I am trying to deploy spring boot application with mysql database on minikube. When I deploy my deployment.ymal file, it is giving communication line failure or connection refused error in spring boot pod's logs.

These are my files:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: springboot-mysql
spec:
  selector:
    matchLabels:
      app: springboot-mysql
  replicas: 3
  template:
    metadata:
      labels:
        app: springboot-mysql
    spec:
      containers:
      - name: springboot-mysql
        image: springbootapp:v3
        ports:
        - containerPort: 8080
        env:
        - name: DB_HOST
          valueFrom:
            configMapKeyRef:
              name: db-conf
              key: host

---


kind: Service
apiVersion: v1
metadata:
  name: springboot-mysql
  labels:
    name: springboot-mysql
spec:
  ports:
    - nodePort: 30163 
      port: 8080      
      targetPort: 8080  
      protocol: TCP
  selector:           
    app: springboot-mysql
  type: NodePort 

Mysql deployment file:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
  labels:
    app: mysql
    tier: database
spec:
  selector:
    matchLabels:
      app: mysql
      tier: database
  strategy: 
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
        tier: database
    spec:
      containers:
      - name: mysql
        image: mysql:5.7
        env: 
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-cred
              key: password 
        
        - name: MYSQL_DATABASE
          valueFrom:
            configMapKeyRef:
              name: db-conf
              key: db_name
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql

      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim: 
          claimName: mysql-pv-claim

---

apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
    tier: database
spec:
  ports:
  - port: 3306
    targetPort: 3306
  selector:
    app: mysql
    tier: database
  clusterIP: None


---

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
  labels:
    name: mysql
    tier: database
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  

Credentials and Config files:

apiVersion: v1
kind: Secret
metadata: 
  name: mysql-cred
data:
  username: root
  password: cm9vdA==

apiVersion: v1
kind: ConfigMap
metadata:
  name: db-conf
data:
  host: mysql
  db_name: demo

This is my spring boot application.properties file:

# DATASOURCE (DataSourceAutoConfiguration & DataSourceProperties)
spring.datasource.url=jdbc:mysql://${DB_HOST}:3306/demo?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC&useLegacyDatetimeCode=false
spring.datasource.username=root
spring.datasource.password=root

# Hibernate

# The SQL dialect makes Hibernate generate better SQL for the chosen database
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect

# Hibernate ddl auto (create, create-drop, validate, update)
spring.jpa.hibernate.ddl-auto = update

logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type=TRACE

This are my error log in spring boot pod's logs

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
	at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) ~[mysql-connector-java-8.0.20.jar!/:8.0.20]
	at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) ~[mysql-connector-java-8.0.20.jar!/:8.0.20]
	at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.20.jar!/:8.0.20]
	at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.20.jar!/:8.0.20]
	at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.20.jar!/:8.0.20]
	at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.20.jar!/:8.0.20]
	at com.zaxxer.hikari.util.DriverDataSource.getConnection(DriverDataSource.java:138) ~[HikariCP-3.4.3.jar!/:na]
	at com.zaxxer.hikari.pool.PoolBase.newConnection(PoolBase.java:358) ~[HikariCP-3.4.3.jar!/:na]
	at com.zaxxer.hikari.pool.PoolBase.newPoolEntry(PoolBase.java:206) ~[HikariCP-3.4.3.jar!/:na]
	at com.zaxxer.hikari.pool.HikariPool.createPoolEntry(HikariPool.java:477) ~[HikariCP-3.4.3.jar!/:na]
	at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:560) ~[HikariCP-3.4.3.jar!/:na]
	at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:115) ~[HikariCP-3.4.3.jar!/:na]
	at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:112) ~[HikariCP-3.4.3.jar!/:na]
	at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator$ConnectionProviderJdbcConnectionAccess.obtainConnection(JdbcEnvironmentInitiator.java:180) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:68) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:237) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.id.factory.internal.DefaultIdentifierGeneratorFactory.injectServices(DefaultIdentifierGeneratorFactory.java:152) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.injectDependencies(AbstractServiceRegistryImpl.java:286) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:243) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:214) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.<init>(InFlightMetadataCollectorImpl.java:176) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:118) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1214) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1245) ~[hibernate-core-5.4.15.Final.jar!/:5.4.15.Final]
	at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58) ~[spring-orm-5.2.6.RELEASE.jar!/:5.2.6.RELEASE]

I am running it on minikube and I am using Ubuntu20.04.