Kafka Connect running out of heap space

Even I was facing the issue could not start my producer and consumer for a given topic. Also deleted all unnecessary log files and topics.Even though that's not related to the issue.

Changing the kafka-run-class.sh did not work for me. I changed the below files



and stopped getting OOM error. Both consumer and producer worked fine after this.

Increased the size to KAFKA_HEAP_OPTS="-Xmx1G" was 512m earlier.

I found another cause of this issue this morning. I was seeing this same exception except that I'm not using SSL and my messages are very small. The issue in my case turned out to be a misconfigured bootstrap-servers url. If you configure that URL to be a server and port that is open but incorrect, you can cause this same exception. The Kafka folks are aware of the general issue and are tracking it here: https://cwiki.apache.org/confluence/display/KAFKA/KIP-498%3A+Add+client-side+configuration+for+maximum+response+size+to+protect+against+OOM

When you have Kafka problems with

java.lang.OutOfMemoryError: Java heap space

it doesn't necessarily mean that it's a memory problem. Several Kafka admin tools like kafka-topics.sh will mask the true error with this when trying to connect to an SSL PORT. The true (masked) error is SSL handshake failed !

See this issue: https://issues.apache.org/jira/browse/KAFKA-4090

The solution is to include a properties file in your command (for kafka-topics.sh this would be --command-config) and to absolutely include this line:


You can control the max and initial heap size by setting the KAFKA_HEAP_OPTS environment variable.

The following example sets a starting size of 512 MB and a maximum size of 1 GB:

KAFKA_HEAP_OPTS="-Xms512m -Xmx1g" connect-standalone connect-worker.properties connect-s3-sink.properties

When running a Kafka command such as connect-standalone, the kafka-run-class script is invoked, which sets a default heap size of 256 MB in the KAFKA_HEAP_OPTS environment variable if it is not already set.