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For Ubuntu 24.04, the most directly versioned walkthrough is Nagios Core’s source-build guide, which explicitly covers Ubuntu 22.x and 24.x. Ubuntu also documents a separate apt-based installation route. This guide follows the source-build method and keeps the package route distinct: their installation and update paths are not interchangeable.
Choose an installation route
| Route | What the available documentation establishes | Best fit |
|---|---|---|
| Nagios source build | Nagios provides a step-by-step guide for Ubuntu 22.x and 24.x, including build prerequisites, Core installation, Apache setup, plugin installation, and verification. Nagios Core source-install guide | Administrators who want to build Core from upstream source and follow Nagios’s Ubuntu 24.x instructions. |
| Ubuntu packages | Ubuntu documents an apt-based Nagios Core 4 installation and Apache web-interface configuration. Ubuntu Server: Install Nagios | Administrators who prefer Ubuntu’s package-managed installation path. |
This article uses the source-build route. Do not mix commands or package assumptions between the two methods. The available information does not establish current Noble repository package names, package versions, or a complete command sequence for Nagios’s Ubuntu package repository.
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Check requirements and prepare Ubuntu
Nagios lists Ubuntu 24.04 LTS as a supported distribution and groups Ubuntu 22.x and 24.x together in its source-build instructions. Its published minimum hardware guidance is 2 CPU cores, 2 GB of RAM, and 20 GB of free disk space; it recommends 4 or more cores and 4 GB or more of RAM for larger deployments. These are Nagios-published minimums, not a workload-specific sizing guarantee. Nagios Core and the source-install guide
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The source guide lists build and runtime prerequisites including autoconf, GCC, libc, make, wget, unzip, Apache, PHP, GD development files, UFW, OpenSSL, and libssl development files. Nagios states that “As of Nagios Core 4.4.7, openssl is a required prerequisite.” Nagios Core source-install guide · OpenSSL prerequisite note
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Use the source guide’s Ubuntu 22.x / 24.x prerequisite and command sequence as written for your system. Confirm the package names and current Core and Plugins release download links in that guide before installing; its download behavior tracks the latest release, so this article does not freeze a release number.
Build and install Nagios Core from source
The source route comprises distinct stages. Follow the command blocks in Nagios’s Ubuntu source-install guide for each stage, rather than substituting instructions from an older Ubuntu tutorial.
- Download and extract Core. Obtain the current Core source archive using the guide’s download instructions, then unpack it.
- Configure and compile. Run the documented configure command with the Apache configuration path, then compile the source with the guide’s build command.
- Install Core accounts and components. Create the Nagios users and groups, then install the binaries, daemon initialization files, command mode, sample configuration, and Apache configuration as directed.
- Configure Apache and firewall access. Enable the required Apache modules and allow Apache through UFW using the guide’s commands.
- Create web authentication. Use the guide’s
htpasswdstep to create a login for the web interface, then restart Apache.
Do not rely on the age-sensitive quickstart page for these commands. Nagios identifies that Ubuntu guide as written for Ubuntu 14.04 and tested with Nagios 4.2.1 and Nagios Plugins 2.1.3; its PHP and version examples are legacy. Nagios Ubuntu quickstart
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Install Nagios Plugins
Core needs plugins to run checks. After installing Core and configuring Apache, download the current Nagios Plugins source using the source guide’s instructions, extract it, compile it, and install it. Keep the plugin installation as a separate stage from the Core build; the guide provides separate download and build steps. Nagios Core source-install guide
Validate the web interface and a check
- Open the Nagios web interface using the server address and path specified in the source guide, and sign in with the account created through
htpasswd. - Schedule a check through the interface, following the guide’s verification instructions.
- Confirm that the check runs and that a plugin response appears. If it does not, return to the guide’s configuration and plugin-install stages and verify that the installed files and web configuration match its instructions.
Decide how the web interface will be protected
The documented setup creates Apache basic authentication and describes allowing Apache in UFW. Those steps establish a login and network allowance; they are not, by themselves, a complete production security design. Decide which networks should reach the service and how authentication and authorization should work before exposing it beyond the intended network. Ubuntu’s installation guide points administrators to Apache and Nagios documentation for authentication and authorization. Ubuntu Server: Install Nagios
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Core or XI: which Nagios edition?
| Consideration | Nagios Core | Nagios XI |
|---|---|---|
| Cost | Free | Paid |
| Configuration interface | Text-configured | Web-based GUI with configuration wizards |
| Dashboards and reports | Not listed as XI features for Core on the cited product page | Includes dashboards and reports |
| Support | Professional support is not listed as a Core feature on the cited product page | Professional support is offered |
Nagios Core suits administrators comfortable with text-based configuration who want the free product. Nagios XI is the paid, GUI-led product for users who value setup wizards, dashboards, reports, and professional support. Nagios Core
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