Checkmk as an alternative to Nagios

Checkmk gives you the automation, scale and central configuration that Nagios was never designed for, while keeping the plug-ins and checks you already run. Nagios was once an important standard solution for IT monitoring – however, the IT world has changed a lot over the years. Nagios no longer meets the requirements of modern IT monitoring: configuring individual systems is complex, scaling is difficult and the learning curve is steep.

Checkmk makes the switch straightforward and brings advantages Nagios can't match:

• Checkmk installs in minutes, on your own servers or in a Docker container, with no additional database or web server required.
• Checkmk takes over your Nagios hosts through bulk import or a script, and runs your existing Nagios plug-ins
• In Checkmk, you configure the whole environment centrally through the web interface, with no command line needed.
• Checkmk's Agent Bakery manages and updates monitoring agents centrally.
• Checkmk scales across hundreds of sites and 100,000+ hosts, all managed from a single central site.
• Checkmk monitors cloud-native, container and on-premises infrastructure in one platform, and takes in application metrics via OpenTelemetry.
• Checkmk integrates with ServiceNow, Jira, Slack and other enterprise applications.

Checkmk gives you one web interface that brings dashboards, views and configuration together, with a global search that finds any setting and guided workflows for tasks such as adding a host or rolling out agents. When you add a host, auto-discovery lists the services it finds and suggests thresholds for them, and you accept the list as it is or pick only what you need. Rules let you configure something once and apply it to many hosts at the same time, so you no longer maintain a config file per host.

To automate the rest, the Agent Bakery builds agent packages for groups of hosts and keeps them updated automatically after the first installation. The REST API lets you script setup from your own tools, and dynamic host management creates hosts automatically, for example for cloud and container workloads that come and go.

Checkmk’s Micro Core is built for large environments and runs in Pro, Ultimate and Cloud. With distributed monitoring in Pro and Ultimate, you manage hundreds of sites around the world from one central site, so you don’t have to maintain and synchronize separate instances. This is how Pro and Ultimate scale to 100,000+ hosts. For small or segmented remote locations, the lightweight Checkmk Relay in Ultimate and Cloud connects them to the central site over an outbound connection, without needing a full remote site.

Each site stays lean. The agents are lightweight and run even on small servers, and the Micro Core handles thousands of services on a single server. As a guideline, a server with 8 cores at 3.0 GHz, 48 GB RAM and a 480 GB SSD handles around 5,000 hosts and 100,000 to 150,000 services.

Broad coverage keeps the setup simple: with 2,000+ built-in integrations, Checkmk supports devices from a wide range of manufacturers out of the box.