Kanal is configured through application.yml. This page covers all available configuration options.
Configuration File Precedence Kanal loads configuration from these locations (in this order):
Configuration files loaded in order from the system property micronaut.config.files or the environment variable MICRONAUT_CONFIG_FILES.
Environment Variables
Java System Properties
Stick to one configuration source to avoid precedence confusion.
JAR File
docker compose (with environment variables)
docker compose (with volume mount)
# With Java System Property java -jar kanal.jar -Dmicronaut.config.files=/path/to/application.yml # With Environment Variable export MICRONAUT_CONFIG_FILES = / path / to / application . yml java -jar kanal.jar
Environment Variables You can override any configuration using environment variables.
Variable naming convention:
Replace . with _
Replace - with _
Use uppercase
services : kanal : image : kanal:latest ports : - "8080:8080" environment : KAFKA_BOOTSTRAP_SERVERS : broker1:9092,broker2:9092 DATABASES_DEFAULT_CONNECTION_URL : jdbc:postgresql://pg-xxyyzz-streemlined-nnnn.c.aivencloud.com:13645/defaultdb?ssl=require DATABASES_DEFAULT_CONNECTION_USER : avnadmin DATABASES_DEFAULT_CONNECTION_PASSWORD : password PLUGIN_PATH : /libs volumes : - ./libs:/libs
Kafka Configuration Configure your Kafka connection under the kafka key:
application.yml
Environment Variables
kafka : bootstrap.servers : localhost:9092 # Authentication (optional) security.protocol : SASL_PLAINTEXT sasl.mechanism : PLAIN sasl.jaas.config : > org.apache.kafka.common.security.plain.PlainLoginModule required username="admin" password="secret"; # Consumer settings group.id : kanal-pipeline-1 auto.offset.reset : earliest max.poll.records : 5000 enable.auto.commit : false # Producer settings acks : all
Common Kafka Properties Property Default Description bootstrap.servers— Kafka broker addresses (required) group.id— Consumer group ID (required) auto.offset.resetearliestWhere to start when no offset exists max.poll.records500Max records per poll enable.auto.commitfalseAuto-commit offsets (recommended: false) acksallProducer acknowledgment level
Security Configuration application.yml
Environment Variables
kafka : bootstrap.servers : localhost:9092
application.yml
Environment Variables
kafka : bootstrap.servers : broker:9092 security.protocol : SASL_PLAINTEXT sasl.mechanism : PLAIN sasl.jaas.config : > org.apache.kafka.common.security.plain.PlainLoginModule required username="user" password="pass";
application.yml
Environment Variables
kafka : bootstrap.servers : broker:9093 security.protocol : SSL ssl.truststore.location : /path/to/truststore.jks ssl.truststore.password : truststore-pass ssl.keystore.location : /path/to/keystore.jks ssl.keystore.password : keystore-pass
Schema Registry Configure Schema Registry for Avro or Protobuf schemas:
application.yml
Environment Variables
value.converter : schema.registry.url : http://localhost:8081 # Authentication (if required) basic.auth.credentials.source : USER_INFO basic.auth.user.info : username:password
Additional Schema Registry configuration options are available, such as SSL settings, and schema caching. See the Confluent Schema Registry documentation for a complete list of configuration properties. Database Connections Configure named database connections under the databases key:
application.yml
Environment Variables
databases : default : connection.url : jdbc:postgresql://localhost:5432/mydb connection.user : postgres connection.password : secret analytics : connection.url : jdbc:postgresql://analytics-host:5432/analytics connection.user : analytics_user connection.password : analytics_pass
Reference these connections by name in your JDBC Sink nodes.
Supported Databases Kanal packages the Aiven JDBC Connector for Apache Kafka by default. Tested databases include:
PostgreSQL
MySQL / MariaDB
SQL Server
Oracle
Snowflake
SQLite
Metrics and Monitoring Kanal exposes Prometheus metrics by default:
application.yml
Environment Variables
micronaut : metrics : export : prometheus : enabled : true step : PT1M descriptions : true
Need a different metrics reporter? Micronaut Micrometer supports many alternatives including Datadog , CloudWatch , Graphite , InfluxDB , StatsD , New Relic , Dynatrace , Wavefront , Azure Monitor , Stackdriver , and more. Contact support to request an additional registry. See the Micronaut Micrometer documentation for the full list of available registries. Available Endpoints Endpoint Description /healthHealth check status /prometheusPrometheus metrics /metricsMicrometer endpoint for humans and debugging, not for tooling or long-term integration.
Logging Configure logging levels via application properties:
application.yml
Environment Variables
logger : levels : io.kanal : INFO org.apache.kafka : WARN
Log Levels Level Use Case TRACEOnly if requested by Support DEBUGDevelopment and troubleshooting INFONormal operation WARNProduction (recommended) ERRORMinimal logging
Next Steps 
