I have solved the issue, I am using centos7 and i had to:
1.) add this in /etc/my.cnf.d/server.cnf
[mysqld]
bind-address=0.0.0.0
[galera]
wsrep_on=ON
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
binlog_format=ROW
wsrep_cluster_address='gcomm://'
wsrep_cluster_name='galera_cluster'
wsrep_node_name='node1'
2.) I had to disable selinux and firewalld to let the other nodes to connect to the cluster. (I know for production uses you should handle the selinux and firewall rules but in my case it was a test on a local machine, so if you use it for prod handle this properly)
3.) in the connecting nodes specify the /etc/my.cnf.d/server.cnf with:
[mysqld]
bind-address=0.0.0.0
[galera]
wsrep_on=ON
wsrep_provider=/usr/lib64/galera/libgalera_smm.so
binlog_format=ROW
wsrep_cluster_address='gcomm://ip_of_the_master,ip_of_other_nodes'
wsrep_cluster_name='galera_cluster'
wsrep_node_name='nodeX'
Then start mysql service.
Now my cluster looks like this:
MariaDB [(none)]> SHOW GLOBAL STATUS LIKE 'wsrep_%';
+------------------------------+-------------------------------------------------------------+
| Variable_name | Value |
+------------------------------+-------------------------------------------------------------+
| wsrep_apply_oooe | 0.000000 |
| wsrep_apply_oool | 0.000000 |
| wsrep_apply_window | 1.000000 |
| wsrep_causal_reads | 0 |
| wsrep_cert_deps_distance | 60.887500 |
| wsrep_cert_index_size | 24 |
| wsrep_cert_interval | 0.000000 |
| wsrep_cluster_conf_id | 73 |
| wsrep_cluster_size | 3 |
| wsrep_cluster_state_uuid | c44d1346-a5c3-11e5-9a68-ca1db8f95be1 |
| wsrep_cluster_status | Primary |
| wsrep_commit_oooe | 0.000000 |
| wsrep_commit_oool | 0.000000 |
| wsrep_commit_window | 1.000000 |
| wsrep_connected | ON |
| wsrep_evs_delayed | |
| wsrep_evs_evict_list | |
| wsrep_evs_repl_latency | 0/0/0/0/0 |
| wsrep_evs_state | OPERATIONAL |
| wsrep_flow_control_paused | 0.000000 |
| wsrep_flow_control_paused_ns | 0 |
| wsrep_flow_control_recv | 0 |
| wsrep_flow_control_sent | 0 |
| wsrep_gcomm_uuid | 3c438933-a727-11e5-b2f2-f659b1338a74 |
| wsrep_incoming_addresses | 100.120.88.245:3306,100.120.88.244:3306,100.120.88.246:3306 |
| wsrep_last_committed | 400 |
| wsrep_local_bf_aborts | 0 |
| wsrep_local_cached_downto | 1 |
| wsrep_local_cert_failures | 0 |
| wsrep_local_commits | 391 |
| wsrep_local_index | 0 |
| wsrep_local_recv_queue | 0 |
| wsrep_local_recv_queue_avg | 0.071429 |
| wsrep_local_recv_queue_max | 2 |
| wsrep_local_recv_queue_min | 0 |
| wsrep_local_replays | 0 |
| wsrep_local_send_queue | 0 |
| wsrep_local_send_queue_avg | 0.000000 |
| wsrep_local_send_queue_max | 1 |
| wsrep_local_send_queue_min | 0 |
| wsrep_local_state | 4 |
| wsrep_local_state_comment | Synced |
| wsrep_local_state_uuid | c44d1346-a5c3-11e5-9a68-ca1db8f95be1 |
| wsrep_protocol_version | 7 |
| wsrep_provider_name | Galera |
| wsrep_provider_vendor | Codership Oy <info@codership.com> |
| wsrep_provider_version | 25.3.9(r3387) |
| wsrep_ready | ON |
| wsrep_received | 182 |
| wsrep_received_bytes | 17414 |
| wsrep_repl_data_bytes | 52304 |
| wsrep_repl_keys | 1183 |
| wsrep_repl_keys_bytes | 18664 |
| wsrep_repl_other_bytes | 0 |
| wsrep_replicated | 400 |
| wsrep_replicated_bytes | 96568 |
| wsrep_thread_count | 2 |
+------------------------------+-------------------------------------------------------------+
