysql-wsrep-5.6-5.6.31-25.16.el6.x86_64.rpm (client, server, libs etc)
percona-xtrabackup-24-2.4.4-1.el6.x86_64.rpm

my.cnf
[mysqld]
datadir=/var/lib/mysql/data
socket=/var/lib/mysql/mysql.sock
user=mysql

all root user having the same pwd

then I'm trying to add a new Galera Codership 5.6 Cluster (passwordless access works)
- entering os-user
- disabeling installation
- disabeling selinux/firewall
- entering IPs / root-pwd / data-path etc
- pressing "deploy"

Watching the log:
Installation/Deployment always stops at first node checking mySQL and XtraBackup

439 - 10.225.2.193: Verifying helper packages (checking 'socat').
440 - vendor='rhel' release='6' type='redhat'
441 - Using template: my.cnf.galera
442 - mysql_server_id is not specified in the job, using '1'.
443 - 10.225.2.193: Detecting total memory.
444 - 10.225.2.193: Detected memory: 62532 MB
445 - 10.225.2.193: Checking free-disk space of /var/lib/mysql/data
446 - 10.225.2.193: Detected free disk space: 286715 MB. Total disk space: 302376 MB.
447 - 10.225.2.193: Prepare MySQL environment (user/group)
448 - 10.225.2.193: Using existing MySQL packages.
449 - 10.225.2.193: Verifying the MySQL installation.
450 - 10.225.2.193: Verifying the xtrabackup installation.
451 - 10.225.2.193: percona-xtrabackup is not installed.
452 - 10.225.2.193: Setup server failure, see the previous msgs.
Job failed.

What's checked in these steps? What am I missing?
Is there any Step-by-Step Documentation on this?

Many thx to you all