Configuring logging

All logs are sent to stdout by default. You can change this by extending the images.

log4j Log Levels

To change the default logging levels or add new logging levels:

1. Change the {COMPONENT}_LOG4J_ROOT_LOGLEVEL to change rootLogger loglevel.
2. Add or override default loggers by using {COMPONENT}_LOG4J_LOGGERS environment variable. This variable accepts the comma separated values of the logger config. For example, to override the log levels of controller and request loggers , use KAFKA_LOG4J_LOGGERS="kafka.controller=WARN,kafka.foo.bar=DEBUG"
3. To change the logging levels for the tools, use the {COMPONENT}_LOG4J_TOOLS_ROOT_LOGLEVEL.

Note: The Component Names table lists the {COMPONENT} names for each component.

A full example for Kafka is shown below:

docker run -d \
  --name=kafka-log-example \
  --net=host
  -e KAFKA_BROKER_ID=1 \
  -e KAFKA_ZOOKEEPER_CONNECT=localhost:32181/jmx \
  -e KAFKA_ADVERTISED_LISTENERS=PLAINTEXT://localhost:39092 \
  -e KAFKA_JMX_PORT=39999 \
  -e KAFKA_LOG4J_LOGGERS="kafka.controller=WARN,kafka.foo.bar=DEBUG" \
  -e KAFKA_LOG4J_ROOT_LOGLEVEL=WARN \
  -e KAFKA_TOOLS_LOG4J_LOGLEVEL=ERROR \
  -e KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR=1 \
  confluentinc/cp-kafka:4.0.0

Component Names

Component	Name
ZooKeeper	KAFKA
Kafka	KAFKA
Confluent Control Center	CONTROL_CENTER
Schema Registry	SCHEMA_REGISTRY
REST Proxy	KAFKA_REST
Kafka Connect	CONNECT