How to change a Kafka configuration

1. Change the configuration on every file server.properties

2. Proceed to a rolling restart of all the brokers

#!/bin/bash

# let's apply a new setting to our server.properties
pwd
# make sure you're in the /home/ubuntu/kafka directory
cat config/server.properties
echo "unclean.leader.election.enable=false" >> config/server.properties
cat config/server.properties

# look at the logs - what was the value before?
cat logs/server.log | grep unclean.leader
# stop the broker
sudo service kafka stop
# restart the broker
sudo service kafka start
# look at the logs - what is the value after?
cat logs/server.log | grep unclean.leader

# operate on the three brokers