After installation of two separate controller nodes, how to setup those as standby

I try to setup controller standby using http://docs.openstack.org/ha-guide/shared-database-manage.html (openstack ha document).

I'm using centos7 controllers mariadb version 10.1.16 galera 25.3.5

But in the phase of db cluster, after db cluster service started the cluster size remains 0 in database.

After i changed configuration of my.cnf file as below, db cluster is ready to sync

For controller1

[mysqld]
query_cache_size=0
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
query_cache_type=0
bind-address=10.10.100.240

# Galera Provider Configuration
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
#wsrep_provider_options="gcache.size=32G"

# Galera Cluster Configuration
wsrep_cluster_name="cluster1"
wsrep_cluster_address="gcomm://"

# Galera Synchronization Congifuration
wsrep_sst_method=rsync


# Galera Node Configuration
wsrep_node_address="10.10.100.240"
wsrep_node_name="node1"
wsrep_on=ON

For controller2

[mysqld]
query_cache_size=0
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
query_cache_type=0
bind-address=10.10.100.241

# Galera Provider Configuration
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
#wsrep_provider_options="gcache.size=32G"

# Galera Cluster Configuration
wsrep_cluster_name="cluster1"
wsrep_cluster_address="gcomm://10.10.100.240,10.10.100.241"

# Galera Synchronization Congifuration
wsrep_sst_method=rsync
#wsrep_sst_auth=user:pass

# Galera Node Configuration
wsrep_node_address="10.10.100.241"
wsrep_node_name="node2"
wsrep_on=ON

But controller1 db is replicated to controller2, both db has same identical db of controller1 only.

controller1 working fine after db replication but controller2 not due to no db availed.

whats wrong in my setup, is there any other way to setup ha standby controller.