Checkmk

Checkmk monitors infrastructure and applications across physical, virtual, containerized and cloud environments. It is designed for scalability, flexibility and low resource consumption, which matters once a single server has to watch thousands of hosts without becoming the heaviest thing on the network.

Checkmk Community is the free and open source edition under the GNU GPL v2. It carries the monitoring core, a web-based interface, agent-based and agentless monitoring, and hundreds of official and community-maintained plugins, which fits smaller environments with modest automation, dashboarding and support requirements.

The commercial editions extend that base in specific directions.

• Pro: distributed monitoring, built-in dashboards, automated agent management and enterprise integrations such as LDAP and REST APIs.
• Ultimate: everything in Pro plus Kubernetes, AWS, Azure and GCP coverage, application metrics over OpenTelemetry, push agents and host auto-registration.
• Cloud: the SaaS version, with automatic updates, backups and no infrastructure to run yourself.
• Multi-tenancy: an Ultimate variant for managed service providers, adding centralized monitoring of many customer environments, isolated access controls and MSP reporting.
• Free trials: evaluation downloads of the paid editions, so nobody has to buy blind.

Installation uses DEB and RPM packages on RedHat and its derivatives, Ubuntu and SUSE Linux Enterprise Server, generally the stable or long-term releases. Every edition also runs as a Docker container, and Pro and Ultimate ship as virtual or physical appliances. Building your own packages is possible, though the prebuilt ones are what the project recommends.