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Heimdall

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Heimdall's own site

What Heimdall is

Heimdall is a free, cross-platform hardware monitoring system with a real-time terminal dashboard. It tracks CPU, memory, disk, network, temperature, GPU, and power across multiple machines. Unprivileged daemons stream metrics over gRPC to a central hub, which serves dashboards; daemons can discover hubs through mDNS and hosts can be tagged for fleet organization. Hubs can relay metrics across sites or networks, persist data to Prometheus-compatible backends such as Prometheus, Thanos, Mimir, and VictoriaMetrics, and expose fleet data in Prometheus/OpenMetrics format for tools such as Grafana. Declarative threshold rules with hysteresis can send webhooks when limits are breached or cleared. The heimdall-cli provides typed JSON commands for hosts, processes, logs, and allow-listed diagnostics from scripts, CI/CD, and agents. Diagnostics are read-only, opt-in per daemon, and audited. Separate hub, dashboard, daemon, and optional helper binaries are provided. Heimdall runs on Windows, macOS, Linux, API, and self-hosted deployments under AGPL-3.0-or-later. Without a configured TSDB, history is held in memory and lost after hub restart.

Who it suits

It suits homelabs, GPU machines, server racks, laptops, and automation workflows that query fleet data from scripts, CI/CD, or agents.

What it does well

  • Monitors broad hardware metrics
  • Supports multi-machine fleet dashboards
  • Prometheus/OpenMetrics and backend compatibility
  • Webhook threshold alerts
  • Read-only audited diagnostics

What to know first

  • History is lost after hub restart without TSDB
  • Default hub is plaintext and unauthenticated
  • Secure deployment requires extra configuration

Verdict

Heimdall provides free fleet monitoring with terminal dashboards, metric backends, alerts, and scriptable diagnostics. Operators should configure persistent storage and the recommended enrollment and TLS protections for networked deployments.

Facts from Heimdall's own pages

Alerts
Declarative threshold rules with hysteresis can send webhooks when thresholds are breached or cleared. · github.com, 9 Oct 2026
Architecture
Unprivileged daemons stream host metrics over gRPC to a central hub, which serves dashboards. · github.com, 9 Oct 2026
Backend compatibility
The hub can persist to and recover from Prometheus-compatible backends including Prometheus, Thanos, Mimir and VictoriaMetrics. · github.com, 9 Oct 2026
CLI
heimdall-cli provides typed JSON commands for querying hosts, processes, logs, and allow-listed diagnostics from scripts, CI/CD, and agents. · github.com, 9 Oct 2026
Command controls
On-demand diagnostics are read-only and allow-listed, are opt-in per daemon, and are audited. · github.com, 9 Oct 2026
Commands
On-demand diagnostics are read-only, allow-listed, opt-in per daemon and audited; privileged commands use the optional root helper. · github.com, 9 Oct 2026
Discovery and federation
Daemons can discover a hub over mDNS, and hubs can relay metrics upstream across sites or networks. · github.com, 9 Oct 2026
Fleet discovery
Daemons can discover a hub over mDNS, and hosts can be tagged to organize a fleet. · github.com, 9 Oct 2026
Installation
The project provides separate hub, dashboard, daemon, and helper binaries, with the helper optional on each host. · github.com, 9 Oct 2026
Integrations
The hub can expose Prometheus/OpenMetrics metrics for scraping by Prometheus and graphing in Grafana. · github.com, 9 Oct 2026
Intended use
The README suggests using Heimdall for homelabs, GPU machines, server racks, or an individual laptop. · github.com, 9 Oct 2026
Intended users
The maker presents Heimdall for homelabs, GPU machines, server racks and laptops, and for scripts, CI/CD and AI agents that query fleet data. · github.com, 9 Oct 2026
License
The repository lists the project under the AGPL-3.0-or-later license. · github.com, 9 Oct 2026
License and support
The project is licensed AGPL-3.0-or-later, and its README welcomes contributions such as metric adapters, platform ports, guides and bug fixes. · github.com, 9 Oct 2026
Limits
Without a configured TSDB, hub history is bounded in memory and is lost when the hub restarts. · github.com, 9 Oct 2026
Logs
Log streaming is opt-in by configuring log source aliases, and the hub caps pushed lines and keeps a bounded ring per host. · github.com, 9 Oct 2026
Metrics
It monitors CPU, memory, disk, network, temperature, GPU, and power across multiple machines. · github.com, 9 Oct 2026
Network model
Daemons send data over an outbound stream and do not listen for inbound connections. · github.com, 9 Oct 2026
Platforms
Prebuilt releases are listed for Linux, macOS, and Windows on amd64 and arm64. · github.com, 9 Oct 2026
Purpose
Heimdall is a lightweight, cross-platform hardware monitoring system with a real-time terminal dashboard. · github.com, 9 Oct 2026
Security
The secure deployment guide recommends requiring an enrollment token and enabling TLS for networked deployments; it says the default hub is plaintext and unauthenticated. · github.com, 9 Oct 2026

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