Automating Splunk deployment for RedHat/Centos (poor man’s edition)

I pulled this out of the archives , on request notice this was originally developed for Splunk 6.2.x and RHEL 7.0. Please review the details make sure it is suitable for you and TEST. If I can talk you out of doing things this way I would. Salt is a great way to manage app config its free and just awesome.

Title: Splunk Universal Forwarder Version 6.2.3+ Red Hat Enterprise Linux 7

Author: Ryan Faircloth 

Summary: Using repositories for version managment of the Splunk Universal Forwarder assists in ensuring managed Red Hat and compatible linux  systems are using the approved version of the software at all times. 


## Setup the repository server ##
1. Install createrepo  and nginx ``` yum install createrepo apache2 ```
3. Create a user to work with the repository 

	sudo adduser  repouser 
3. Change user to our repouser user all commands for the repository should be executed using this ID 

	 sudo su - repouser

## Generate GPG Keys ##
1. Change user to our repouser user all commands for the repository should be executed using this ID 

	sudo su - repouser 
2. Create the default configuration for gpg by running the command 

	gpg --list-keys
3. Edit ~/.gnupg/gpg.conf 
	* uncomment the line ``` no-greeting ```
	* add the following content to the end of the file 
	# Prioritize stronger algorithms for new keys.
	default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 BZIP2 ZLIB ZIP UNCOMPRESSED
	# Use a stronger digest than the default SHA1 for certifications.
	cert-digest-algo SHA512
4. Generate a new key with the command ``` gpg --gen-key ```
5. Select the folowing options ON CENTOS/RHEL this procedure must be executed on the console or SSH having logged in as the repouser
	1. Type of key "(1) RSA and RSA (default)"
	2. Key size "4096"
	3. Expires "10y"
	4. Confirm "Y"
	5. Real Name "Splunk local repository"
	6. Email address on repository contact this generally should be an alias or distribution list
	7. Leave the comment blank
	8. Confirm and "O" to Okay
	9. Leave passphrase blank and confirm, a key will be generated not the sub KEY ID in the following example * E507D48E * 

	gpg: checking the trustdb
	gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
	gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
	gpg: next trustdb check due at 2025-05-24
	pub   4096R/410E1699 2015-05-27 [expires: 2025-05-24]
    	  Key fingerprint = 7CB8 81A9 E07F DA7B 83FF  2E1B 8B31 DA83 410E 1699
	uid                  Splunk local repository <>
	sub   4096R/E507D48E 2015-05-27 [expires: 2025-05-24]
10. Export the signing keys public component save this content for use later

	gpg --export --armor KEY_ID >~/ 
11. Install the new key into the RPM database

sudo cp ~/ /etc/pki/rpm-gpg/RPM-GPG-KEY-splunkrepo
sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-splunkrepo
12. Configure RPM signing with the new key

echo "%_signature gpg" > ~/.rpmmacros
echo "%_gpg_name splunkrepo" >> ~/.rpmmacros

13. Create a repository

mkdir /opt/splunkrepo
cp splunkforwarder*.rpm /opt/splunkrepo
createrepo /opt/splunkrepo
14. Configure the local repository create the following configuration /etc/yum.repos.d/splunk.repo

name=splunk repository
15. Test the local repository by installing splunkforwarder

sudo yum update
sudo yum install splunkforwader
Note: Create a configuration RPM refer to and for more information do not run as root sudo to repouser
17.  Prepare the rpm tree ``` rpmdev-setuptree ```
18.  Create a spec file with the following content ~/splunkforwarder-baseconfig.spec

# This spec file is Copyright 2010, My Company, Inc.
Summary: My Company general configuration RPM
Name: splunkforwarder-baseconfig
Version: 1
Release: 3
License: Copyright 2010, My Company, Inc.
Group: MyCompany/Configs
Packager: Packager Name <>
requires: splunkforwarder
BuildArch: noarch
This RPM provides general services and security configuration for My Company.

%triggerin -- splunkforwarder
/opt/splunkforwarder/bin/splunk enable boot-start --accept-license --answer-yes 
service splunk stop
if [ -d "/opt/splunkforwarder/etc/apps/org_all_deploymentclient/local" ]
    echo "Directory /opt/splunkforwarder/etc/apps/org_all_deploymentclient/local exists."
    mkdir -p /opt/splunkforwarder/etc/apps/org_all_deploymentclient/local    
echo #Base deployment configuration >/opt/splunkforwarder/etc/apps/org_all_deploymentclient/local/deploymentclient.conf
echo [deployment-client] >>/opt/splunkforwarder/etc/apps/org_all_deploymentclient/local/deploymentclient.conf
#echoclientName  >>/opt/splunkforwarder/etc/apps/org_all_deploymentclient/local/deploymentclient.conf
echo [deployment-client] >>/opt/splunkforwarder/etc/apps/org_all_deploymentclient/local/deploymentclient.conf
echo targetUri = >>/opt/splunkforwarder/etc/apps/org_all_deploymentclient/local/deploymentclient.conf

service splunk start

%triggerun -- splunkforwarder
if [ $1 -eq 0 -a $2 -gt 0 ] ; then
 /opt/splunkforwarder/bin/splunk stop
 /opt/splunkforwarder/bin/splunk disable boot-start
 rm -Rf /opt/splunkforwarder/etc/apps/org_all_deploymentclient

18.  Build the RPM ``` rpmbuild -sign -ba splunkforwarder-baseconfig.spec ```
19. Copy the RPM to the repository cp ~/rpmbuild/RPMS/noarch/splunkforwarder-baseconfig-1-3.noarch.rpm / /opt/splunkrepo
20. Update repository DB ``` createrepo /opt/splunkrepo ```
21. Test the rpms

yum update
yum install splunkforwarder-baseconfig
22. Configure a web server (Apache) for use as a repository server
23.  Set permissions on the repository folder ``` chmod -R 755 /opt/splunkrepo ```
24. Create the web server configuration file with the following contents /etc/http/conf.d/splunkrepo.conf

Alias /splunkrepo/ "/opt/splunkrepo/"

<Directory "/opt/splunkrepo">
   Options Indexes FollowSymLinks MultiViews
   AllowOverride All
   Require local
   Order allow,deny
   Allow from all
25. Reload (or restart) the web server ```service httpd reload ```
26. Test `` lynx http://localhost/splunkrepo/repodata/repomd.xml ```
27. Enable the new repository on the first test client

sudo yum-config-manager --add-repo http://localhost/splunkrepo
sudo yum update
sudo yum install splunkforwarder-baseconfig

Splunk the server and the enpoint aka “All the Things”

I’m sharing something today that has been available thanks to many in white papers and presentations dealing with identification of malicious code and activities in your windows event data. Shout out to everyone from our “friends” at the NSA, to Splunk .Conf presenters and just to name a few.

The PDF attached is a portion of the next evolution of the Use Case Repository I maintain at Splunk. Along with the reference TAs and inputs, this will allow you to quickly and consistently collect very valuable data supporting security use cases at multiple levels of maturity. If it seems like too much don’t work Splunk Pro Services and partners are able to help you get this visibility just contact your account team.

Standard disclaimer, this is a blog post, I built the content from public non-warrantied information, and this is still public non-warrantied information, your situation might not match the advice given.


Good Assets and Identities make for big bundles

Having great and informative data will make for some hefty lookups. I’ve heard from a few customers that run into this rather than plan for it so let us talk about the levers we need to pull.

  • Don’t wait around upgrade to Splunk Enterprise 6.5.2+ Now is the time
  • Don’t wait any longer upgrade to Splunk Enterprise Security 4.5.1 the dev team invested in improvements to assets and identities lookups that also improve by decreasing the size of the merged lookups.
  • Update server.conf on the indexers and search head cluster peers.


max_content_length = 1610612736 # 1.5 GB

  • Update distsearch.conf to better replication on the SH/SHC
# 1.5 GB with encoding room this will increase the memory utilization while decreasing CPU utilization
maxMemoryBundleSize = 1700 
#1.5 GB to match server.conf on the other side
maxBundleSize = 1536

RSYSLOG read the docs

Ok, I said posts in threes so here it is. We all know RYSLOG config is much more painful than syslog-ng but for reasons beyond all of our control, it is readily available for more customers than syslog-ng is today. Thanks to Splunk users I want to share a couple links to better doc to make this not so awful

  • RedHat
  • Usenix

thank you @mattymo and @lowell via Splunk Slack chat

Unbelievably simple (ipfix|(net|j|s)flow) collection

Do blog posts come in threes, keep watching to find out? Yesterday I gave you the run down on a new way to collect syslog. Today I’m going to spend some time on a simple low cost and performant way to collect flow data.

  • At least two indexers with http event collector, more = better. For this use case it is not appropriate to utilize dedicated HEC servers.
  • One http load balancer, I use HA proxy. You can certainly use the same one from our rsyslog configuration.
  • Optional one UDP load balancer such as NGNIX. I am not documenting this setup at this time.
  • One ubuntu 16.04 VM

Basic Setup

  1. Follow docs, to setup HTTP event collector on your indexers, note if your indexers are clustered docs does not cover this, you must create the configuration manually be sure to generate a unique GUID manually. Clusters environments can use the sample configuration below: IMPORTANT ensure your data indexes AND _internal are allowed for the token
  2. [http] 
  3. Follow documentation for your load balancer of choice to create a http VIP with https back end servers. HEC listens on 8088 by default.
  4. Install stream for the independent per Docs
  5. Kill stream if its running “killall -9 streamfwd”
  6. Remove the init script
    1. update-rc.d -f streamfwd remove”
    2. rm /etc/init.d/streamfwd
  7. Create a new service unit file for systemd /etc/systemd/system/streamfwd.service
    Description= Splunk Stream Dedicated Service
    ExecStart=/opt/streamfwd/bin/streamfwd -D
  8. Enable the new service “systemctl enable streamfwd”
  9. Create/update the streamfwd.conf replacing GUID VIP and INTERFACE
    1. [streamfwd]
      httpEventCollectorToken = <GUID>
      indexer.0.uri= <HEC VIP>
      netflowReceiver.0.ip = <INTERFACE TO BIND>
      netflowReceiver.0.port = 9995
      netflowReceiver.0.decoder = netflow
  10. Create/update the inputs.conf ensure the URL is correct for the location of your stream app
  11. [streamfwd://streamfwd]
    splunk_stream_app_location =
  12. Start the streamfwd “systemctl start streamfwd”
  13. Login to the search head where Splunk App for Stream is Installed
  14. Navigate to Splunk App for Stream –> Configuration –> Distributed Forwarder Managment
  15. Click Create New Group
  16. Enter Name as “INFRA_NETFLOW”
  17. Enter a Description
  18. Click Next
  19. Enter “INFRA_NETFLOW” as the rule and click next
  20. Click Finish without selecting options
  21. Navigate to Splunk App for Stream –> Configuration –> Configure Streams
  22. Click New Stream select netflow as the protocol (this is correct for netflow/sflow/jflow/ipfix
  23. Enter Name as “INFRA_NETFLOW”
  24. Enter a Description and click next
  25. No Aggregation and click next
  26. Deselect any fields NOT interesting for your use case and click next
  27. Optional develop filters to reduce noise from high traffic devices and click next
  28. Select the index for this collection and click enable then click next
  29. Select only the Infra_netflow group and Create_Stream
  30. Configure your NETFLOW generator to send records to the new streamfwd

Validation! search the index configured in step 27

Building a more perfect Syslog Collection Infrastructure

A little while back I created a bit of code to help get data from linux systems in real time where the Splunk Universal Forwarder could not be installed. At the time we had a few limitations the biggest problem being time stamps were never parsed only “current” time on the indexer could be used.  Want to try out version 2 lets get started! First let me explain what we are doing

If you manage a Splunk environment with high rate sources such as a Palo Alto firewall or Web Proxy you will notice that events are not evenly distributed over the indexers because the the data is not evenly balanced across your aggregation tier. The reasons for this are boiled down to “time based load balancing” in Larger environments the universal forwarder may not be able to split by time to distribute a high load. So what is an admin to do? Lets look for a connection load balancing solution. We need to find a way to switch from “SYSLOG” to HTTP(s) so we can utilize a proper load balancer. How will we do this?

  1. Using containers we will dedicate one or more instance of RSYSLOG for each “type” of data,
  2. Use a custom plugin to package and forward batches of events over http(s)
  3. Use a load balancer configured for least connected round robin to balance the batches of events

What you need

  • At least two indexers with http event collector, more = better. The “benefits” of this solution require collection on the indexer dedicated collectors will not be a adequate substitute
  • One load balancer, I use HA Proxy
  • One syslog collection server with rsyslog 8.24+ host I use LXC instances hosted on proxmox. Optimal deployment will utilize 1 collector per source technology. For example 1 instance collecting for Cisco IOS and another for Palo Alto Firewalls. Using advanced configuration and filters you can combine several low volume source.
  • A GUID if you need one generated there are many ways this one is quick and easy

Basic Setup

  1. Follow docs, to setup HTTP event collector on your indexers, note if your indexers are clustered docs does not cover this, you must create the configuration manually be sure to generate a unique GUID manually. Clusters environments can use the sample configuration below:
  2. Follow documentation for your load balancer of choice to create a http VIP with https back end servers. HEC listens on 8088 by default
  3. Grab the code and configuration examples from bitbucket
    1. Deploy the script to /opt/rsyslog/ ensure the script is executable
    2. Review rsyslogd.d.conf.example and your configuration in /etc/rsyslog.d/00-splunkhec.conf replace the GUID and IP with your correct values
    3. Restart rsyslog

What to expect, My hope data balance Zen.

HTTP Event Collector inputs.conf example deployed via master-apps


Example /etc/rsyslog.d/00-splunk.conf

This example will listen on 514 TCP and UDP sending events via http, be sure to replace the GUID and ip address

input(type="imudp" port="514" ruleset="default_file")
input(type="imptcp" port="514" ruleset="default_file")

       binary="/opt/rsyslog/ DAA61EE1-F8B2-4DB1-9159-6D7AA5220B21 --sourcetype=syslog --index=main" 

Example HAProxy Configuration 1.7 /etc/haproxy/haproxy.cfg


        log /dev/log    local0
        log /dev/log    local1 notice
        chroot /var/lib/haproxy
        stats socket /run/haproxy/admin.sock mode 660 level admin
        stats timeout 30s
        user haproxy
        group haproxy
        # Default SSL material locations
        ca-base /etc/ssl/certs
        crt-base /etc/ssl/private
        # Default ciphers to use on SSL-enabled listening sockets.
        # For more information, see ciphers(1SSL).
        ssl-default-bind-ciphers kEECDH+aRSA+AES:kRSA+AES:+AES256:RC4-SHA:!kEDH:!LOW:!EXP:!MD5:!aNULL:!eNULL
        log     global
        mode    http
        option  httplog
        option  dontlognull
        timeout connect 5000
        timeout client  50000
        timeout server  50000
        errorfile 400 /etc/haproxy/errors/400.http
        errorfile 403 /etc/haproxy/errors/403.http
        errorfile 408 /etc/haproxy/errors/408.http
        errorfile 500 /etc/haproxy/errors/500.http
        errorfile 502 /etc/haproxy/errors/502.http
        errorfile 503 /etc/haproxy/errors/503.http
        errorfile 504 /etc/haproxy/errors/504.http
listen  stats   
        bind            *:1936
        mode            http
        log             global
        maxconn 10
        clitimeout      100s
        srvtimeout      100s
        contimeout      100s
        timeout queue   100s
        stats enable
        stats hide-version
        stats refresh 30s
        stats show-node
        stats auth admin:password
        stats uri  /haproxy?stats
frontend localnodes
    bind *:8088
    mode http
    default_backend nodes
backend nodes
    mode http
    balance leastconn
    option forwardfor
    http-request set-header X-Forwarded-Port %[dst_port]
    http-request add-header X-Forwarded-Proto https if { ssl_fc }
    option httpchk
    server idx2 ssl verify none check 
    server idx1 ssl verify none check 

Making Splunk Certified Apps

As a developer of “Apps” for the Splunk platform; I have been very eager to automate more tedious tasks including build and static code analysis. Today our very awesome development community has access to a new tool App Inspect. The new python based extensible framework will allow your automated build process to validate key issues and prepare for formal certification for Public apps on Splunk Base, or assure quality for internally developed apps. The process example can easily be ported to the tool section of your choice allowing for effective version control and testing of applications built on the Splunk platform.

To help you get started I’ve developed an example using our partner’s tools at Atlassian.

  • Bitbucket repository containing the source
  • CMAKE build script for packaging and versioning
  • Bitbucket pipelines integration using docker to ensure a clean package and execute validation
  • Publish to AWS S3 as a package repository before manual publishing to Splunk Base

Getting started review this is my first and most complete example.

  • CMakeLists.txt controls the build process
  • src/ contains the applications source
  • src/default/ is the template for app.conf our build will update this file with the correct version tag supplied by git
  • bitbucket-pipelines.yml controls the pipelines automated integration process
    • Retrieve and deploy the latest docker image with build tools and app inspect
    • Package the app
    • Push to S3

Try it yourself!

%d bloggers like this: