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Set up TLS encryption and authentication for Non-ESP Apache Kafka cluster in Azure HDInsight

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This article shows you how to set up Transport Layer Security (TLS) encryption, previously known as Secure Sockets Layer (SSL) encryption, between Apache Kafka clients and Apache Kafka brokers. It also shows you how to set up authentication of clients (sometimes referred to as two-way TLS).

Important

There are two clients which you can use for Kafka applications: a Java client and a console client. Only the Java client ProducerConsumer.java can use TLS for both producing and consuming. The console producer client console-producer.sh does not work with TLS.

Apache Kafka broker setup

The Kafka TLS broker setup uses four HDInsight cluster VMs in the following way:

  • headnode 0 - Certificate Authority (CA)
  • worker node 0, 1, and 2 - brokers

Note

This guide uses self-signed certificates, but the most secure solution is to use certificates issued by trusted CAs.

The summary of the broker setup process is as follows:

  1. The following steps are repeated on each of the three worker nodes:

    1. Generate a certificate.
    2. Create a cert signing request.
    3. Send the cert signing request to the Certificate Authority (CA).
    4. Sign in to the CA and sign the request.
    5. SCP the signed certificate back to the worker node.
    6. SCP the public certificate of the CA to the worker node.

  2. Once you have all of the certificates, put the certs into the cert store.

  3. Go to Ambari and change the configurations.

    Use the following detailed instructions to complete the broker setup:

    Important

    In the following code snippets wnX is an abbreviation for one of the three worker nodes and should be substituted with wn0, wn1 or wn2 as appropriate. WorkerNode0_Name and HeadNode0_Name should be substituted with the names of the respective machines.

  4. Perform initial setup on head node 0, which for HDInsight fills the role of the Certificate Authority (CA).

    # Create a new directory 'ssl' and change into it
mkdir ssl
cd ssl

  5. Perform the same initial setup on each of the brokers (worker nodes 0, 1 and 2).

    # Create a new directory 'ssl' and change into it
mkdir ssl
cd ssl

  6. On each of the worker nodes, execute the following steps using the code snippet.

    1. Create a keystore and populate it with a new private certificate.
    2. Create a certificate signing request.
    3. SCP the certificate signing request to the CA (headnode0)
    keytool -genkey -keystore kafka.server.keystore.jks -keyalg RSA -validity 365 -storepass "MyServerPassword123" -keypass "MyServerPassword123" -dname "CN=FQDN_WORKER_NODE" -ext SAN=DNS:FQDN_WORKER_NODE -storetype pkcs12
keytool -keystore kafka.server.keystore.jks -certreq -file cert-file -storepass "MyServerPassword123" -keypass "MyServerPassword123"
scp cert-file sshuser@HeadNode0_Name:~/ssl/wnX-cert-sign-request

    Note

    FQDN_WORKER_NODE is Fully Qualified Domain Name of worker node machine.You can get that details from /etc/hosts file in head node

    For example,

    wn0-espkaf.securehadooprc.onmicrosoft.com
wn0-kafka2.zbxwnwsmpcsuvbjqbmespcm1zg.bx.internal.cloudapp.net

    Screenshot showing hosts file output.

  7. On the CA machine, run the following command to create ca-cert and ca-key files:

    openssl req -new -newkey rsa:4096 -days 365 -x509 -subj "/CN=Kafka-Security-CA" -keyout ca-key -out ca-cert -nodes

  8. Change to the CA machine and sign all of the received cert signing requests:

    openssl x509 -req -CA ca-cert -CAkey ca-key -in wn0-cert-sign-request -out wn0-cert-signed -days 365 -CAcreateserial -passin pass:"MyServerPassword123"
openssl x509 -req -CA ca-cert -CAkey ca-key -in wn1-cert-sign-request -out wn1-cert-signed -days 365 -CAcreateserial -passin pass:"MyServerPassword123"
openssl x509 -req -CA ca-cert -CAkey ca-key -in wn2-cert-sign-request -out wn2-cert-signed -days 365 -CAcreateserial -passin pass:"MyServerPassword123"

  9. Send the signed certificates back to the worker nodes from the CA (headnode0).

    scp wn0-cert-signed sshuser@WorkerNode0_Name:~/ssl/cert-signed
scp wn1-cert-signed sshuser@WorkerNode1_Name:~/ssl/cert-signed
scp wn2-cert-signed sshuser@WorkerNode2_Name:~/ssl/cert-signed

  10. Send the public certificate of the CA to each worker node.

    scp ca-cert sshuser@WorkerNode0_Name:~/ssl/ca-cert
scp ca-cert sshuser@WorkerNode1_Name:~/ssl/ca-cert
scp ca-cert sshuser@WorkerNode2_Name:~/ssl/ca-cert

  11. On each worker node, add the CAs public certificate to the truststore and keystore. Then add the worker node's own signed certificate to the keystore

    keytool -keystore kafka.server.truststore.jks -alias CARoot -import -file ca-cert -storepass "MyServerPassword123" -keypass "MyServerPassword123" -noprompt
keytool -keystore kafka.server.keystore.jks -alias CARoot -import -file ca-cert -storepass "MyServerPassword123" -keypass "MyServerPassword123" -noprompt
keytool -keystore kafka.server.keystore.jks -import -file cert-signed -storepass "MyServerPassword123" -keypass "MyServerPassword123" -noprompt

Update Kafka configuration to use TLS and restart brokers

You have now set up each Kafka broker with a keystore and truststore, and imported the correct certificates. Next, modify related Kafka configuration properties using Ambari and then restart the Kafka brokers.

To complete the configuration modification, do the following steps:

  1. Sign in to the Azure portal and select your Azure HDInsight Apache Kafka cluster.

  2. Go to the Ambari UI by clicking Ambari home under Cluster dashboards.

  3. Under Kafka Broker set the listeners property to PLAINTEXT://localhost:9092,SSL://localhost:9093

  4. Under Advanced kafka-broker set the security.inter.broker.protocol property to SSL

    Editing Kafka ssl configuration properties in Ambari.

  5. Under Custom kafka-broker set the ssl.client.auth property to required.

    Note

    Note: This step is only required if you're setting up authentication and encryption.

    Editing kafka ssl configuration properties in Ambari.

  6. Here's the screenshot that shows Ambari configuration UI with these changes.

    Note

    1. ssl.keystore.location and ssl.truststore.location is the complete path of your keystore, truststore location in Certificate Authority (hn0)
    2. ssl.keystore.password and ssl.truststore.password is the password set for the keystore and truststore. In this case as an example, MyServerPassword123
    3. ssl.key.password is the key set for the keystore and trust store. In this case as an example, MyServerPassword123

  7. To Use TLS 1.3 in Kafka

    Add following configs to the kafka configs in Ambari

    1. ssl.enabled.protocols=TLSv1.3
    2. ssl.protocol=TLSv1.3

    Important

    1. TLS 1.3 works with HDI 5.1 kafka version only.
    2. If you use TLS 1.3 at server side, you should use TLS 1.3 configs at client too.

  8. For HDI version 4.0 or 5.0

    1. If you're setting up authentication and encryption, then the screenshot looks like

    Editing kafka-env template property in Ambari four.

    1. If you're setting up encryption only, then the screenshot looks like

    Screenshot showing how to edit kafka-env template property field in Ambari for encryption only.

  9. Restart all Kafka brokers.

Client setup (without authentication)

If you don't need authentication, the summary of the steps to set up only TLS encryption are:

  1. Sign in to the CA (active head node).
  2. Copy the CA certificate to client machine from the CA machine (wn0).
  3. Sign in to the client machine (hn1) and navigate to the ~/ssl folder.
  4. Import the CA certificate to the truststore.
  5. Import the CA certificate to the keystore.

These steps are detailed in the following code snippets.

  1. Sign in to the CA node.

    ssh sshuser@HeadNode0_Name
cd ssl

  2. Copy the ca-cert to the client machine

    scp ca-cert sshuser@HeadNode1_Name:~/ssl/ca-cert

  3. Sign in to the client machine (standby head node).

    ssh sshuser@HeadNode1_Name
cd ssl

  4. Import the CA certificate to the truststore.

    keytool -keystore kafka.client.truststore.jks -alias CARoot -import -file ca-cert -storepass "MyClientPassword123" -keypass "MyClientPassword123" -noprompt

  5. Import the CA certificate to keystore.

    keytool -keystore kafka.client.keystore.jks -alias CARoot -import -file ca-cert -storepass "MyClientPassword123" -keypass "MyClientPassword123" -noprompt

  6. Create the file client-ssl-auth.properties on client machine (hn1). It should have the following lines:

    security.protocol=SSL
ssl.truststore.location=/home/sshuser/ssl/kafka.client.truststore.jks
ssl.truststore.password=MyClientPassword123
    1. To Use TLS 1.3 add following configs to file client-ssl-auth.properties
    ssl.enabled.protocols=TLSv1.3
ssl.protocol=TLSv1.3

  7. Start the admin client with producer and consumer options to verify that both producers and consumers are working on port 9093. Refer to Verification section for steps needed to verify the setup using console producer/consumer.

Client setup (with authentication)

Note

The following steps are required only if you are setting up both TLS encryption and authentication. If you are only setting up encryption, then see Client setup without authentication.

The following four steps summarize the tasks needed to complete the client setup:

  1. Sign in to the client machine (standby head node).
  2. Create a Java keystore and get a signed certificate for the broker. Then copy the certificate to the VM where the CA is running.
  3. Switch to the CA machine (active head node) to sign the client certificate.
  4. Go to the client machine (standby head node) and navigate to the ~/ssl folder. Copy the signed cert to client machine.

The details of each step are given.

  1. Sign in to the client machine (standby head node).

    ssh sshuser@HeadNode1_Name

  2. Remove any existing ssl directory.

    rm -R ~/ssl
mkdir ssl
cd ssl

  3. Create a Java keystore and create a certificate signing request.

    keytool -genkey -keystore kafka.client.keystore.jks -validity 365 -storepass "MyClientPassword123" -keypass "MyClientPassword123" -dname "CN=HEADNODE1_FQDN" -storetype pkcs12

keytool -keystore kafka.client.keystore.jks -certreq -file client-cert-sign-request -storepass "MyClientPassword123" -keypass "MyClientPassword123"

  4. Copy the certificate signing request to the CA

    scp client-cert-sign-request sshuser@HeadNode0_Name:~/ssl/client-cert-sign-request

  5. Switch to the CA machine (active head node) and sign the client certificate.

    ssh sshuser@HeadNode0_Name
cd ssl
openssl x509 -req -CA ca-cert -CAkey ca-key -in ~/ssl/client-cert-sign-request -out ~/ssl/client-cert-signed -days 365 -CAcreateserial -passin pass:MyClientPassword123

  6. Copy signed client cert from the CA (active head node) to client machine.

    scp client-cert-signed sshuser@HeadNode1_Name:~/ssl/client-signed-cert

  7. Copy the ca-cert to the client machine

    scp ca-cert sshuser@HeadNode1_Name:~/ssl/ca-cert
    1. Sign in to the client machine (standby head node) and navigate to ssl directory.
    ssh sshuser@HeadNode1_Name
cd ssl

  8. Create client store with signed cert, import CA cert into the keystore, and truststore on client machine (hn1):

    keytool -keystore kafka.client.truststore.jks -alias CARoot -import -file ca-cert -storepass "MyClientPassword123" -keypass "MyClientPassword123" -noprompt

keytool -keystore kafka.client.keystore.jks -alias CARoot -import -file ca-cert -storepass "MyClientPassword123" -keypass "MyClientPassword123" -noprompt

keytool -keystore kafka.client.keystore.jks -import -file client-signed-cert -storepass "MyClientPassword123" -keypass "MyClientPassword123" -noprompt

  9. Create a file client-ssl-auth.properties on client machine (hn1). It should have the following lines:

    security.protocol=SSL
ssl.truststore.location=/home/sshuser/ssl/kafka.client.truststore.jks
ssl.truststore.password=MyClientPassword123
ssl.keystore.location=/home/sshuser/ssl/kafka.client.keystore.jks
ssl.keystore.password=MyClientPassword123
ssl.key.password=MyClientPassword123
    1. To Use TLS 1.3 add following configs to file client-ssl-auth.properties
    ssl.enabled.protocols=TLSv1.3
ssl.protocol=TLSv1.3

Verification

Run these steps on the client machine.

Note

If HDInsight 4.0 and Kafka 2.1 is installed, you can use the console producer/consumers to verify your setup. If not, run the Kafka producer on port 9092 and send messages to the topic, and then use the Kafka consumer on port 9093 which uses TLS.

Kafka 2.1 or above

  1. Create a topic if it doesn't exist already.

    /usr/hdp/current/kafka-broker/bin/kafka-topics.sh --zookeeper <ZOOKEEPER_NODE>:2181 --create --topic topic1 --partitions 2 --replication-factor 2

  2. Start console producer and provide the path to client-ssl-auth.properties as a configuration file for the producer.

    /usr/hdp/current/kafka-broker/bin/kafka-console-producer.sh --broker-list <FQDN_WORKER_NODE>:9093 --topic topic1 --producer.config ~/ssl/client-ssl-auth.properties

  3. Open another ssh connection to client machine and start console consumer and provide the path to client-ssl-auth.properties as a configuration file for the consumer.

    /usr/hdp/current/kafka-broker/bin/kafka-console-consumer.sh --bootstrap-server <FQDN_WORKER_NODE>:9093 --topic topic1 --consumer.config ~/ssl/client-ssl-auth.properties --from-beginning

Next steps