Kafka

Enabling encryption for Apache Kafka clients

Kafka allows you to distribute the load between nodes receiving data and encrypts communication.

Architecture example:

The Kafka installation

Documentation during creation.

Enabling encryption in Kafka

Generate SSL key and certificate for each Kafka broker

keytool -keystore server.keystore.jks -alias localhost -validity {validity} -genkey -keyalg RSA

Configuring Host Name In Certificates

keytool -keystore server.keystore.jks -alias localhost -validity {validity} -genkey -keyalg RSA -ext SAN=DNS:{FQDN}

Verify content of the generated certificate:

keytool -list -v -keystore server.keystore.jks

Creating your own CA

openssl req -new -x509 -keyout ca-key -out ca-cert -days 365
keytool -keystore client.truststore.jks -alias CARoot -import -file ca-cert
keytool -keystore server.truststore.jks -alias CARoot -import -file ca-cert

Signing the certificate

keytool -keystore server.keystore.jks -alias localhost -certreq -file cert-file
openssl x509 -req -CA ca-cert -CAkey ca-key -in cert-file -out cert-signed -days {validity} -CAcreateserial -passin pass:{ca-password}

Import both the certificate of the CA and the signed certificate into the keystore

keytool -keystore server.keystore.jks -alias CARoot -import -file ca-cert
keytool -keystore server.keystore.jks -alias localhost -import -file cert-signed

If you have trusted certificates, you must import them into the JKS keystore as follows:

Create a keystore:

keytool -keystore client.keystore.jks -alias localhost -validity 365 -keyalg RSA -genkey

Combine the certificate and key file into a certificate in p12 format:

openssl pkcs12 -export -in cert_name.crt -inkey key_name.key -out cert_name.p12 -name localhost -CAfile ca.crt -caname root

Import the CA certificate into a truststore:

keytool -keystore client.truststore.jks -alias CARoot -import -file ca-cert

Import the CA certificate into a keystore:

keytool -keystore client.keystore.jks -alias CARoot -import -file ca-cert

Import the p12 certificate into a keystore:

keytool -importkeystore -deststorepass MY-KEYSTORE-PASS -destkeystore client.keystore.jks -srckeystore cert_name.p12 -srcstoretype PKCS12

Configuring Kafka Brokers

In /etc/kafka/server.properties file set the following options:

listeners=PLAINTEXT://host.name:port,SSL://host.name:port

ssl.keystore.location=/var/private/ssl/server.keystore.jks
ssl.keystore.password=test1234
ssl.key.password=test1234
ssl.truststore.location=/var/private/ssl/server.truststore.jks
ssl.truststore.password=test1234

and restart the Kafka service

systemctl restart kafka

Configuring Kafka Clients

Logstash

Configure the output section in Logstash based on the following example:

output {
  kafka {
    bootstrap_servers => "host.name:port"
    security_protocol => "SSL"
    ssl_truststore_type => "JKS"
    ssl_truststore_location => "/var/private/ssl/client.truststore.jks"
    ssl_truststore_password => "test1234"
    client_id => "host.name"
    topic_id => "Topic-1"
    codec => json
  }
}

Configure the input section in Logstash based on the following example:

input {
  kafka {
    bootstrap_servers => "host.name:port"
    security_protocol => "SSL"
    ssl_truststore_type => "JKS"
    ssl_truststore_location => "/var/private/ssl/client.truststore.jks"
    ssl_truststore_password => "test1234"
    consumer_threads => 4
    topics => [ "Topic-1" ]
    codec => json
    tags => ["kafka"]
   }
}

Log retention for Kafka topic

The Kafka durably persists all published records—whether or not they have been consumed—using a configurable retention period. For example, if the retention policy is set to two days, then for the two days after a record is published, it is available for consumption, after which it will be discarded to free up space. Kafka’s performance is effectively constant with respect to data size so storing data for a long time is not a problem.