Configuring TLS Encryption for Cloudera Manager

When you configure authentication and authorization on a cluster, Cloudera Manager Server sends sensitive information over the network to cluster hosts, such as Kerberos keytabs and configuration files that contain passwords. To secure this transfer, you must configure TLS encryption between Cloudera Manager Server and all cluster hosts.

TLS encryption is also used to secure client connections to the Cloudera Manager Admin Interface, using HTTPS.

Cloudera Manager also supports TLS authentication. Without certificate authentication, a malicious user can add a host to Cloudera Manager by installing the Cloudera Manager Agent software and configuring it to communicate with Cloudera Manager Server. To prevent this, you must install certificates on each agent host and configure Cloudera Manager Server to trust those certificates.

This guide shows how to configure and enable TLS encryption and certificate authentication for Cloudera Manager. The provided examples use an internal certificate authority (CA) to sign all TLS certificates, so this guide also shows you how to establish trust with the CA. (For certificates signed by a trusted public CA, establishing trust is not necessary, because the Java Development Kit (JDK) already trusts them.)

Use this guide to enable TLS encryption and certificate authentication for Cloudera Manager:

  1. Generate TLS Certificates
  2. Configure TLS for the Cloudera Manager Admin Console
  3. Configure TLS for Cloudera Manager Agents
  4. Enable Server Certificate Verification on Cloudera Manager Agents
  5. Configure Agent Certificate Authentication

Generate TLS Certificates

The following procedure assumes that an internal certificate authority (CA) is used, and shows how to establish trust for that internal CA. If you are using a trusted public CA (such as Symantec, GeoTrust, Comodo, and others), you do not need to explicitly establish trust for the issued certificates, unless you are using an older JDK and a newer public CA. Older JDKs might not trust newer public CAs by default.

On Each Cluster Host:

Complete the following procedure on each cluster host, including the Cloudera Manager Server host.

  1. Configure your environment to set JAVA_HOME to the Oracle JDK. For example: 
    export JAVA_HOME=/usr/java/jdk1.8.0_162
    If you log out of the host before completing this procedure, make sure to set JAVA_HOME again when you log in to complete the steps.
  2. Create the /opt/cloudera/security/pki directory: 
    sudo mkdir -p /opt/cloudera/security/pki
    If you choose to use a different directory, make sure you use the same directory on all cluster hosts to simplify management and maintenance.
  3. Use the keytool utility to generate a Java keystore and certificate signing request (CSR). Replace the OU, O, L, ST, and C entries with the values for your environment. When prompted, use the same password for the keystore password and key password. Cloudera Manager does not support using different passwords for the key and keystore. 
    $JAVA_HOME/bin/keytool -genkeypair -alias $(hostname -f) -keyalg RSA -keystore /opt/cloudera/security/pki/$(hostname -f).jks -keysize 2048 -dname "CN=$(hostname -f),OU=Engineering,O=Cloudera,L=Palo Alto,ST=California,C=US" -ext san=dns:$(hostname -f)
    $JAVA_HOME/bin/keytool -certreq -alias $(hostname -f) -keystore /opt/cloudera/security/pki/$(hostname -f).jks -file /opt/cloudera/security/pki/$(hostname -f).csr -ext san=dns:$(hostname -f) -ext EKU=serverAuth,clientAuth
  4. Submit the CSR files (for example, cm01.example.com.csr) to your certificate authority to obtain a server certificate.

    For security purposes, many commercial CAs ignore requested extensions in a CSR. Make sure that you inform the CA that you require certificates with both server and client authentication options.

    If possible, obtain the certificate in PEM (Base64 ASCII) format. The certificate file is in PEM format if it looks similar to this (some lines omitted): 
    -----BEGIN CERTIFICATE-----
MIIDAzCCAesCAQAwgY0xCzAJBgNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlh
MRIwEAYDVQQHEwlQYWxvIEFsdG8xETAPBgNVBAoTCENsb3VkZXJhMRQwEgYDVQQL
…
tudY0C32LjGjWOg5ALliN9Oy1u2xRKGAVfapbzAZ2rchtlCZc7mtaT6BXgW8S+Db
0HhuObn1/8TL4Ho9G+KlJB3MWik2oEbOvQt0rBidMr9qaNX86m0i7pouXZelZ5c5
UnDPtrhW6A==
-----END CERTIFICATE-----

    If your issued certificate is in binary (DER) format, convert it to PEM format.

  5. After you have received the signed certificate, copy the signed certificate to the following location: 
    /opt/cloudera/security/pki/$(hostname -f).pem
  6. Inspect the signed certificate to verify that both server and client authentication options are present, as well as the subject alternative name: 
    openssl x509 -in /opt/cloudera/security/pki/$(hostname -f).pem -noout -text

    Look for output similar to the following to verify the server and client authentication options:

                X509v3 Extended Key Usage:
                TLS Web Server Authentication, TLS Web Client Authentication

    Look for output similar to the following to validate the subject alternative name:

                X509v3 Subject Alternative Name:
                DNS:hostname.example.com
  7. Copy the root and intermediate CA certificates to /opt/cloudera/security/pki/rootca.pem and /opt/cloudera/security/pki/intca.pem on each host. If you have a concatenated file containing the root CA and an intermediate CA certificate, split the file along the END CERTIFICATE/BEGIN CERTIFICATE boundary into individual files. If there are multiple intermediate CA certificates, use unique file names such as intca-1.pem, intca-2.pem, and so on.
  8. Copy the JDK cacerts file to jssecacerts as follows: 
    sudo cp $JAVA_HOME/jre/lib/security/cacerts $JAVA_HOME/jre/lib/security/jssecacerts

    The Oracle JDK uses the jssecacerts file for its default truststore if it exists. Otherwise, it uses the cacerts file. Creating the jssecacerts file allows you to trust an internal CA without modifying the cacerts file that is included with the JDK.

  9. Import the root CA certificate into the JDK truststore. 
    sudo $JAVA_HOME/bin/keytool -importcert -alias rootca -keystore $JAVA_HOME/jre/lib/security/jssecacerts -file /opt/cloudera/security/pki/rootca.pem

    If you see a message like the following, enter yes to continue:

    Trust this certificate? [no]: yes
    You must see the following response verifying that the certificate has been properly imported: 
    Certificate was added to keystore
  10. Append the intermediate CA certificate to the signed host certificate, and then import it into the keystore. Make sure that you use the append operator (>>) and not the overwrite operator (>): 
    sudo cat /opt/cloudera/security/pki/intca.pem >> /opt/cloudera/security/pki/$(hostname -f).pem
    sudo $JAVA_HOME/bin/keytool -importcert -alias $(hostname -f) -file /opt/cloudera/security/pki/$(hostname -f).pem -keystore /opt/cloudera/security/pki/$(hostname -f).jks

    If you see a message like the following, enter yes to continue:

    ... is not trusted. Install reply anyway? [no]:  yes
    You must see the following response verifying that the certificate has been properly imported: 
    Certificate reply was installed in keystore

    If you do not see this response, contact Cloudera Support.

  11. Create symbolic links (symlink) for the certificate and keystore files: 
    sudo ln -s /opt/cloudera/security/pki/$(hostname -f).pem /opt/cloudera/security/pki/agent.pem

    This allows you to use the same /etc/cloudera-scm-agent/config.ini file on all agent hosts rather than maintaining a file for each agent.

On the Cloudera Manager Server Host

On the Cloudera Manager Server host, create an additional symlink for the keystore file: 
sudo ln -s /opt/cloudera/security/pki/$(hostname -f).jks /opt/cloudera/security/pki/server.jks

Configure TLS for the Cloudera Manager Admin Console

Minimum Required Role: Cluster Administrator (also provided by Full Administrator)

Use the following procedure to enable TLS encryption for the Cloudera Manager Server admin interface. Make sure you have generated the host certificate as described in Generate TLS Certificates.

Step 1: Enable HTTPS for the Cloudera Manager Admin Console

  1. Log in to the Cloudera Manager Admin Console.
  2. Select Administration > Settings.
  3. Select the Security category.
  4. Configure the following TLS settings:
    Property Description
    Cloudera Manager TLS/SSL Server JKS Keystore File Location The complete path to the keystore file. For example: 
    /opt/cloudera/security/pki/server.jks
    Cloudera Manager TLS/SSL Server JKS Keystore File Password The password for the /opt/cloudera/security/jks/server.jks keystore.
    Use TLS Encryption for Admin Console Check this box to enable TLS encryption for Cloudera Manager.
  5. Enter a Reason for Change, then click Save Changes to save the settings.

Step 2: Specify SSL Truststore Properties for Cloudera Management Services

When enabling TLS for the Cloudera Manager Server admin interface, you must set the Java truststore location and password in the Cloudera Management Services configuration. Otherwise, roles such as Host Monitor and Service Monitor cannot connect to Cloudera Manager Server and will not start.

Configure the path and password for the $JAVA_HOME/jre/lib/security/jssecacerts truststore that you created earlier. Make sure that you have created this file on all hosts, including the Cloudera Management Service hosts, as instructed in Generate TLS Certificates.

  1. Open the Cloudera Manager Administration Console and go to the Cloudera Management Service service.
  2. Click the Configuration tab.
  3. Select Scope > Cloudera Management Service (Service-Wide).
  4. Select Category > Security.
  5. Edit the following TLS/SSL properties according to your cluster configuration.
    Property Description
    TLS/SSL Client Truststore File Location The path to the client truststore file used in HTTPS communication. This truststore contains certificates of trusted servers, or of Certificate Authorities trusted to identify servers. For this example, set the value to: 
    <JAVA_HOME>/jre/lib/security/jssecacerts
    Replace <JAVA_HOME> with the path to the Oracle JDK.
    Cloudera Manager Server TLS/SSL Certificate Trust Store Password The password for the truststore file.
  6. Click Save Changes to commit the changes.

Step 3: Restart Cloudera Manager and Services

You must restart both Cloudera Manager Server and the Cloudera Management Service for TLS encryption to work. Otherwise, the Cloudera Management Services (such as Host Monitor and Service Monitor) cannot communicate with Cloudera Manager Server.

  1. Restart the Cloudera Manager Server by running the following command on the Cloudera Manager Server host:
    • RHEL 7 compatible: 
      sudo systemctl restart cloudera-scm-server
    • RHEL 6 compatible, SLES, Ubuntu:
    • sudo service cloudera-scm-server restart
  2. After the restart completes, connect to the Cloudera Manager Admin Console using the HTTPS URL (for example: https://cm01.example.com:7183). If you used an internal CA-signed certificate, you must configure your browser to trust the certificate. Otherwise, you will see a warning in your browser any time you access the Cloudera Manager Administration Console. By default, certificates issued by public commercial CAs are trusted by most browsers, and no additional configuration is necessary if your certificate is signed by one of them.
  3. Restart the Cloudera Management Service (Cloudera Management Service > Actions > Restart).

Configure TLS for Cloudera Manager Agents

Minimum Required Role: Cluster Administrator (also provided by Full Administrator)

Use the following procedure to encrypt the communication between Cloudera Manager Server and Cloudera Manager Agents:

Step 1: Enable TLS Encryption for Agents in Cloudera Manager

Configure the TLS properties for Cloudera Manager Agents.

  1. Log in to the Cloudera Manager Admin Console.
  2. Select Administration > Settings.
  3. Select the Security category.
  4. Select the Use TLS Encryption for Agents option.
  5. Click Save Changes to commit the changes.

Step 2: Enable TLS on Cloudera Manager Agent Hosts

To enable TLS between the Cloudera Manager agents and Cloudera Manager, you must specify values for the TLS properties in the /etc/cloudera-scm-agent/config.ini configuration file on all agent hosts.
  1. On each agent host (including the Cloudera Manager Server host, which also has an agent), open the /etc/cloudera-scm-agent/config.ini configuration file and set the use_tls parameter in the [Security] section as follows: 
    use_tls=1

    Alternatively, you can edit the config.ini file on one host, and then copy it to the other hosts because this file by default does not contain host-specific information. If you have modified properties such as listening_hostname or listening_ip address in config.ini, you must edit the file individually on each host.

Step 3: Restart Cloudera Manager Server and Agents

  1. Restart the Cloudera Manager Server by running the following command on the Cloudera Manager Server host:
    • RHEL 7 compatible: 
      sudo systemctl restart cloudera-scm-server
    • RHEL 6 compatible, SLES, Ubuntu:
    • sudo service cloudera-scm-server restart
  2. On each agent host (including the Cloudera Manager Server host), restart the Cloudera Manager agent service:
    • RHEL 7 compatible: 
      sudo systemctl restart cloudera-scm-agent
    • RHEL 6 compatible, SLES, Ubuntu:
    • sudo service cloudera-scm-agent restart

Step 4: Verify that the Cloudera Manager Server and Agents are Communicating

In the Cloudera Manager Admin Console, go to Hosts > All Hosts. If you see successful heartbeats reported in the Last Heartbeat column after restarting the agents, TLS encryption is working properly.

Enable Server Certificate Verification on Cloudera Manager Agents

Minimum Required Role: Cluster Administrator (also provided by Full Administrator)

If you have completed the previous sections, communication between Cloudera Manager server and the agents is encrypted, but the certificate authenticity is not verified. For full security, you must configure the agents to verify the Cloudera Manager server certificate. If you are using a server certificate signed by an internal certificate authority (CA), you must configure the agents to trust that CA:

  1. On each agent host (including the Cloudera Manager Server host), open the /etc/cloudera-scm-agent/config.ini configuration file, and then uncomment and set the following property: 
    verify_cert_file=/opt/cloudera/security/pki/rootca.pem

    Alternatively, you can edit the config.ini file on one host, and then copy it to the other hosts because this file by default does not contain host-specific information. If you have modified properties such as listening_hostname or listening_ip address in config.ini, you must edit the file individually on each host.

  2. Restart the Cloudera Manager agents. On each agent host (including the Cloudera Manager Server host), run the following command:
    • RHEL 7 compatible: 
      sudo systemctl restart cloudera-scm-agent
    • RHEL 6 compatible, SLES, Ubuntu:
    • sudo service cloudera-scm-agent restart
  3. Verify that the Cloudera Manager server and agents are communicating. In the Cloudera Manager Admin Console, go to Hosts > All Hosts. If you see successful heartbeats reported in the Last Heartbeat column after restarting the agents and management service, TLS verification is working properly. If not, check the agent log (/var/log/cloudera-scm-agent/cloudera-scm-agent.log) for errors.

Configure Agent Certificate Authentication

Without certificate authentication, a malicious user can add a host to Cloudera Manager by installing the Cloudera Manager agent software and configuring it to communicate with Cloudera Manager Server. To prevent this, you must configure Cloudera Manager to trust the agent certificates.

Step 1: Export the Private Key to a File

On each Cloudera Manager Agent host, use the keytool utility to export the private key and certificate to a PKCS12 file, which can then be split up into individual key and certificate files using the openssl command:

  1. Export the private key and certificate: 
    sudo $JAVA_HOME/bin/keytool -importkeystore -srckeystore /opt/cloudera/security/pki/$(hostname -f).jks -destkeystore /opt/cloudera/security/pki/$(hostname -f)-key.p12 -deststoretype PKCS12 -srcalias $(hostname -f)
  2. Use the openssl command to export the private key into its own file: 
    sudo openssl pkcs12 -in /opt/cloudera/security/pki/$(hostname -f)-key.p12 -nocerts -out /opt/cloudera/security/pki/$(hostname -f).key
  3. Create a symbolic link for the .key file: 
    sudo ln -s /opt/cloudera/security/pki/$(hostname -f).key /opt/cloudera/security/pki/agent.key

    This allows you to use the same /etc/cloudera-scm-agent/config.ini file on all agent hosts rather than maintaining a file for each agent.

Step 2: Create a Password File

The Cloudera Manager agent obtains the password from a text file, not from a command line parameter or environment variable. The password file allows you to use file permissions to protect the password. For example, run the following commands on each Cloudera Manager Agent host, or run them on one host and copy the file to the other hosts:

Create and secure the file containing the password used to protect the private key of the Agent:
  1. Use a text editor to create a file called /etc/cloudera-scm-agent/agentkey.pw that contains the password.
  2. Change ownership of the file to root: 
    sudo chown root:root /etc/cloudera-scm-agent/agentkey.pw
  3. Change the permissions of the file: 
    sudo chmod 440 /etc/cloudera-scm-agent/agentkey.pw

Step 3: Configure the Agent to Use Private Keys and Certificates

On a Cloudera Manager Agent, open the /etc/cloudera-scm-agent/config.ini configuration file, uncomment and edit the following properties:
Property Example Value Description
client_key_file /opt/cloudera/security/pki/agent.key Path to the private key file.
client_keypw_file /etc/cloudera-scm-agent/agentkey.pw Path to the private key password file.
client_cert_file /opt/cloudera/security/pki/agent.pem Path to the client certificate file.

Copy the file to all other cluster hosts. If you have modified properties such as listening_hostname or listening_ip address in config.ini, you must edit the file individually on each host.

Step 4: Enable Agent Certificate Authentication

  1. Log in to the Cloudera Manager Admin Console.
  2. Select Administration > Settings.
  3. Click the Security category.
  4. Configure the following TLS settings:
    Setting Description
    Use TLS Authentication of Agents to Server Select this option to enable TLS authentication of agents to the server.
    Cloudera Manager TLS/SSL Certificate Trust Store File Specify the full filesystem path to the jssecacerts file located on the Cloudera Manager Server host. For this example, set the value to: 
    <JAVA_HOME>/jre/lib/security/jssecacerts
    Replace <JAVA_HOME> with the path to the Oracle JDK.
    Cloudera Manager TLS/SSL Certificate Trust Store Password Specify the password for the jssecacerts truststore.
  5. Click Save Changes to commit the changes.

Step 5: Restart Cloudera Manager Server and Agents

  1. On the Cloudera Manager server host, restart the Cloudera Manager server:
    • RHEL 7 compatible: 
      sudo systemctl restart cloudera-scm-server
    • RHEL 6 compatible, SLES, Ubuntu:
    • sudo service cloudera-scm-server restart
  2. On every agent host, restart the Cloudera Manager agent:
    • RHEL 7 compatible: 
      sudo systemctl restart cloudera-scm-agent
    • RHEL 6 compatible, SLES, Ubuntu:
    • sudo service cloudera-scm-agent restart

Step 6: Verify that Cloudera Manager Server and Agents are Communicating

In the Cloudera Manager Admin Console, go to Hosts > All Hosts. If you see successful heartbeats reported in the Last Heartbeat column after restarting the agents and server, TLS certificate authentication is working properly. If not, check the agent log (/var/log/cloudera-scm-agent/cloudera-scm-agent.log) for errors.

For example, you might see the following error:

WrongHost: Peer certificate commonName does not match host, expected 192.0.2.155, got cdh-1.example.com
[02/May/2018 15:04:15 +0000] 4655 MainThread agent        ERROR    Heartbeating to 192.0.2.155:7182 failed

For this scenario, make sure that your DNS and /etc/hosts file are configured correctly, and that your server_host parameter in /etc/cloudera-scm-agent/config.ini uses the Cloudera Manager Server hostname, and not IP address.