Install Splunk in a multi-instance cluster

This document will guide the users through the installation process for a multi-tier server, recommended for larger environments with huge amounts of data (in this case, Wazuh alerts) and users.

Prerequisites

  1. A Wazuh manager cluster.

  2. A Splunk cluster.

Note

Most of the commands described below need to be executed with root user privileges.

Note

To deploy a Splunk cluster, visit the Official Splunk Documentation.

Warning

By following this guide, users will learn how to install and configure Wazuh in an already created Splunk cluster. All Splunk related configuration is in their Official Documentation, and it is assumed that a Splunk cluster installation and configuration has been already done.

The structure of a basic Splunk Cluster is formed by the following elements:

  • The search head instances will be in charge of all the searching functionality, and they will look for data on the search peers’ indexes. These instances won’t have any indexes at all. The Wazuh App will be installed in these instances.

  • The search peer instances (or indexers) collect all the Wazuh data and store it in the form of indexes. These instances are connected to the search heads so they can consult the peer’s indexes.

  • The forwarder runs on the Wazuh manager instance, it reads local data and sends it to the indexer.

  • The deployer instance installs and configures the Wazuh App into every search head instance at the same time.

Install and configure Splunk enterprise indexer instances

Note

  • Splunk is not open source software and it requires a registered user and license in order to work. You can also use a free trial license.

  • This guide will install and configure Splunk 8.2.6. If you intend to configure a different version of Splunk with Wazuh, change the Splunk version number in the requests for the configuration files and Wazuh app for Splunk. For example, if you intend to configure Splunk 8.2.2:

    # curl -so /opt/splunk/etc/system/local/indexes.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.6/setup/indexer/indexes.conf
    

    Becomes

    # curl -so /opt/splunk/etc/system/local/indexes.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.2/setup/indexer/indexes.conf
    

Each instance can be configured on different hosts following the steps described below:

Ensure Splunk is already installed in /opt/splunk and start the service:

# /opt/splunk/bin/splunk start

Note

You will be prompted for a username and password for the administrator user.

After this step the Splunk Web service will be listening to port 8000. You can browse http://<your-instance-ip>:8000 in order to access the Web GUI.

Configuring the Splunk indexer instances

In the Splunk master instance, users will make the configuration that will be pushed to the rest of the indexers.

  1. Create the files inputs.conf:

    # touch /opt/splunk/etc/master-apps/_cluster/local/inputs.conf
    
  2. Paste the following block of code in inputs.conf

    [splunktcp://<INDEXER_PORT>]
    connection_host = ip
    disabled = 0
    
    [SSL]
    serverCert = $SPLUNK_HOME/etc/auth/server.pem
    sslPassword = password
    
    • INDEXER_PORT is the receiving port of the Splunk indexer earlier configured in receiving.

    • serverCert is the path to the Splunk default server certificate.

    • $SPLUNK_HOME is the Splunk installation directory. The default directory is /opt/splunk.

    • sslPassword is the password of the certificate. The default password is “password”.

  3. To create and configure the indexes.conf file, execute the following command:

    # curl -so /opt/splunk/etc/master-apps/_cluster/local/indexes.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.6/setup/indexer/indexes.conf
    
  4. Apply the cluster bundle:

    # /opt/splunk/bin/splunk apply cluster-bundle
    
  5. Restart the Splunk Service:

    # /opt/splunk/bin/splunk restart
    

Install and configure Splunk forwarder instances

A Splunk forwarder is required in order to send alerts to the Splunk indexers. Depending on the type of architecture that you’re installing, the Splunk forwarder is configured differently.

  1. Download the Splunk package from its official website. The versions of Splunk compatible with Wazuh and the Wazuh app for Splunk can be found here.

    Note

    • Splunk is not open source software and it requires a registered user and license in order to work. You can also use a free trial license.

    • This guide will install and configure Splunk 8.2.6. If you intend to configure a different version of Splunk with Wazuh, change the Splunk version number in the requests for the configuration files and Wazuh app for Splunk. For example, if you intend to configure Splunk 8.2.2:

      # curl -so /opt/splunk/etc/system/local/indexes.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.6/setup/indexer/indexes.conf
      

      Becomes

      # curl -so /opt/splunk/etc/system/local/indexes.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.2/setup/indexer/indexes.conf
      
  2. Install the Splunk forwarder package on all the Wazuh manager nodes:

    # yum install splunkforwarder-package.rpm
    
    # dpkg --install splunkforwarder-package.deb
    

Configuring the Splunk forwarder instances

The following files will be configured on all forwarder instances:

  • inputs.conf: This file specifies the options for reading alerts from the alerts.json file.

  • outputs.conf: This file is for pointing events to indexers. It can be a single indexer or a cluster of indexers. If it is a cluster of indexers, load balancing has to be configured for the forwarders.

  • props.conf: This file provides format and transforming options on the fields of the data to be indexed.

Creating the configuration files

  1. Download and insert the inputs.conf template:

    # curl -so /opt/splunkforwarder/etc/system/local/inputs.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.6/setup/forwarder/inputs.conf
    
  2. Set the Wazuh manager hostname:

    # sed -i "s:MANAGER_HOSTNAME:$(hostname):g" /opt/splunkforwarder/etc/system/local/inputs.conf
    
  3. Create outputs.conf:

    # touch /opt/splunkforwarder/etc/system/local/outputs.conf
    
  4. Fill outputs.conf with the code block below:

    [indexer_discovery:cluster1]
    pass4SymmKey = changeme
    master_uri = https://<master_ip>:<port>
    
    [tcpout:cluster1_tcp]
    indexerDiscovery = cluster1
    clientCert = /opt/splunkforwarder/etc/auth/server.pem
    sslRootCAPath = /opt/splunkforwarder/etc/auth/ca.pem
    sslPassword = password
    
    [tcpout]
    defaultGroup = cluster1_tcp
    

    Where:

    <master_ip> references the indexer master IP address.

    <port> references the indexers master management port.

    changeme references the security key used with communication between the cluster master and the forwarders..

    cluster1 references the <name> set in the indexerDiscovery attribute in the [tcpout:<target_group>] stanza.

    In the [tcpout:<target_group>] stanza, set the indexerDiscovery attribute, instead of the server attribute that you would use to specify the receiving peer nodes if you were not enabling indexer discovery. With indexer discovery, the forwarders get their list of receiving peer nodes from the master, not from the server attribute. If both attributes are set, indexerDiscovery takes precedence.
  5. Download and insert the props.conf template:

    # curl -so /opt/splunkforwarder/etc/system/local/props.conf https://raw.githubusercontent.com/wazuh/wazuh-splunk/v4.3.0-8.2.6/setup/forwarder/props.conf
    
  6. To save all the changes, start the Splunk forwarder:

    # /opt/splunkforwarder/bin/splunk start
    

Note

This command will make a Splunk General Terms appear that will have to be accepted, and then, will ask for a series of information such as:

  • Administrator name

  • Password

Note

You can check the state of the cluster executing from the cluster master node:

# /opt/splunk/bin/splunk show cluster-bundle-status

Set up data forwarding

  1. Point each Splunk forwarder output to a Splunk indexer with the following command:

    # /opt/splunkforwarder/bin/splunk add forward-server <INDEXER_IP>:<INDEXER_PORT>
    
    • INDEXER_IP is the IP address of the Splunk indexer cluster master.

    • INDEXER_PORT is the port of the Splunk indexer earlier configured in receiving.

    Note

    This command will ask for a series of information such as:

    • Splunk username (created previously)

    • Password of Splunk username

  2. Start the Splunk forwarder service:

    # /opt/splunkforwarder/bin/splunk start
    

The next step is installing the Wazuh App in the search heads instances and configuring them to use the Splunk services.

  • You can find useful Splunk CLI commands in the official documentation.

  • To learn more about the Splunk distributed search, check out this article from the official documentation.