- 1 year ago
"java.nio.channels.UnresolvedAddressException" while starting kafka server
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The "java.nio.channels.UnresolvedAddressException" error typically occurs when the Kafka server is unable to resolve the hostname or IP address specified in the server configuration. Here are a few things you can check to troubleshoot this issue:
Verify the server configuration:
- Check the
server.properties
file of Kafka to ensure that thelisteners
configuration property is correctly set. It should be set to a valid hostname or IP address and port number combination. For example:listeners=PLAINTEXT://localhost:9092
. - Confirm that the
advertised.listeners
property is correctly set, specifying the external hostname or IP address that clients will use to connect to the Kafka server. For example:advertised.listeners=PLAINTEXT://your.hostname:9092
.
- Check the
Check hostname resolution:
- Ensure that the hostname or IP address specified in the Kafka configuration can be resolved correctly. You can test this by pinging the hostname or IP address from the machine running Kafka to verify that it resolves to the correct IP address.
- If using a hostname, check the DNS configuration on the Kafka server and ensure that it can resolve the hostname to the correct IP address. You may need to update the DNS settings or add an entry to the hosts file (
/etc/hosts
on Unix-like systems orC:\Windows\System32\drivers\etc\hosts
on Windows) to map the hostname to the correct IP address.
Check network connectivity:
- Verify that there are no network connectivity issues between the Kafka server and the client machines. Ensure that firewalls or network security groups are not blocking the Kafka port (e.g., 9092 by default) or the specified listener port.
- Test the network connectivity by attempting to connect to the Kafka server using telnet or another network testing tool. For example:
telnet your.hostname 9092
.
Restart Kafka:
- If you made any configuration changes, restart the Kafka server to apply the changes. Sometimes, a restart can resolve transient hostname resolution issues.
If the issue persists, provide more details about your Kafka server configuration and any relevant error messages or logs to help diagnose the problem more accurately.