After installing Aiven command-line client, you can use
avn service types -v to see all available options and allowed values.
For example, to set
message.max.bytes , you can use
avn service update myservice -c "kafka.message_max_bytes=newmaximumbytelimit" .
Do note changing most of the Kafka settings will cause Kafka service to restart. Aiven Kafka restarts nodes one at the time, causing minimal disruption to the service availability. However, due to this, after altering Kafka settings, it will take a few minutes before new settings are in use.
message.max.bytes , remember to change your client settings as well - otherwise you may have issues with processing Kafka messages.