Open-source SolarWinds Observability alternatives

Zabbix is an enterprise-oriented open-source monitoring solution for tracking the performance and availability of network devices, servers, virtual machines, applications and cloud services. It scales from a single standalone application up to large distributed environments.

Its feature set covers resource discovery that finds network entities and onboards or offboards devices, metric collection through agents or agentless methods from devices, sensors, operating systems and virtualization platforms, and ready-made templates for monitoring everything from low-level hardware to SaaS services. It also provides alerting on collected metrics and visualization of the data, and it is used for both network and application monitoring.

Zabbix is licensed under AGPL-3.0 and is typically self-hosted on your own servers, backed by a database. The vendor sells commercial support and services around the free software, which suits IT operations teams that want a single monitoring system for mixed infrastructure.

LibreNMS is a network monitoring system that automatically discovers devices and tracks them over SNMP. It is built with PHP and MySQL and supports many kinds of network gear and operating systems, such as Cisco, Linux, FreeBSD, Juniper, Brocade, Foundry and HP equipment. Administrators use it to keep an eye on routers, switches, servers and other networked equipment.

The project describes itself as a community effort that welcomes contributions, puts users' needs first and aims to be friendly, using the Debian Social Contract as the basis of its priorities. The code is a Laravel application, with RRD-based graphing mentioned in the repository topics, and extensive documentation is published on the project site.

The tagline calls it a GPL-licensed system, although GitHub reports the license as 'Other'. LibreNMS is installed on your own server, and there is no hosted version provided by the project. It suits network administrators, ISPs and IT teams that want a free alternative to commercial network monitoring suites.

Checkmk is a comprehensive IT monitoring system designed for scalability, flexibility, and low resource consumption. It monitors infrastructure and applications across physical servers, virtual machines, containers, and cloud environments. It is written mainly in Python.

The Checkmk Community edition is free and open source under the GNU GPL v2. It includes the core monitoring engine, a web-based interface, agent-based and agentless monitoring, and support for hundreds of official and community plugins, and is suited to smaller environments with basic automation, dashboarding, and support needs. Commercial editions extend it: Pro adds distributed monitoring, built-in dashboards, automated agent management, enterprise integrations such as LDAP and REST APIs, and professional support, and Ultimate adds enhanced monitoring for dynamic cloud-native environments such as Kubernetes, AWS, Azure, and GCP.

The website provides documentation, releases, and discussion forums, and a demo of the Pro edition can be downloaded for evaluation. Checkmk suits IT operations teams and managed service providers that want a single tool for servers, networks, and applications.

Icinga 2 is the core of the Icinga monitoring platform. It checks the availability of network resources, notifies users of outages, and generates performance data for reporting. It is built to scale and can monitor large, complex environments spanning multiple locations. The code is written in C++ and released under the GPL-3.0 license as stated in the input.

Configuration can be managed with the Icinga Director, with configuration management tools, or as plain text in the Icinga DSL, a powerful configuration language. The server offers a REST API, TLS-secured distributed monitoring with clustering, and integrations with metrics and logging backends such as Elastic, Graylog, InfluxDB, Graphite, and OpenTSDB. Icinga Web 2 is required on top for the web interface.

The README links to installation, monitoring basics, configuration, and distributed monitoring documentation. Icinga suits system administrators and operations teams who need a mature, configurable monitoring system for servers, networks, and services, especially those that want infrastructure-as-code style configuration.

Cacti is an open-source network monitoring and graphing platform built on RRDtool. It provides a scalable framework for collecting, storing and visualizing time-series data from network devices, servers and applications. It is a PHP application, licensed under GPL-2.0, that is typically installed on a web server alongside MariaDB or MySQL.

Core capabilities listed in the README include automated device discovery, local and remote data collection, templating for graphs, data sources and round-robin archives, SNMP polling across versions 1, 2 and 3 with IPv6 support, role-based access control, a plugin framework and dynamic graph viewing and export. Scheduled polling and maintenance scripts run through PHP on the command line or CGI.

The project maintains a stable 1.2.x branch and a develop branch heading toward 1.3.x, with different minimum requirements for MariaDB, MySQL, PHP, RRDtool and Net-SNMP in each. Red Hat family distributions are a common baseline, and Debian and Ubuntu are well supported. Installation from a source checkout is described in the README, with the latest release published on GitHub.

Nagios Core is a monitoring program for hosts, services and networks, written in C and released under the GNU General Public License version 2. It checks whether your systems and services are working and tells you when something goes wrong or recovers.

It can monitor network services such as SMTP, POP3, HTTP and ping, as well as host resources like processor load and disk usage. A plugin interface lets you write your own checks. You can define a host hierarchy with parent hosts, which lets Nagios tell hosts that are down apart from hosts that are only unreachable. Notifications go out by email, pager or a user-defined method, and event handlers allow automatic responses to problems.

Other features include automatic log file rotation and archiving, plus CGI programs that provide an optional web interface for current status, notification history and logs. Documentation, quickstart installation guides, a user guide and support forums are available from the Nagios site. Paid Nagios products exist separately from this open-source core.