Nagios Opplæring: Hva er Nagios Verktøy? Architeknikk og installasjon

Nagios is one of the most widely used open-source tools for the continuous monitoring of IT infrastructure. This tutorial explains what Nagios is, how its client-server architecture and plugins work, how to install it on AWS, and where it fits within a modern DevOps arbeidsflyt.

Hva er kontinuerlig overvåking?

Continuous monitoring is the practice of detecting, reporting, and responding to every issue or attack that occurs across an infrastructure. Once an application is deployed to a server, continuous monitoring takes over the job of watching the company’s systems and responding appropriately. It complements continuous integration tools such as Jenkins by extending automated oversight into production.

Hva er Nagios?

Nagios is open-source software for the continuous monitoring of systems, networks, and infrastructures. It runs plugins that are stored on a server and connected to a host or another server on your network or the Internet. Whenever a failure occurs, Nagios raises an alert so that the technical team can begin the recovery process immediately.

Because it watches systems, applications, services, and business processes around the clock, Nagios is a popular choice for continuous monitoring within a DevOps culture.

Hvorfor trenger vi Nagios?

Here are the important reasons to use the Nagios overvåkingsverktøy:

• Detects all types of network and server issues.
• Helps you find the root cause of a problem so you can apply a permanent solution.
• Actively monitors your entire infrastructure and business processes.
• Lets you monitor and troubleshoot server performance issues.
• Helps you plan infrastructure upgrades before outdated systems create failures.
• Helps you maintain the security and availability of your services.
• Can automatically fix problems in critical situations.

Historie Nagios

1996 – Ethan Galstad creates a simple MS-DOS application that “pings” Novell NetWare servers and sends numeric pages. The basic architectural concept later used for Nagios er født.

1998 – Ethan uses the ideas and architecture of his earlier work to begin building a new application that runs on Linux OS.

1999 – The project is released as open source under the name “NetSaint.” The plugins originally distributed as part of the NetSaint distribution are soon split into a separate Nagios Plugins project.

2002 – Ethan renames the project to “Nagios" på grunn av varemerkeproblemer med navnet "NetSaint."

2005 - Nagios blir SourceForge.net Project of the Month in June.

2007 – Ethan founds Nagios Enterprises, LLC to provide consulting and development services around Nagios.

2009 - Nagios Enterprises slipper sin første kommersielle versjon, Nagios XI. The open-source project is renamed Nagios Kjerne.

2010 - Nagios Fusion is released as a central dashboard for multiple monitoring servers.

2013 - Nagios Core 4 is released, along with Nagios Network Analyzer and the NCPA cross-platform agent.

2014 - Nagios Log Server is released for enterprise log monitoring and management.

2015 - Nagios XI 5 arrives with over 200 enhancements and improvements.

2016 - Nagios Core surpasses 7,500,000 downloads directly from the SourceForge.net website.

2017 - Nagios Log Server 2 is released, and Nagios crosses 1,200 software downloads per day.

2019 – Ethan Galstad steps down as CEO of Nagios Enterprises and hires a successor.

2022 – Ethan Galstad resumes his position as CEO.

2023 – The 2024R1 versions of Nagios XI, Log Server, Network Analyzer, and Fusion are released with major updates to each product.

2024 - Nagios Enterprises celebrates its 25th anniversary and Nagios XI its 15th. Nagios Core surpasses 8,500,000 SourceForge.net downloads, the Nagios Library site is relaunched, and the first version of the Nagios Core Services Platform (CSP) ships to the community.

2025 – The sixth Nagios World Conference is held at company headquarters in St. Paul, MN. Nagios reports more than 10,000 customers and grows to 100 employees. Nagios Log Server 2026 ships with a new Simple Search homepage and an upgrade to OpenSearch 3.1.0.

2026 - Nagios Core 4.5.x continues with maintenance and security releases (4.5.11 in January, 4.5.13 in May), while Nagios XI moves to the 2026R1 series with new configuration wizards for Red Hat OpenShift. Nagios World Conference 2026 is scheduled for September 14–17 in St. Paul, MN.

Funksjoner av Nagios

The following are the important features of the Nagios overvåkingsverktøy:

• Relatively scalable, manageable, and secure.
• Provides a good log and database system.
• Offers informative and attractive web interfaces.
• Automatically sends alerts when a condition changes.
• Skips redundant checks when services are already running fine.
• Helps you detect network errors and server crashes.
• Lets you troubleshoot server performance issues.
• Fixes issues automatically as they are identified during monitoring.
• Monitors your entire business process and IT infrastructure in a single pass.
• Uses an architecture that makes it easy to write new plugins in the language of your choice.
• Reads its configuration from an entire directory, helping you decide how to define individual files.
• Uses topology to determine host dependencies.
• Monitors network services such as HTTP, SMTP, SNMP, FTP, SSH, and POP.
• Helps you define a network host hierarchy using parent hosts.
• Lets you define event handlers that run during service or host events for proactive problem resolution.
• Supports the implementation of redundant monitoring hosts.

Nagios Architecture

Nagios uses a client-server architecture. On a typical network, the Nagios server runs on a host, while plugins run on all the remote hosts that need to be monitored.

1. The scheduler is a component of the server part of Nagios. It sends a signal to execute the plugins on the remote host.
2. The plugin gets the status from the remote host.
3. The plugin sends the data back to the process scheduler.
4. The process scheduler updates the GUI, and notifications are sent to administrators.

plugins

Nagios plugins provide the low-level intelligence that tells Nagios Core how to monitor almost anything. A plugin acts as a standalone application, but it is designed to be executed by Nagios Kjerne. Den kobles til Apache, which is controlled by CGI to display the result, while a connected database keeps the log files.

Hvordan fungerer plugins?

Consider the example above:

• Check_nt is a plugin used to monitor a Windows machine, and it is usually available on the monitoring server.
• NSClient++ should be installed on every Windows machine that you want to monitor.
• An SSL connection between the server and the host continuously exchanges information between them.

Similarly, the NRPE (Nagios Remote Plugin Executor) and NSCA plugins are used to monitor Linux and Mac OS X hosts respectively.

GUI

Ocuco Nagios interface displays web pages generated by CGI. It can show status through colored buttons (green or red), sounds, graphs, and more.

When a soft alert is raised repeatedly, it becomes a hard alert, and the Nagios server then sends a notification to the administrator.

Slik installerer Nagios Verktøy hos AWS

Trinn 1) Abonnere på Nagios.
Gå til Nagios listing on AWS Marketplace and click Continue to Subscribe.

Trinn 2) Read the terms and conditions, then accept them.

Trinn 3) View the message. You will see a subscription-pending message.

Trinn 4) Do the configuration. Refresh the page after a few minutes and click Continue to Configuration.

Trinn 5) Start Nagios. Keep the default settings and click Continue to Launch.

Trinn 6) Review the settings, create a new key, and click Launch.

Trinn 7) Note the public DNS of your instance.

Trinn 8) Convert the pem file to ppk. On your Windows machine, use the PuTTY generator to convert the pem file to a ppk file.

Trinn 9) In PuTTY, enter the public DNS.

Trinn 10) In the Auth section, enter the ppk key and click Open.

Trinn 11) In the terminal, enter the login name as ubuntu and run the command.

1. Kjør denne kommandoen: sudo htpasswd -c /etc/nagios3/htpasswd.users nagiosadmin
2. Enter a new password of your choice.

Trinn 12) Open your browser and go to http://<Public DNS>/nagios3 (in this example, http://ec2-54-209-48-136.compute-1.amazonaws.com/nagios3/).

Skriv inn brukernavn: nagiosadmin

Password: the one set in the previous step.

Trinn 13) Ocuco Nagios installation is done, and Nagios laster.

Bruk av Nagios

Ocuco Nagios nettverksovervåkingsverktøy is a health-check and monitoring system for a typical data centre, covering all types of equipment, such as:

• Servers and network nodes.
• Application monitoring from a single console.
• Application monitoring with transaction-level insights.
• Middleware and messaging components.
• Tilpassbare rapporter og dashboards.
• UPS backup systems.
• Bio-metric identification systems.
• Temperature and humidity control systems (sensing mechanisms).
• CCTV and NVR systems.
• Storage subsystems (NAS and SAN).

Ulemper ved å bruke Nagios

• Important features such as wizards and interactive dashboards are only available in Nagios XI, which is a fairly expensive tool.
• Nagios Core has a confusing interface for new users.
• It uses many configuration files that can be hard to set up.
• Nagios cannot monitor network throughput.
• The tool lets you monitor the network but not manage it.
• Nagios makes no distinction between devices such as servers, routers, or switches, because it treats every device as a host.

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