I have one service on 2 node rac. Service has one preferred node and one available node. My problem

I have one service on 2 node rac. Service has one preferred node and one available node.  My problem is connections are being made on both the instances instead of one node.

[oracle@dm02dbadm01 ~]$ srvctl status service -d ECGGIS5P -s ECGGIS5P_12C

Service ECGGIS5P_12c is running on instance(s) ECGGIS5P2

[oracle@dm02dbadm01 ~]$ srvctl config service -d ECGGIS5P -s ECGGIS5P_12C

Service name: ECGGIS5P_12c

Service is enabled

Server pool: ECGGIS5P_ECGGIS5P_12c

Cardinality: 1

Disconnect: false

Service role: PRIMARY

Management policy: AUTOMATIC

DTP transaction: false

AQ HA notifications: false

Global: false