If you want to expose your Kafka brokers so that external clients can communicate with them, it is important to make sure that your implementation is secure. In some situations, this means implementing client authentication. In this lab, you will have the opportunity to work hands-on with one of the client authentication methods available in Kafka: client certificates. You will implement authentication with client certificates in an existing cluster, and then authenticate as a client to verify that your implementation works. This will give you hands-on experience with the process of securing a Kafka cluster.
Learning Objectives
Successfully complete this lab by achieving the following learning objectives:
- Generate Your Client Certificate Files
Generate a client certificate. Choose a password for the client keystore when prompted:
cd ~/certs/ keytool -keystore client.keystore.jks -alias kafkauser -validity 365 -genkey -keyalg RSA -dname "CN=kafkauser, OU=Unknown, O=Unknown, L=Unknown, ST=Unknown, C=Unknown"Sign the key, then import the certificate authority and signed key into the
keystore. When asked for the password to theca-key, enter the passwordAllTheKeys:keytool -keystore client.keystore.jks -alias kafkauser -certreq -file client-cert-file openssl x509 -req -CA ca-cert -CAkey ca-key -in client-cert-file -out client-cert-signed -days 365 -CAcreateserial keytool -keystore client.keystore.jks -alias CARoot -import -file ca-cert keytool -keystore client.keystore.jks -alias kafkauser -import -file client-cert-signedMove the client keystore into an appropriate location:
sudo cp client.keystore.jks /var/private/ssl/ sudo chown root:root /var/private/ssl/client.keystore.jks
- Enable Client Authentication for the Broker
Set client authentication to
requiredinserver.properties:sudo vi /etc/kafka/server.propertiesLocate the line that begins with
ssl.client.authand change it:ssl.client.auth=requiredRestart Kafka and then verify that everything is working:
sudo systemctl restart confluent-kafka sudo systemctl status confluent-kafka
- Add Client Authentication Settings to Your Client Config File
Edit
client-ssl.properties:cd ~/ vi client-ssl.propertiesAdd the following lines:
ssl.keystore.location=/var/private/ssl/client.keystore.jks ssl.keystore.password=<your client keystore password> ssl.key.password=<your client key password>Create a console consumer using client authentication to make verify that everything is working:
kafka-console-consumer --bootstrap-server zoo1:9093 --topic inventory_purchases --from-beginning --consumer.config client-ssl.properties
