KAFKA_OPTS and KAFKA_HEAP_OPTS causing java starting errors

[GuardMoony]

Name and Version

bitnami/kafka

What architecture are you using?

None

What steps will reproduce the bug?

1. Create a docker compose file with KAFKA_OPTS or KAFKA_HEAP_OPTS set.

example docker-compose.yml:

services:

  kafka:
    container_name: kafka
    image: bitnami/kafka
    volumes:
      - "./kafka-persistence:/bitnami/kafka"
    environment:
      - KAFKA_CFG_NODE_ID=0
      - KAFKA_CFG_PROCESS_ROLES=controller,broker
      - KAFKA_CFG_LISTENERS=PLAINTEXT://:9092,CONTROLLER://:9093
      - KAFKA_CFG_LISTENER_SECURITY_PROTOCOL_MAP=CONTROLLER:PLAINTEXT,PLAINTEXT:PLAINTEXT
      - KAFKA_CFG_CONTROLLER_QUORUM_VOTERS=0@kafka:9093
      - KAFKA_CFG_CONTROLLER_LISTENER_NAMES=CONTROLLER
      - KAFKA_CFG_AUTO_CREATE_TOPICS_ENABLE=true
      - KAFKA_HEAP_OPTS='-Xmx1024m -Xms1024m'
     - KAFKA_OPTS='-javaagent:/bitnami/kafka/agents/jmx_prometheus_javaagent-1.0.1.jar=7071:/bitnami/kafka/agents/config.yml'
    expose:
      - "7071"
      - "9092"
      - "9093"
    restart: unless-stopped

2. In case of my example:
   • Create the persistence directory.
   • Create agents directory inside the persistence directory.
   • Download the JMX exporter
   • Add a simple config.yml

     rules:
       - pattern: ".*"
     

What is the expected behavior?

For KAFKA_HEAP_OPTS: Expecting to set set heap variables for java. This is mainly to limit memory usage and garbage collection settings.

For KAFKA_OPTS: Expecting to add extra java launch parameters.

What do you see instead?

Logs:

$ docker compose up
[+] Running 1/0
 ✔ Container kafka  Created                                                                                                                                                                                               0.0s 
Attaching to kafka
kafka  | kafka 09:26:22.15 INFO  ==> 
kafka  | kafka 09:26:22.15 INFO  ==> Welcome to the Bitnami kafka container
kafka  | kafka 09:26:22.15 INFO  ==> Subscribe to project updates by watching https://github.com/bitnami/containers
kafka  | kafka 09:26:22.15 INFO  ==> Submit issues and feature requests at https://github.com/bitnami/containers/issues
kafka  | kafka 09:26:22.15 INFO  ==> Upgrade to Tanzu Application Catalog for production environments to access custom-configured and pre-packaged software components. Gain enhanced features, including Software Bill of Materials (SBOM), CVE scan result reports, and VEX documents. To learn more, visit https://bitnami.com/enterprise
kafka  | kafka 09:26:22.15 INFO  ==> 
kafka  | kafka 09:26:22.16 INFO  ==> ** Starting Kafka setup **
kafka  | kafka 09:26:22.21 WARN  ==> Kafka has been configured with a PLAINTEXT listener, this setting is not recommended for production environments.
kafka  | kafka 09:26:22.22 INFO  ==> Initializing Kafka...
kafka  | kafka 09:26:22.23 INFO  ==> No injected configuration files found, creating default config files
kafka  | kafka 09:26:22.35 INFO  ==> Initializing KRaft storage metadata
kafka  | kafka 09:26:22.35 INFO  ==> Formatting storage directories to add metadata...
kafka  | Error: Could not find or load main class '-Xmx1024m
kafka  | Caused by: java.lang.ClassNotFoundException: '-Xmx1024m
kafka exited with code 0

$ docker compose up
[+] Running 1/0
 ✔ Container kafka  Recreated                                                                                                                                                                                             0.1s 
Attaching to kafka
kafka  | kafka 09:33:29.54 INFO  ==> 
kafka  | kafka 09:33:29.54 INFO  ==> Welcome to the Bitnami kafka container
kafka  | kafka 09:33:29.54 INFO  ==> Subscribe to project updates by watching https://github.com/bitnami/containers
kafka  | kafka 09:33:29.54 INFO  ==> Submit issues and feature requests at https://github.com/bitnami/containers/issues
kafka  | kafka 09:33:29.54 INFO  ==> Upgrade to Tanzu Application Catalog for production environments to access custom-configured and pre-packaged software components. Gain enhanced features, including Software Bill of Materials (SBOM), CVE scan result reports, and VEX documents. To learn more, visit https://bitnami.com/enterprise
kafka  | kafka 09:33:29.55 INFO  ==> 
kafka  | kafka 09:33:29.55 INFO  ==> ** Starting Kafka setup **
kafka  | kafka 09:33:29.61 WARN  ==> Kafka has been configured with a PLAINTEXT listener, this setting is not recommended for production environments.
kafka  | kafka 09:33:29.62 INFO  ==> Initializing Kafka...
kafka  | kafka 09:33:29.62 INFO  ==> No injected configuration files found, creating default config files
kafka  | kafka 09:33:29.74 INFO  ==> Initializing KRaft storage metadata
kafka  | kafka 09:33:29.75 INFO  ==> Formatting storage directories to add metadata...
kafka  | Error: Could not find or load main class '-javaagent:.bitnami.kafka.agents.jmx_prometheus_javaagent-1.0.1.jar=7071:.bitnami.kafka.agents.config.yml'
kafka  | Caused by: java.lang.ClassNotFoundException: '-javaagent:.bitnami.kafka.agents.jmx_prometheus_javaagent-1.0.1.jar=7071:.bitnami.kafka.agents.config.yml'
kafka exited with code 0

Additional information

Came across this bug when i wanted to add the jmx exporter inside the container for prometheus metrics.