Nagios vs Prometheus – Open Source Monitoring Tool Comparison (Pros and Cons)

Nagios vs Prometheus – Open Source Monitoring Tool Comparison (Pros and Cons). Nowadays, most organizations implement continuous delivery models to frequently deliver and release high-quality software and features. To achieve higher levels of customer or end-user satisfaction and retention, the capability to monitor and manage systems and applications, detect problems early, and resolve those problems is quite important.

Monitoring tools are pretty crucial for production environments. You cannot have a complex production environment without a monitoring tool. They monitor various components like servers, switches, applications, or services. Whenever something goes wrong, they generate an alert and another alert when the problem has been solved.

Continuous monitoring is a process in which key business processes and controls are assessed. This permits ongoing insight into the effectiveness of controls and integrity of the applications running. This can also be considered a process and technology used to detect compliance and risk issues associated with the organization’s financial and operational environment monitoring.

DevOps can involve two different aspects. The first one is application performance monitoring which can help provide code-level visibility to enable quick identification of performance issues and rapid remediation. The second one is server monitoring which operates at the infrastructure level and allows tracking server health in cloud physical and hybrid environments. Continuous monitoring is involved in all the phases of DevOps, be it steering, planning, developing, or testing.

What is Nagios Open Source Monitoring Tool?

Nagios Core monitors the network for problems caused by overloaded data links or network connections and monitors routers, switches, and more. Easily able to monitor the availability, uptime, and response time of every node on the network, Nagios can deliver the results in various visual representations and reports.


Nagios features web interface and advanced dashboarding for visualization that allows users to do capacity planning, snapshot configurations , that saves  and reuses data  in your infrastructure management.

Prometheus Open Source Monitoring Tool

Prometheus is an open-source system monitoring and alerting toolkit originally built at SoundCloud. Prometheus collects and stores its metrics as time-series data, i.e., metrics information is stored with the timestamp at which it was recorded, alongside optional key-value pairs called labels.

Nagios vs Prometheus Open Source Monitoring Tools Comparison

Nagios vs Prometheus Open Source Monitoring Tools Features

Both Nagios and Prometheus come with their own set of features.

Nagios server features

Following are some of the features of Nagios:

  • Comprehensive Server Monitoring: Unlike Prometheus, Nagios provides server, network, and application monitoring via powerful API’s.
  • Spot problems before they occur
  • Nagios is customizable and has a flexible monitoring system.
  • Infrastructure: Nagios legacy infrastructure is more focused on networking and servers. While Prometheus monitors the applications running in Kubernetes.

Prometheus server features

Following are some of the features of Prometheus:

  • Time-based Monitoring: It helps in monitoring and managing the applications according to the schedule and triggers them in accordance with the provided timeline.
  • OS Compatibility: Prometheus is compatible with every Operating System, unlike Nagios that is only compatible with Windows and Linux.
  • Cheap: Its basic version is free. Also, the enterprise version costs around ten times less as compared to Nagios.
  • Other Features: After alerts, Prometheus also allows grouping, rerouting, and duplication which are not available in Nagios.
  • Non dependent on distributed storage

Maintenance comparison

Prometheus is easier to deploy as compared to Nagios. It has a Docker image that can work on every type of machine. Moreover, you only need to manage the storage and exporters’ deployment for maintenance. However, Nagios has a downloadable bundle with relevant packages for different products with Windows and Linux distributions. You need to configure the settings after downloading and installing Nagios.

Checking Methods Nagios vs Prometheus

In Prometheus, when you need to monitor or check logs in the application, you need to use the query language. On the other hand, in Nagios, to perform a check, some services or scripts provided with the help of the host are used.

Monitoring comparison

Usually, basic monitoring like looking for a small or a static system is performed on Nagios. In addition, Nagios is also used to make logs of the details of issues faced by the system. On the flip side, as Prometheus’s servers are based on Kubernetes, it is suitable for cloud-based or virtual environments. Moreover, Prometheus is also used for whitebox monitoring.

With whitebox monitoring, you can inspect the system’s insides by instrumenting the host operating system or application code to collect the specific metrics you are looking for. You know how the system works, and you can use that knowledge to pick the things you want to keep tabs on. Whitebox monitoring can give an IT support specialist or system administrator insight into the different parts of a technology stack. This provides detailed information for debugging, impending problems, or immediate issues.


While using Prometheus, you cannot know the problems earlier. But to solve the known issues, it uses alerts and schedules them in an organized manner. Contrastingly, in Nagios, the issues are known prior, and to solve them, the user is notified even before they arise.


Although the setup process of the Prometheus application is simple and provides easy monitoring, it does not offer customizability or plugins. But to extend Prometheus, you can use queries. Conversely, Nagios monitoring system provides customizability and flexibility. Therefore, users generally use Nagios for its easy monitoring and flexibility. Furthermore, Nagios has free visualization plugins, which is why customers prefer it over other monitoring tools.


Nagios provides free checks and plugins, but one issue is that it does not integrate other applications. Contrarily, Prometheus allows integration with other systems, which opens the door for other possibilities.

User Interface

Unfortunately, the user interface of Prometheus is not good enough; it just displays the metrics. Moreover, configuring the settings of Prometheus is also tricky. As it does not work with passive agents, few active agents are available. Furthermore, generally, multiple applications and systems are used with Prometheus.

In the case of Nagios, the user interface is interactive, which also helps in configuring different settings. But as any particular programming language is not used to code Nagios, sometimes debugging becomes very difficult.


As Prometheus is an open-source project it has a very rich community. There are a lot of contributors that continuously try to update it according to the requirements and other apps. Moreover, Prometheus has a monitoring community on GitHub. On the other hand, Nagios Core comparatively has a very small community. As there are very few contributors, Nagios does not get updated regularly.

Nagios vs Prometheus Open Source Monitoring Tools Comparison

After discussing the differences above, it is clear that Prometheus and Nagios have different use cases. Both of them offer a distinct set of features. Nagios is a tool for continuous monitoring of systems, applications, services, and business processes, etc in a DevOps culture. In the event of failure, Nagios can alert technical staff of the problem, allowing them to begin remediation processes before outages affect business processes, end-users, or customers.

While Prometheus is software for monitoring and alerting, it is open-source and is used for time-series data. Therefore, it can analyze time-series data to identify and create real-time alerts. Another fundamental idea of this monitoring software is that it is installed locally in each node, making it independent and reliable because it is not centralized. Currently, it is used a lot for container platforms like Docker, OpenShift, etc, because it is scalable, independent, reliable, and can analyze this time-series data.

Hopefully, this article helps you figure out your requirements and make an informed decision. An interesting thing to note is that some companies use Nagios and Prometheus alongside each other as they offer solutions to different problems. Both solutions are helpful for DevOps as they provide real-time app status monitoring and enable the teams to stay ready in advance in case of failure.

Avatar for Emad Bin Abid
Emad Bin Abid

I'm a software engineer who has a bright vision and a strong interest in designing and engineering software solutions. I readily understand that in today's agile world the development process has to be rapid, reusable, and scalable; hence it is extremely important to develop solutions that are well-designed and embody a well-thought-of architecture as the baseline. Apart from designing and developing business solutions, I'm a content writer who loves to document technical learnings and experiences so that peers in the same industry can also benefit from them.

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