Alertmanager
The deduplication, grouping, and routing layer for Prometheus alerts. Sends to PagerDuty, Slack, email, webhooks.
Tools
Apache SkyWalking
Apache APM platform for service topology, distributed tracing, metrics, logs, and cloud-native diagnostics.
Checkmk Raw
Nagios-descended infrastructure monitoring with auto-discovery, pre-built service checks, and a polished web UI. Raw edition is GPL-2.0.
Coroot
eBPF-based APM for Kubernetes. Zero-instrumentation service maps and SLO dashboards.
Fluent Bit
CNCF graduated lightweight log/metric forwarder. The default in-cluster log shipper for Kubernetes.
Gatus
YAML-configured uptime monitoring with rich assertion DSL. Git-ops friendly.
GlitchTip
Sentry-API-compatible error tracking, but MIT-licensed and lighter. Drop-in for Sentry SDKs.
GoAccess
Fast terminal and HTML dashboard for analyzing web server access logs in real time.
Grafana
The de-facto open-source dashboard layer. Plug into Prometheus, Loki, Tempo, InfluxDB — one pane of glass.
Grafana Loki
Log aggregation inspired by Prometheus: index only labels, not full text. Cheap at scale.
Grafana Mimir
Grafana Labs' horizontally scalable, multi-tenant Prometheus-compatible long-term metrics store.
Grafana OnCall
Open-source on-call and incident-response — schedules, escalation policies, ChatOps. The closest OSS analog to PagerDuty.
Grafana Pyroscope
Continuous profiling (CPU, memory, goroutines). Now part of the Grafana stack.
Grafana Tempo
High-scale distributed tracing backend. Stores traces in cheap object storage (S3, GCS).
Graylog
Mature log management and search with streams, pipelines, dashboards, and alerting. A practical Splunk alternative for log-heavy teams.
Healthchecks
Cron-job and heartbeat monitoring for scheduled tasks. It alerts when an expected ping does not arrive.
HyperDX
Open-source Datadog alternative that correlates logs, metrics, traces, and session replays in one UI.
Jaeger
The CNCF graduated distributed tracing system, originally from Uber. The default open-source choice for traces.
Karma
Drop-in dashboard for Alertmanager — multi-cluster aggregation, richer grouping UI, on-call status, silence management.
Netdata
Real-time per-second metrics with instant auto-discovery. Dashboards out-of-box, zero config.
OpenObserve
Rust-based, columnar, object-storage-backed. Claims 140x lower storage cost than Elasticsearch for logs.
OpenSearch Dashboards
Apache-2.0 fork of Kibana, paired with OpenSearch. The de-facto self-hosted alternative to Elastic for logs visualization.
OpenTelemetry Collector
Vendor-neutral telemetry collector for receiving, processing, and exporting traces, metrics, and logs.
Parseable
Rust-based log lake that writes Parquet to S3-compatible object storage. Compute-storage separated, indexless by design.
Perses
CNCF dashboarding tool with dashboards-as-code, static validation, and Kubernetes-native workflows. A GitOps-friendly Grafana alternative.
Prometheus
The CNCF-graduated, pull-based metrics store. Industry default for self-hosted metrics.
Quickwit
Rust search engine for logs and traces with sub-second queries directly against S3-compatible object storage.
Robusta
Kubernetes-native observability that turns Prometheus alerts into actionable, context-enriched events with auto-remediation playbooks.
Sentry (Self-Hosted)
The upstream product itself — Sentry offers an official self-hosted docker-compose install under FSL license.
SigNoz
Full-stack, OpenTelemetry-native APM + logs + metrics. The closest single-tool Datadog alternative.
Thanos
CNCF-graduated long-term storage and global query layer for Prometheus, backed by object storage.
Uptime Kuma
Self-hosted uptime monitor + status page. The UptimeRobot replacement most engineers land on.
Uptrace
OpenTelemetry APM backed by ClickHouse. Lean alternative to SigNoz.
Vector
High-performance observability data pipeline. Sources, transforms, sinks — written in Rust by Datadog (open source).
VictoriaMetrics
Prometheus-compatible TSDB optimized for ingestion rate and storage cost. Single-binary by default, cluster mode for scale.
Zabbix
Classic agent-based monitoring suite for hosts, networks, and services. Pre-Prometheus old guard, still actively developed.
Zipkin
The original open-source distributed tracing system, born at Twitter in 2012. Single-binary simplicity, still maintained.