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You Inherited a Nagios XI System. Now What?

August 18, 2025 -Sometimes system administrators inherit a Nagios XI instance without any information. No handoff, no documentation, and not even a login. So, what do you do in this situation? 

In this article, we will walk through exactly what to do when you’ve (unexpectedly) been handed a Nagios XI instance. By the end, you will not only understand how to manage your new instance but also how to ensure a smoother handoff to the next Nagios Admin. 

Let’s work through the steps:

1. Get Support. 
2. Gain Access to the XI Instance. 
3. Understand the XI Environment. 

Step 1: Get Support 

The first step is to find some help. Luckily, Nagios has several resources to make this easier for you:

Nagios Customer Success Managers (CSMs)

Who they are: CSMs can help with a wide variety of Nagios-related questions—everything from accessing systems to getting connected to the right support teams.

In this situation, CSMs are your first point of contact for support.

What they help with:

• Answering basic support questions.
• Helping you locate resources, such as documentation and video tutorials, for your XI instance.
• Getting you in touch with support teams.
• Renewing or buying a new license.

How to Contact CSMs: Send an email to csm@nagios.com.

Pro Tip: If you’re starting from nothing in your instance, reach out to a CSM first. They can make you the primary contact for the XI account so you can access more resources, including Nagios Support.

Nagios XI Administrator Guide

Looking for technical depth? The Nagios XI Administrator Guide offers detailed documentation for installing, configuring, and managing your XI instance.

Use it to:

• Understand core components and architecture.
• Learn how to customize your monitoring environment.
• Troubleshoot common issues and optimize performance.

Pro Tip: Bookmark this guide—it’s your go-to reference for running and maintaining XI smoothly.

Nagios Library

If you still have questions or want to explore a wider range of resources, the Nagios Library is a great place to look.

The Nagios Library is where you’ll find many tools and resources, including:

• How-to guides and documentation.
• Educational resources and videos. 
• Articles with IT monitoring insights. 

Pro Tip: Not sure where to start? Use the search bar in the Nagios Library to quickly find content related to your question.

Nagios Knowledge Base

The Knowledge Base offers quick, practical answers to common questions, though many resources are now moving to the Nagios Library.

Why it’s helpful:

• Fast, easy-to-search questions.
• Quickly get answers to common issues.

Pro Tip: The Knowledge Base is best for quick “how-to” questions and common issues.

Nagios Support Team

Not able to find your answer in the Nagios Library or Knowledge Base? Ask our Support Team. They can help with:

• Break/fix support.
• Remote troubleshooting sessions (if necessary.)

How to Contact Support: Through the XI interface or through the Nagios Support Forum.

Pro Tip: If you need a remote session, make sure you have an admin account for XI as well as root access to the system XI is running on.

Nagios Support Form

Another valuable resource is the Nagios Support Forum, which is community-driven and free to use. It’s an ideal place to get quick answers to “how-to” questions.

Pro Tip: We recommend checking the Nagios Library and Knowledge Base for answers first. If you still need help, then post your question in the forum.

Step 2: Gain Access to the XI Instance

The next goal is to get access to your Nagios XI environment.

1. Get root access to the server XI is running on.

Pro Tip: If you have physical access to the system, you can typically gain root access to it.

2. Reset the Nagios Admin account password to get access to your XI instance.

Run the script: reset_nagiosadmin_password.php

Finding Help in the XI Interface

Not familiar with getting support within the XI interface? Here is how to navigate:

Step 3: Understand the XI Environment

Once you’re able to access your XI instance, it’s now time to find out what you’re monitoring and how everything’s connected. These next few sections will help you find where the previous Nagios Admin may have put helpful information.

Your First Stop: Network Status Map

Navigate to Home > Maps > Network Status Map

The Network Status Map identifies:

• Parent-child host relationships.
• Devices and the switches they are connected to.
• A visual layout of your network for easier troubleshooting.

Pro Tip: An advantage to setting up parent-child host relationships is that it helps reduce email storms. When a parent host goes down, all of the child hosts are flagged as unreachable. This means you will only receive notifications for the parent host, and you won’t be overwhelmed with unnecessary notifications for every affected child host.

Custom Variables

Nagios Admins will often leave key information about hosts and services within the custom variables. Custom variables are any piece of information that someone finds relevant to a host or service.

Here are a couple examples of helpful custom variables:

• Use the same variables in XI that you use in Ansible. This will help keep monitoring and automation in sync to help you manage your environment more efficiently.
• Include device ID tag numbers in host definitions for quicker reference when contacting manufacturers for support.

These suggestions will help make it a smoother knowledge transfer to the next Nagios Admin.

Pro Tip: XI can act as a dynamic Ansible inventory source, supplying connection info and variables Ansible uses to maintain your environment—making it easy to run updates or tasks.

Final Thoughts

Inheriting an XI instance with no information can seem complicated, but with the right steps and resources, you can take control and optimize your monitoring environment.

Here’s a brief summary:

• Reach out to the CSMs for guidance and help with gaining access.
• Use support resources like the Knowledge Base and Nagios Library to find answers and best practices.
• Secure admin and root access to manage the environment.
• Understand what’s being monitored using tools like the Network Status Map and custom variables.
• Document your own changes to make the transfer easier for the next Nagios Admin.

Nagios XI and all Nagios solutions are available in UK through Simple IT Distribution LTD, Nagios Partner in the UK.

About Simple IT Distribution LTD

Simple IT Distribution LTD is backed by 10 years of experience in Value Added IT Distribution. What sets us apart from the crowd is our customer-centric approach, the quality services (consulting, implementation, training, support), and the people behind them, which are experienced and certified proffessionals. We provide sales and technical advice and deliver the solutions that best meed our customers' diverse technology needs. Our partners are hand-picked from the top vendors, and we back up their solutions with certified professionals, to give you nothing but the best.

For more information, please visit www.simpleit-distribution.co.uk .