1 Introduction

Splunk is an enterprise software that makes machine data accessible, usable and valuable to anyone. Splunk makes it simple to collect, analyse, and act upon the value of the data generated by an enterprise's technology infrastructure. Splunk helps users turn machine data into operational intelligence.

Such a powerful tool requires reliable and powerful support. The Kemp LoadMaster delivers an exceptional, cost-effective and easy to use solution that, by employing Adaptive Load Balancing, balances requests across Splunk servers.

When deployed as a pair, two LoadMasters give the security of High Availability (HA). HA allows two physical or virtual machines to become one logical device. Only one of these units is ever handling traffic at any particular moment. One unit is active and the other is a hot standby (passive). This provides redundancy and resiliency, meaning if one LoadMaster goes down for any reason, the hot standby can become active, therefore avoiding any downtime. For more information on HA please refer to: High Availability (HA), Feature Description.

1.1 Document Purpose

This document provides guidance on how to deploy Splunk with a Kemp LoadMaster. The Kemp Support Team is available to provide solutions for scenarios not explicitly defined.

The Kemp support site can be found at: https://support.kemptechnologies.com.

1.2 Intended Audience

This document is intended to be used by anyone deploying Splunk with a Kemp LoadMaster.

2 Template

Kemp has developed a template containing our recommended settings for this workload. You can install this template to help create Virtual Services (VSs) because it automatically populates the settings. You can use the template to easily create the required VSs with the recommended settings. For some workloads, additional manual steps may be required such as assigning a certificate or applying port following, these steps are covered in the document, if needed.

You can remove templates after use and this will not affect deployed services. If needed, you can make changes to any of the VS settings after using the template.

Download released templates from the following page: LoadMaster Templates.

For more information and steps on how to import and use templates, refer to the Virtual Services and Templates, Feature Description on the Kemp Documentation page.

3 Architecture

4 Configure Splunk Virtual Services

The environment in which Splunk is deployed determines which of the following setups should be used.

4.1 Enable Subnet Originating Requests Globally

It is best practice to enable the Subnet Originating Requests option globally.

In a one-armed setup (where the Virtual Service and Real Servers are on the same network/subnet) Subnet Originating Requests is usually not needed. However, enabling Subnet Originating Requests should not affect the routing in a one-armed setup.

In a two-armed setup where the Virtual Service is on network/subnet A, for example, and the Real Servers are on network B, Subnet Originating Requests should be enabled on LoadMasters with firmware version 7.1-16 and above.

When Subnet Originating Requests is enabled, the Real Server sees traffic originating from 10.20.20.21 (LoadMaster eth1 address) and responds correctly in most scenarios.

With Subnet Originating Requests disabled, the Real Server sees traffic originating from 10.0.0.15 (LoadMaster Virtual Service address on eth0) and responds to eth0 which could cause asymmetric routing.

When Subnet Originating Requests is enabled globally, it is automatically enabled on all Virtual Services. If the Subnet Originating Requests option is disabled globally, you can choose whether to enable Subnet Originating Requests on a per-Virtual Service basis.

To enable Subnet Originating Requests globally, follow the steps below:

1. In the main menu of the LoadMaster User Interface (UI), go to System Configuration > Miscellaneous Options > Network Options.

2. Select the Subnet Originating Requests check box.

4.2 Splunk Virtual Service

The following are the steps involved and the values required to configure Splunk Virtual Service:

1. In the main menu of the LoadMaster Web User Interface (WUI), go to Virtual Services > Add New.

2. Enter a valid IP address in the Virtual Address text box.

3. Enter 443 in the Port text box.

4. Enter a recognizable Service Name, for example Splunk.

5. Ensure tcp is selected as the Protocol.

6. Click Add this Virtual Service.

7. Enter the details shown in the following table:

Section	Option	Value	Comment
Standard Options	Transparency	Deselected
	Persistence Mode	None
	Scheduling Method	Round robin
SSL Properties	SSL Acceleration	Enabled Reencrypt	A wildcard certificate allows secure connections to be established with a request URL in the format of *.example.com. With this approach, a single certificate secures traffic for all clients in a multi-tenant environment.
	Supported Protocols	TLS1.0 TLS1.1 TLS1.2 TLS1.3	While this workload may not support TLS1.3 yet, Kemp recommend enabling it for future proofing.
	Cipher Set	Best Practices	For further information on cipher sets, please refer to the SSL Accelerated Services, Feature Description.
Advanced Properties	Content Switching	Disabled
	Add HTTP Headers	Legacy Operation (X-ClientSide)
	Redirect URL	https://%h%s	Click Add HTTP Redirector
Real Servers	Real Server Check Method	HTTPS Protocol
	Checked Port	8000
	HTTP Method	HEAD

Users should note that clicking the Set Redirect URL button, automatically creates a redirect Virtual Service on Port 80.

8. Add the Real Servers:

a) Click the Add New button.

b) Enter the IP address of the AX Server.

c) Enter 443 as the Port.

d) Click Add this Real Server. Click OK to the pop-up message.

e) Repeat steps b) to d) above to add more Real Servers as needed, based on the environment.

4.3 Splunk HTTP (Redirect) Virtual Service

1. This Virtual Service is automatically created when users click the Set Redirect URL button while configuring the Splunk Virtual Service in the Splunk Virtual Service section.

4.4 Splunk Syslog UDP Virtual Service

The following are the steps involved and the values required to configure the Splunk Syslog UDP Virtual Service:

1. In the main menu of the LoadMaster Web User Interface (WUI), go to Virtual Services > Add New.

2. Enter a valid IP address in the Virtual Address text box.

3. Enter 514 in the Port text box.

4. Enter a recognizable Service Name, for example Splunk Syslog udp.

5. Ensure udp is selected as the Protocol.

6. Click Add this Virtual Service.

7. Enter the details shown in the following table:

Section	Option	Value
Standard Options	Transparency	Enabled
	Persistence Mode	Source IP Address
	Prersistence Timeout	1 Minute
	Scheduling Method	Weighted round robin
Real Servers	Real Server Check Method	ICMP Ping

8. Add the Real Servers:

a) Click the Add New button.

b) Enter the IP address of the AX Server.

c) Enter 514 as the Port.

d) Click Add this Real Server. Click OK to the pop-up message.

e) Repeat steps b) to d) above to add more Real Servers as needed, based on the environment.

References

1. Unless otherwise specified, the following documents can be found at: http://kemptechnologies.com/documentation.

Virtual Services and Templates, Feature Description.

High Availability (HA), Feature Description

SSL Accelerated Services, Feature Description

Last Updated Date

This document was last updated on 03 March 2022.