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On AWS, I had EC2 mongodb cluster on a VPC and tried to use MSKConnect to capture change stream and publish to MSK on another VPC. Both VPCs can reach each others via TransitG​W.

I also had EC2 on the same subnet as MSK. The subnet was allowed to security group of the mongodb servers. Then, from EC2, I could telnet to the mongodb servers.

However, I couldn't connect from MSKConnect to mongodb servers and got error UnknownHostException.

error logs

[Worker-0a8d71eb5ca43ce7d] [2023-08-21 09:59:24,914] INFO Opened connection [connectionId{localValue:40, serverValue:14772638}] to INTERNAL_IP (org.mongodb.driver.connection:71)
[Worker-0a8d71eb5ca43ce7d] [2023-08-21 09:59:24,912] INFO Adding discovered server mongo2.co.th:27017 to client view of cluster (org.mongodb.driver.cluster:71)
[Worker-0a8d71eb5ca43ce7d] [2023-08-21 09:59:24,921] INFO Exception in monitor thread while connecting to server mongo2.co.th:27017 (org.mongodb.driver.cluster:76)
[Worker-0a8d71eb5ca43ce7d] com.mongodb.MongoSocketException: mongo2.co.th
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.ServerAddress.getSocketAddresses(ServerAddress.java:217)
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.internal.connection.SocketStream.initializeSocket(SocketStream.java:75)
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:65)
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:180)
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.lookupServerDescription(DefaultServerMonitor.java:193)
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:157)
[Worker-0a8d71eb5ca43ce7d]  at java.base/java.lang.Thread.run(Thread.java:829)
[Worker-0a8d71eb5ca43ce7d] Caused by: java.net.UnknownHostException: mongo2.co.th
[Worker-0a8d71eb5ca43ce7d]  at java.base/java.net.InetAddress$CachedAddresses.get(InetAddress.java:797)
[Worker-0a8d71eb5ca43ce7d]  at java.base/java.net.InetAddress.getAllByName0(InetAddress.java:1524)
[Worker-0a8d71eb5ca43ce7d]  at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1382)
[Worker-0a8d71eb5ca43ce7d]  at java.base/java.net.InetAddress.getAllByName(InetAddress.java:1306)
[Worker-0a8d71eb5ca43ce7d]  at com.mongodb.ServerAddress.getSocketAddresses(ServerAddress.java:209)
[Worker-0a8d71eb5ca43ce7d]  ... 6 more
OneCricketeer
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Pakorn K
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  • Removing the Kafka tags since this is a generic DNS error to be solved in your network, so mostly unrelated to the application itself. I suggest contacting MSK support to see how DNS resolution is configured – OneCricketeer Aug 23 '23 at 03:39

0 Answers0