I have frontend container running with below php code;

<?php
$hn=file_get_contents('/var/secrets/hostname.txt');
$hn=str_replace("\n", "", $hn);
$pass=file_get_contents('/var/secrets/password.txt');
$pass=str_replace("\n", "", $pass);
$cname=$_POST['name'];
$email=$_POST['email'];
$hostname=$hn;
$username='root';
$password=$pass;
$dbname='test';
$usertable='testuser';
$con=mysqli_connect($hostname,$username, $password) OR DIE ('Unable to connect to database! Please try again later.');
mysqli_select_db($con,$dbname);
$query = "select * from testuser";
$result = $con->query($query) or die("Not Updated!");
while($row = $result->fetch_assoc()) {
        echo "<tr><td> " . $row["name"] . "<td> " . $row["email"] . "</tr> ";
}
$con->close();
?>

I have hostname name and password saved in text file as mentioned above on frontend container. I have metioned hostname as SeriveName. Please find below sample backend service, here backend service name is "userdatabase-service". Same I have mentioned in hostname.txt on frontend container.

    apiVersion: v1
kind: Service
metadata:
  creationTimestamp: 2018-11-13T12:01:25Z
  labels:
    app: userdatabase
  name: userdatabase-service
  namespace: default
  resourceVersion: "32448"
  selfLink: /api/v1/namespaces/default/services/userdatabase-service
  uid: d85cf471-e73b-11e8-8506-42010aa60fca
spec:
  clusterIP: 10.7.255.80
  externalTrafficPolicy: Cluster
  ports:
  - nodePort: 30198
    port: 80
    protocol: TCP
    targetPort: 3306
  selector:
    app: userdatabase
  sessionAffinity: None
  type: LoadBalancer
status:
  loadBalancer:
    ingress:
    - ip: 35.228.105.176

But while accessing frontend service which pulls record from database gives message: Unable to connect to database! Please try again later.

I tried with Ingress Ip but still it gives same error. Can you please guide here? Regards, Vikas