I recently had to get the Forwarders installed and there are no detailed steps in the Splunk docs for Solaris 11. If you need Solaris 10 steps, see my post here.

1) There are two installation options and platforms supported by Splunk; using pkg and tar on SPARC and x64 CPUs. The platform/CPU type is at the end of the filename shown below. The steps below cover both types of installation scenarios. Choose the steps for the way in which you want to install and the platform you have. There is a Universal Forwarder for SPARC and x64 (Intel/AMD) CPUs. Be sure to su – root before you start, or use sudo in front of the commands.

a) Native pkg (as in .p5p) formatted binary – easy to manage and upgrade, software included in inventory and vuln scans. Installed using pkg:
splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p
splunkforwarder-8.2.3-cd0848707637-solaris-sparc.p5p

b) Extracted via tar – software not seen by inventory and vuln scans, only the running splunkd process identifies it in scans (but not the version running). Installed using tar:
splunkforwarder-8.2.3-cd0848707637-SunOS-x86_64.tar.Z
splunkforwarder-8.2.3-cd0848707637-SunOS-sparc.tar.Z

2) Verify that you have the required libc installed.
> pvs /usr/lib/libc.so.1 | grep SUNW_1.22.7
> pvs /usr/lib/libc.so.1 (to get a list of all libc versions)

3) Backup your files. If you have any locally customized .conf files in the following folders, save a copy now. Note that some older forwarders
may not use upper case letters in the path.

/opt/splunkforwarder/etc/apps/SplunkUniversalForwarder/local/
/opt/splunkforwarder/etc/system/local/

4) If an existing Forwarder is running, identify your Splunk index. You will need this value along with your hostname, IP address and platform later.
> cat /opt/splunkforwarder/etc/system/local/inputs.conf | grep index
> hostname
> ifconfig -a | grep inet (or just ifconfig -a if you have multiple NICs plumbed)
> uname -a

5) Check for existing version and state.
If the existing Forwarder was installed with pkg:
> pkg list | splunk
> pkg info -r splunkforwarder | egrep -i “Summary|Version”
> /opt/splunkforwarder/bin/splunk status
> ps aevx | grep splunkd

If the existing Forwarder was installed with tar:
> /opt/splunkforwarder/bin/splunk version
> /opt/splunkforwarder/bin/splunk status
> ps aevx | grep splunkd

6) Stop the currently installed Universal Forwarder and then remove it.
> /opt/splunkforwarder/bin/splunk stop

If installed via pkg:
> pkg uninstall splunkforwarder
> rm /etc/init.d/splunk

If installed via tar:
> cd /opt/
> rm -r splunkforwarder
> rm /etc/init.d/splunk

7) Make sure the Splunk sockets are no longer in use or locked. Copy/paste each line below one at a time and press enter.
> PORT=8089; for PID in /proc/*; do pfiles ${PID} |grep “port: ${PORT}” && echo ${PID}; done
> PORT=9997; for PID in /proc/*; do pfiles ${PID} |grep “port: ${PORT}” && echo ${PID}; done

a) If the commands above return anything (and they shouldn’t), you need to kill the process.
> pfiles process_id (from the output of the commands above to get process details)
> pkill process_id

8) Move the package to your host. Based on your CPU type (SPARC or x64) and the installation method you chose (pkg or tar), copy the Universal Forwarder to your server using scp, Filezilla, WinSCP or your preferred file transfer method.

If installing with tar:
> cp splunkforwarder-8.2.3-cd0848707637-SunOS-x86_64.tar.Z /opt/
> cd /opt
> uncompress splunkforwarder-8.2.3-cd0848707637-SunOS-x86_64.tar.Z
> tar xvf splunkforwarder-8.2.3-cd0848707637-SunOS-x86_64.tar
> chown -R root:root splunkforwarder

If installing with pkg:
> cp splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p /opt/
> cd /opt/
> pkg list -g file:////opt/splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p
> pkgrepo info -s /opt/splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p
> pkg set-publisher -p /opt/splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p splunk
> pkg install -nv splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p
> pkg install -g ./splunkforwarder-8.2.3-cd0848707637-solaris-intel.p5p splunkforwarder

a) For both pkgadd and tar, start and accept the license.
> /opt/splunkforwarder/bin/splunk start –accept-license –answer-yes

This appears to be your first time running this version of Splunk.

Splunk software must create an administrator account during startup. Otherwise, you cannot log in.
Create credentials for the administrator account.
Characters do not appear on the screen when you type in credentials.

Please enter an administrator username: splunkadm  (<– you can use any account name you want here, its for splunkd, not an OS account)
Password must contain at least:
* 8 total printable ASCII character(s).
Please enter a new password:
Please confirm new password:

b) For both pkgadd and tar, enable auto-start when the server is rebooted.
> /opt/splunkforwarder/bin/splunk enable boot-start

c) For both pkgadd and tar, copy the deploymentclient.conf file (provided by the Splunk team) to the path listed below. Note that if a Deployment server is not being used, skip this step.
> cp deploymentclient.conf /opt/splunkforwarder/etc/system/local/
> /opt/splunkforwarder/etc/system/local/
> chown root:root deploymentclient.conf

8) Restart the Forwarder, verify that its running and contact your Splunk team via email. Send them your index, hostname, ip and platform so they can associate your new Forwarder with the proper inputs.
> /opt/splunkforwarder/bin/splunk restart
> /opt/splunkforwarder/bin/splunk status
> ps aevx | grep splunkd

9) Connectivity issues? See if the Solaris firewall is on and has any rules for Splunk ports 8089 and 9997. Adjust rules as needed.
> svcs -x firewall:default
> pfbash pfctl -s rules