> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Cilium Hubble Overview > Cilium Hubble enhances network observability, troubleshooting, and security for Kubernetes clusters through eBPF, offering metrics, UI/CLI tools, and integrations with Prometheus and Grafana. Cilium Hubble extends Cilium’s eBPF datapath to deliver unparalleled network observability, troubleshooting, and security enforcement for Kubernetes clusters. In this guide, we’ll cover Hubble’s architecture, built-in metrics, UI/CLI tools, and how to integrate with Prometheus and Grafana. Hubble components: * **eBPF datapath** on each node for flow and event capture * **Relay** to aggregate data across nodes * **Integrations** with Prometheus (metrics), Grafana (dashboards, service maps), and Hubble UI/CLI for interactive inspection ![The image is a diagram explaining Hubble, a tool built on Cilium (eBPF), highlighting its features like network observation, troubleshooting, and monitoring, with components like Grafana, Prometheus, and Hubble UI/CLI. It shows nodes with pods and integrations for metrics, service maps, and flow inspection.](https://kodekloud.com/kk-media/image/upload/v1752880399/notes-assets/images/Kubernetes-Networking-Deep-Dive-Cilium-Hubble-Overview/hubble-cilium-ebpf-diagram-features.jpg) ## Built-in Metrics for Prometheus Hubble exports metrics in the [Prometheus OpenMetrics format](https://prometheus.io/docs/instrumenting/exposition_formats/), making it simple to monitor network health and trigger alerts on key events: | Metric Category | Tracks | Use Case | | ----------------- | ----------------------------------------------- | ------------------------------------------- | | dns | DNS queries, failures, latencies | Alert on high DNS failure rate | | drop | Packet drops by policy or error | Identify unintended policy blocks | | tcp | TCP connections, retransmissions, resets | Detect connection instability | | flow | Flow counts, throughput, duration | Baseline traffic trends | | port-distribution | Top port usage across services | Spot unexpected open ports | | icmp | ICMP echo requests and replies | Monitor ping flood or unreachable hosts | | httpV2 | HTTP/2 metrics with exemplars and label context | Trace request latencies with context labels | Enable only the metrics you need to reduce data volume and improve query performance. ### Enabling Hubble Metrics via Helm When installing or upgrading Cilium with Helm, you can enable Hubble and Prometheus integration in one step: ```bash theme={null} helm upgrade cilium cilium/cilium --version CILIUM_VERSION \ --namespace kube-system \ --reuse-values \ --set hubble.enabled=true \ --set hubble.relay.enabled=true \ --set hubble.ui.enabled=true \ --set hubble.metrics.enableOpenMetrics=true \ --set prometheus.enabled=true \ --set operator.prometheus.enabled=true \ --set hubble.metrics.enabled="{dns,drop,tcp,flow,port-distribution,icmp,httpV2:exemplar=true;labelsContext=source_ip\,source_namespace\,source_workload\,destination_ip\,destination_namespace\,destination_workload\,traffic_direction}" ``` ## Hubble UI and CLI Hubble offers both a web-based UI and a scriptable CLI, providing deep visibility into service interactions, network flows, and security policy verdicts. ![The image outlines Hubble's offerings, including Built-in Metrics for Prometheus, Hubble UI, and Hubble CLI, each with specific features related to metrics, service dependencies, network flows, protocols, filtering, and security information.](https://kodekloud.com/kk-media/image/upload/v1752880400/notes-assets/images/Kubernetes-Networking-Deep-Dive-Cilium-Hubble-Overview/hubble-offerings-metrics-ui-cli.jpg) ### Hubble UI The Hubble UI delivers interactive dashboards and service maps: * **Service Dependency Map**\ Visualize inter-service communication to spot bottlenecks or misconfigurations. * **Flow Table**\ Inspect individual network flows with source/destination, protocol details, performance metrics, and policy verdicts. * **Security Events**\ Review blocked connections, policy violations, and external access attempts. Example service dependency graph: ![The image is a diagram from the Hubble UI showing a network of interconnected services, including "recruiter," "jobposting," "crawler," "coreapi," "loader," "elasticsearch," "kafka," and "zookeeper." Each service is represented with its respective ports and protocols.](https://kodekloud.com/kk-media/image/upload/v1752880401/notes-assets/images/Kubernetes-Networking-Deep-Dive-Cilium-Hubble-Overview/hubble-ui-network-services-diagram.jpg) Avoid exposing the Hubble UI publicly without proper authentication. Use port-forwarding or an ingress with strong access controls. #### Launching Hubble UI Locally Forward the UI port to your workstation: ```bash theme={null} cilium hubble ui # Forwarding from 0.0.0.0:12000 -> 8081 # Forwarding from [::]:12000 -> 8081 ``` Then browse to [http://localhost:12000](http://localhost:12000). ### Hubble CLI The Hubble CLI offers the same visibility in a terminal-friendly format, ideal for automation and scripts. Check the status inside a Cilium agent pod: ```bash theme={null} kubectl exec -it -n kube-system cilium-xxxxxx -c cilium-agent -- hubble status # Healthcheck (via unix:///var/run/cilium/hubble.sock): Ok # Current/Max Flows: 4,095/4,095 (100.00%) # Flows/s: 4.72 ``` #### Installing the Hubble CLI on Linux ```bash theme={null} HUBBLE_VERSION=$(curl -s https://raw.githubusercontent.com/cilium/hubble/master/stable.txt) HUBBLE_ARCH=amd64 if [ "$(uname -m)" = "aarch64" ]; then HUBBLE_ARCH=arm64 fi curl -L --fail --remote-name-all \ https://github.com/cilium/hubble/releases/download/$HUBBLE_VERSION/hubble-linux-${HUBBLE_ARCH}.tar.gz \ https://github.com/cilium/hubble/releases/download/$HUBBLE_VERSION/hubble-linux-${HUBBLE_ARCH}.tar.gz.sha256sum sudo tar xvzf hubble-linux-${HUBBLE_ARCH}.tar.gz -C /usr/local/bin rm hubble-linux-${HUBBLE_ARCH}.tar.gz.sha256sum ``` *** Next, we’ll dive into a hands-on demo to see Hubble in action. ## Links and References * [Cilium Documentation](https://docs.cilium.io/) * [Hubble on GitHub](https://github.com/cilium/hubble) * [Prometheus OpenMetrics](https://prometheus.io/docs/instrumenting/exposition_formats/) * [Grafana Dashboards](https://grafana.com/grafana/dashboards)