MongoSocketException or UnknownHostException - while connecting to MongoAtlas mongo cluster

Question

I am trying to connect cluster in Mongo Atlas.

The access permission is already given to the cluster for all IP's in MongoDB Atlas.

The application I have is SpringBoot application.

• Java-11
• SpringBoot - 2.5.5
• MongoDB 6+

The expcetion while making the connection is:

Timed out after 30000 ms while waiting to connect. Client view of cluster state is 
{type=UNKNOWN, servers=[{address=CusterName:27017, type=UNKNOWN, state=CONNECTING, 
exception={com.mongodb.MongoSocketException: CusterName}, caused by {java.net.UnknownHostException: CusterName}}]; 
nested exception is com.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting to connect. 
Client view of cluster state is {type=UNKNOWN, servers=[{address=CusterName:27017, type=UNKNOWN, state=CONNECTING, 
exception={com.mongodb.MongoSocketException: CusterName}, caused by {java.net.UnknownHostException: CusterName}}]

The java class which I am using to create a pool is:

import com.mongodb.*;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.connection.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDatabaseFactory;
import org.springframework.data.mongodb.MongoTransactionManager;
import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

@Configuration
public class MongoConnectionPool {

    @Bean
    @Autowired
    public MongoDatabaseFactory mongoFactory() {

        List<ServerAddress> serverAddresses = new ArrayList<>();

        String address = "<clusterName>:<port>"
        String[] hostAndPort = address.split(":");
        String host = hostAndPort[0];
        Integer port = Integer.parseInt(hostAndPort[1]);
        ServerAddress serverAddress = new ServerAddress(host, port);
        serverAddresses.add(serverAddress);
            
        ConnectionString connUrl = new ConnectionString("mongodb+srv://<username>:<password>@<clusterName>/<databaseName>");
        ConnectionPoolSettings poolSettings = ConnectionPoolSettings.builder()
                .maxWaitTime(100, TimeUnit.MILLISECONDS)
                .maxConnectionIdleTime(50, TimeUnit.MILLISECONDS)
                .maxConnectionLifeTime(30, TimeUnit.MILLISECONDS)
                .maxSize(12)
                .minSize(2)
                .build();
        ServerSettings serverSettings = ServerSettings.builder()
                .heartbeatFrequency(300, TimeUnit.MILLISECONDS)
                .minHeartbeatFrequency(100, TimeUnit.MILLISECONDS)
                .build();
        ClusterSettings clusterSettings = ClusterSettings.builder()
                .hosts(serverAddresses)
                .localThreshold(200, TimeUnit.MILLISECONDS)
                .serverSelectionTimeout(250, TimeUnit.MILLISECONDS)
                .requiredClusterType(ClusterType.REPLICA_SET)
                .mode(ClusterConnectionMode.SINGLE)
                .requiredReplicaSetName("rs0")
                .build();
        SocketSettings socketSettings = SocketSettings.builder()
                .connectTimeout(100, TimeUnit.MILLISECONDS)
                .readTimeout(50, TimeUnit.MILLISECONDS)
                .build();
        SslSettings sslSettings = SslSettings.builder()
                .enabled(false)
                .invalidHostNameAllowed(false)
                .build();
        MongoClientSettings settings = MongoClientSettings.builder()
                .applyConnectionString(connUrl)
                .applyToClusterSettings(builder -> builder.applySettings(clusterSettings))
                .applyToConnectionPoolSettings(builder -> builder.applySettings(poolSettings))
                .applyToServerSettings(builder -> builder.applySettings(serverSettings))
                .applyToSocketSettings(builder -> builder.applySettings(socketSettings))
                .applyToSslSettings(builder -> builder.applySettings(sslSettings))
                .readPreference(ReadPreference.primary())
                .build();

        MongoClient mongoClient = MongoClients.create(settings);
        return new SimpleMongoClientDatabaseFactory(mongoClient, "<databaseName>");
    }

    @Bean
    MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
        return new MongoTransactionManager(dbFactory);
    }

}

I am not sure, why it is not connecting to the database cluster. Any suggestions?

Thanks,

Atul

Answer 1

I am able to solve the issue. I have commented couple of settings and then its working fine.

import com.mongodb.*;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.connection.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDatabaseFactory;
import org.springframework.data.mongodb.MongoTransactionManager;
import org.springframework.data.mongodb.core.SimpleMongoClientDatabaseFactory;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

@Configuration
public class MongoConnectionPool {

    @Bean
    @Autowired
    public MongoDatabaseFactory mongoFactory() {

        List<ServerAddress> serverAddresses = new ArrayList<>();

        String address = "<clusterName>:<port>"
        String[] hostAndPort = address.split(":");
        String host = hostAndPort[0];
        Integer port = Integer.parseInt(hostAndPort[1]);
        ServerAddress serverAddress = new ServerAddress(host, port);
        serverAddresses.add(serverAddress);
            
        ConnectionString connUrl = new ConnectionString("mongodb+srv://<username>:<password>@<clusterName>/<databaseName>");
        ConnectionPoolSettings poolSettings = ConnectionPoolSettings.builder()
                .maxWaitTime(100, TimeUnit.MILLISECONDS)
                .maxConnectionIdleTime(50, TimeUnit.MILLISECONDS)
                .maxConnectionLifeTime(30, TimeUnit.MILLISECONDS)
                .maxSize(12)
                .minSize(2)
                .build();
        ServerSettings serverSettings = ServerSettings.builder()
                .heartbeatFrequency(300, TimeUnit.MILLISECONDS)
                .minHeartbeatFrequency(100, TimeUnit.MILLISECONDS)
                .build();
        /*ClusterSettings clusterSettings = ClusterSettings.builder()
                .hosts(serverAddresses)
                .localThreshold(200, TimeUnit.MILLISECONDS)
                .serverSelectionTimeout(250, TimeUnit.MILLISECONDS)
                .requiredClusterType(ClusterType.REPLICA_SET)
                .mode(ClusterConnectionMode.SINGLE)
                .requiredReplicaSetName("rs0")
                .build();*/
        SocketSettings socketSettings = SocketSettings.builder()
                .connectTimeout(100, TimeUnit.MILLISECONDS)
                .readTimeout(50, TimeUnit.MILLISECONDS)
                .build();
        /*SslSettings sslSettings = SslSettings.builder()
                .enabled(false)
                .invalidHostNameAllowed(false)
                .build();*/
        MongoClientSettings settings = MongoClientSettings.builder()
                .applyConnectionString(connUrl)
                //.applyToClusterSettings(builder -> builder.applySettings(clusterSettings))
                .applyToConnectionPoolSettings(builder -> builder.applySettings(poolSettings))
                .applyToServerSettings(builder -> builder.applySettings(serverSettings))
                .applyToSocketSettings(builder -> builder.applySettings(socketSettings))
                //.applyToSslSettings(builder -> builder.applySettings(sslSettings))
                .readPreference(ReadPreference.primary())
                .build();

        MongoClient mongoClient = MongoClients.create(settings);
        return new SimpleMongoClientDatabaseFactory(mongoClient, "<databaseName>");
    }

    @Bean
    MongoTransactionManager transactionManager(MongoDatabaseFactory dbFactory) {
        return new MongoTransactionManager(dbFactory);
    }

}

I do not know what the issue is with ClusterSettings and SSLSettings code. I guess it is a bug(not sure)

Thanks,

Atul