OpenFaaS is a serverless platform that provides an API gateway for deploying, managing, and invoking functions. The gateway handles HTTP routing to functions, collects and exposes Prometheus metrics, implements autoscaling based on invocation rates, includes a built-in AngularJS UI for function management, and supports alerting via integrations like Slack. It uses a plugin architecture for function providers (e.g., Kubernetes, Docker Swarm) via the faas-provider interface, allowing the core to remain decoupled from the underlying runtime. The system processes synchronous function invocations through a reverse proxy and asynchronous invocations via NATS queues.
Kubenurse is a Kubernetes DaemonSet that monitors network connectivity within a cluster by performing periodic checks on API server access (direct and DNS), service/ingress reachability, and inter-node communication. It exports detailed Prometheus metrics including request duration histograms, error counters, and a neighbourhood incoming checks gauge. The architecture uses a controller-runtime client for Kubernetes API discovery, implements an efficient O(N) neighbourhood filtering algorithm based on SHA256 hashing to avoid quadratic scaling, and leverages Go's httptrace package for granular connection metrics. The application features graceful shutdown, TLS support, readiness probes that respect node schedulability, and extensive configuration via environment variables or Helm values.