riemann.io

What It Is

Riemann is a network monitoring and event aggregation system for distributed systems. It receives events actively pushed by servers and applications, then uses a stream processing language to filter, aggregate, alert on, and forward them. Compared with traditional monitoring based on scheduled polling, the page emphasizes that Riemann can make events visible at millisecond-level latency, helping teams detect failures and verify fixes faster.

Core Capabilities

At its core are “stream primitives”: events are structured data with fields such as host and service, while a stream is essentially a function that receives events. Users can use built-in streams to filter, modify, and combine events, or write their own logic. The configuration itself is a Clojure program, giving it strong expressive power and making it suitable for orchestrating complex rules around anomalies, latency, state changes, cluster statistics, and more in production environments. Riemann also provides a state query language, with query results usable for client-side monitoring, reports, or real-time dashboards.

Languages, APIs, and Ecosystem

Riemann uses Protocol Buffers over TCP/UDP as a compact, portable communication protocol. The page shows examples of a Ruby client sending events and querying state, and includes documentation entries for the Clojure API, Clients, and more. For integrations, it can forward event streams to Graphite, includes built-in Librato Metrics integration, supports email alerts, and can be combined with PagerDuty for SMS or phone-call alerts. For dashboards, the page mentions a small extensible Sinatra app and real-time WebSocket-based dashboards.

Pricing and Deployment

The main page does not mention any commercial subscription or paid plan. It provides a download for Riemann 0.3.11 and highlights open-source contributors, so its primary model appears to be open-source self-hosting. It is best suited to teams willing to deploy, maintain, and write monitoring rules themselves, rather than users looking for an out-of-the-box SaaS product.

Pros, Cons, and Best Fit

Its strengths are low latency, configuration as code, strong extensibility, and the ability to handle complex event processing. The page also claims that ordinary x86 hardware can achieve very high throughput under the default configuration. The downsides are that Clojure-based configuration has a learning curve, and the main text does not show many capabilities common in modern observability platforms, such as logs, tracing, cloud hosting, access control, or SLA guarantees. It is better suited to operations, SRE, platform engineering, and backend teams building custom monitoring and alerting pipelines.

Access from China

No information was found about access from mainland China, mirrors, payments, or local support, so availability is marked as unknown. If alternatives are needed, consider Prometheus, Grafana, Graphite, Zabbix, Nagios, or commercial platforms such as Datadog and New Relic.