Open Source SolarWinds Alternatives

Network diagrams drawn by hand go stale the week they are saved, and infrastructure as code state misses drift and anything provisioned outside the pipeline. Scanopy replaces both with a continuously maintained model of what is actually running, produced by a daemon that scans on a schedule.

Every scan yields four views of the same infrastructure: layer 2 physical topology, layer 3 logical subnets, workloads from bare metal through hypervisors to containers, and applications with their service dependencies. Results export as SVG, Mermaid or Confluence pages, embed as live maps, or feed an existing source of truth.

Discovery runs without an agent on every device.

• Automatic discovery: one scanner maps hosts and services across the network.
• Service definitions: more than 230 signatures detect databases, web servers, containers, network gear and enterprise applications.
• Distributed scanning: daemons deployed per segment cover multi-site and multi-VLAN topologies.
• Docker and SNMP: native discovery for containerized services and network hardware, drawing on LLDP and ARP data too.
• Multi-user access: organization management, role-based access and shareable live views for teammates or outside stakeholders.

Self-hosting starts from a Docker Compose file, with a Proxmox helper script and an Unraid community app as alternatives, and the interface answers on port 60072 once the first discovery finishes. The self-hosted build is AGPL-3.0, a commercial license exists for those who cannot meet its terms, and a hosted subscription covers anyone who would rather not run it. Platform teams, network engineers and home labs are the stated audience.

Zabbix watches the availability and performance of an entire IT estate from one place, from a single standalone application up to a large environment spread across data centers. It replaces the pile of per-device checks and ad hoc scripts that accumulate around infrastructure over time.

Metrics arrive with or without an agent, from devices, sensors, operating systems, virtualization and container platforms such as Docker and Kubernetes, cloud infrastructures, databases, web pages, Java ecosystems, API endpoints and business applications. Ready-made templates cover integrations from a low-level device up to a SaaS service.

The rest of the platform turns those metrics into action.

• Resource discovery: find network entities and server resources, then onboard or offboard devices.
• Root cause analysis: detect problems in real time and correlate existing ones with incoming ones.
• Alerts and notifications: reach people through Slack, Jira, Microsoft Teams, email or text messages.
• Visualization: read collected data in graphs, lists, geomaps and network topology maps.
• Multitenancy: run one instance for several data centers, departments or organizations.

Remote locations behind firewalls are covered with remote command execution, and built-in functions handle reporting, auditing, security and service SLA calculations, with metrics and events streamed over HTTP. Zabbix is distributed under AGPL-3.0-only, with downloads and an installation manual published for self-hosted deployment.

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.

Icinga 2 watches whether the machines and services on a network are actually up, tells the right people when they are not, and records performance data that reporting can be built on. It is aimed at environments too large or too scattered for a single check host to cover.

Icinga 2 is the monitoring server, and a working stack pairs it with Icinga Web 2 for the interface. Configuration is plain text written in the Icinga DSL, or managed through the Icinga Director or a configuration management tool. Distributed setups spread checks across multiple locations, so a data center and private, public or hybrid clouds are watched from one system.

The documentation covers the pieces an operator assembles around the server.

• Packages: builds for Debian, Ubuntu, Raspberry Pi OS, Fedora, RHEL, OpenSUSE, SLES, Amazon Linux, Windows and containers.
• Agent based monitoring: run checks on the monitored host itself rather than only from the server.
• REST API: query state and drive the running configuration programmatically.
• Template library: reuse the bundled check command definitions instead of writing each one.
• Modules: extend the stack with the many add-ons and integrations built around Icinga.

Licensing changed at version 2.16.0, where new releases moved to GPLv3 or later while every earlier version and existing source file stays GPLv2 or later, with an OpenSSL linking exception that matters only for OpenSSL 1.x. Community channels handle questions, Icinga partners sell professional support, and the upgrading chapter is worth reading before any major version jump.

Nagios Core watches hosts, services, and networks, telling you when something breaks and again when it recovers. It has done that since 1999, written in C under version 2 of the GNU General Public License, which is a large part of why so much monitoring tooling still speaks its plugin format.

Checks are external programs. The core schedules them, reads their exit status, and acts on the result, so a new kind of check means writing a small program rather than extending the daemon. Hosts form a hierarchy through parent relationships, which lets the software distinguish a host that is down from one merely unreachable behind a failed router. CGI programs bundled with the release provide the optional web interface.

The functionality has held the same shape for a long time.

• Service checks: network services monitored over SMTP, POP3, HTTP, PING, and more.
• Host resources: processor load, disk usage, and similar local measurements.
• Plugin interface: user-developed monitoring methods plug in without touching the core.
• Parent hosts: a hierarchy that separates down from unreachable.
• Notifications: alerts on problem and recovery by email, pager, or a method you define.
• Event handlers: commands run automatically to attempt resolution before a person is paged.
• Web interface: current status, notification and problem history, and log files in a browser.

Log files rotate and archive on their own. Quickstart guides, a user guide, and a documentation library are published alongside the releases, support runs through community forums, and security issues go to a dedicated address, not the public tracker.