Policy-mariadb connection intermittently fails from PF components

[2021-09-08T11:58:12.268+00:00|ERROR|PdpStatusMessageHandler|DMAAP-source-POLICY-HEARTBEAT] Failed connecting to database provider
javax.persistence.PersistenceException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.7.8.v20201217-ecdf3c32c4): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLNonTransientConnectionException: Could not connect to address=(host=policy-mariadb)(port=3306)(type=master) : Socket fail to connect to host:policy-mariadb, port:3306. Connection refused (Connection refused)
Error Code: -1
        at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:857)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.getAbstractSession(EntityManagerFactoryDelegate.java:222)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryDelegate.createEntityManagerImpl(EntityManagerFactoryDelegate.java:330)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManagerImpl(EntityManagerFactoryImpl.java:350)
        at org.eclipse.persistence.internal.jpa.EntityManagerFactoryImpl.createEntityManager(EntityManagerFactoryImpl.java:313)
        at org.onap.policy.models.dao.impl.DefaultPfDao.getEntityManager(DefaultPfDao.java:155)
        at org.onap.policy.models.dao.impl.DefaultPfDao.genericGet(DefaultPfDao.java:439)
        at org.onap.policy.models.dao.impl.DefaultPfDao.get(DefaultPfDao.java:412)
        at org.onap.policy.models.dao.impl.DefaultPfDao.getFiltered(DefaultPfDao.java:385)
        at org.onap.policy.models.pdp.persistence.provider.PdpProvider.getFilteredPdpGroups(PdpProvider.java:84)
        at org.onap.policy.models.provider.impl.DatabasePolicyModelsProviderImpl.getFilteredPdpGroups(DatabasePolicyModelsProviderImpl.java:219)
        at org.onap.policy.pap.main.comm.PdpStatusMessageHandler.handlePdpHeartbeat(PdpStatusMessageHandler.java:231)
        at org.onap.policy.pap.main.comm.PdpStatusMessageHandler.handlePdpStatus(PdpStatusMessageHandler.java:115)
        at org.onap.policy.pap.main.comm.PdpHeartbeatListener.onTopicEvent(PdpHeartbeatListener.java:47)
        at org.onap.policy.pap.main.comm.PdpHeartbeatListener.onTopicEvent(PdpHeartbeatListener.java:36)
        at org.onap.policy.common.endpoints.listeners.RequestIdDispatcher.offerToListener(RequestIdDispatcher.java:151)
        at org.onap.policy.common.endpoints.listeners.RequestIdDispatcher.onTopicEvent(RequestIdDispatcher.java:124)
        at org.onap.policy.common.endpoints.listeners.ScoListener.onTopicEvent(ScoListener.java:74)
        at org.onap.policy.common.endpoints.listeners.MessageTypeDispatcher.onTopicEvent(MessageTypeDispatcher.java:96)
        at org.onap.policy.common.endpoints.listeners.JsonListener.onTopicEvent(JsonListener.java:60)
        at org.onap.policy.common.endpoints.event.comm.bus.internal.TopicBase.broadcast(TopicBase.java:169)
        at org.onap.policy.common.endpoints.event.comm.bus.internal.SingleThreadedBusTopicSource.fetchAllMessages(SingleThreadedBusTopicSource.java:251)
        at org.onap.policy.common.endpoints.event.comm.bus.internal.SingleThreadedBusTopicSource.run(SingleThreadedBusTopicSource.java:234)
        at java.base/java.lang.Thread.run(Unknown Source)