How to connect to k8s mongodb endpoint from spring boot

Question

I have a spring boot app which deployed in Kubernetes and need to connect to mongodb server hosted outside of the cluster. As per the Kubernetes specified in https://cloud.google.com/blog/products/gcp/kubernetes-best-practices-mapping-external-services , i have created Kubernetes service and endpoint for my mongodb server. Now my spring boot application need to connect to this end point. I have tried following

-- adding uri to application.properties

spring.data.mongodb.uri=mongodb://mongo

-- explicitly defining mongodb client from spring

@Configuration
@Slf4j
public class AppConfig {

@Autowired
DiscoveryClient discoveryClient;

  public @Bean MongoClient mongoClient() {
      MongoClientURI mongoClientURI = new MongoClientURI("mongodb://mongo");
      return new MongoClient(mongoClientURI);
  }
}

But my application keep throwing error

com.mongodb.MongoSocketException: mongo: Try again
at com.mongodb.ServerAddress.getSocketAddresses(ServerAddress.java:211) ~[mongo-java-driver-3.11.2.jar:na]
at com.mongodb.internal.connection.SocketStream.initializeSocket(SocketStream.java:75) ~[mongo-java-driver-3.11.2.jar:na]
at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:65) ~[mongo-java-driver-3.11.2.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:128) ~[mongo-java-driver-3.11.2.jar:na]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:117) ~[mongo-java-driver-3.11.2.jar:na]
at java.base/java.lang.Thread.run(Thread.java:835) ~[na:na]
Caused by: java.net.UnknownHostException: mongo: Try again
at java.base/java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method) ~[na:na]
at java.base/java.net.InetAddress$PlatformNameService.lookupAllHostAddr(InetAddress.java:929) ~[na:na]
at java.base/java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1515) ~[na:na]
at java.base/java.net.InetAddress$NameServiceAddresses.get(InetAddress.java:848) ~[na:na]
at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1505) ~[na:na]
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1364) ~[na:na]
at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1298) ~[na:na]
at com.mongodb.ServerAddress.getSocketAddresses(ServerAddress.java:203) ~[mongo-java-driver-3.11.2.jar:na]
... 5 common frames omitted

I have following dependencies in my project

  <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-kubernetes-core</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-kubernetes-discovery</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-kubernetes-config</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-kubernetes-ribbon</artifactId>
    </dependency>

score 0 · Answer 1 · answered Feb 11 '20 at 07:29

After little searching i was able to connect as following,

public @Bean MongoClient mongoClient() {
    List<ServiceInstance> mongo = discoveryClient.getInstances("mongo");
    List<ServerAddress> mongoAddressList = new ArrayList<>();
    for (ServiceInstance serviceInstance : mongo) {
        ServerAddress serverAddress = new ServerAddress(serviceInstance.getHost());
        mongoAddressList.add(serverAddress);
    }
    MongoClientURI mongoClientURI = new MongoClientURI("mongodb://mongo");
    return new MongoClient(mongoAddressList);
}

This is working but don't know if this is a best way to do this.

How to connect to k8s mongodb endpoint from spring boot

1 Answers1