Error connecting to postgres pod from jasper pod - Kubernetes

I am trying to implement Kubernetes with Jaspersoft Community Edition V7.5 but facing issues in connecting PostgreSQL POD from Jasper Pod. The details are described below:

For postgres:

configmap/postgres-config created

service/postgresql created

deployment.apps/postgresql created

persistentvolume/postgres-pv-volume-test created

persistentvolumeclaim/postgres-jasper-claim created

For jasper:

configmap/jasper-config created

service/jasperserver created

The error I faced is shown below:

do-install-upgrade-test:

[echo] Checking DBMS host and port:

[echo] About to validate port: postgresql:5432

BUILD FAILED

/usr/src/jasperreports-server/buildomatic/bin/validation.xml:487: The following error occurred while executing this line:

/usr/src/jasperreports-server/buildomatic/bin/validation.xml:244: The following error occurred while executing this line:

/usr/src/jasperreports-server/buildomatic/bin/validation.xml:293: Error: port 5432 is not reachable at host postgresql