/gke-observability

GKE Observability

This reference covers monitoring, logging, and metrics configuration for GKE. The golden path enables comprehensive observability including control-plane metrics.

MCP Tools: get_cluster, list_k8s_events, get_k8s_logs, get_k8s_cluster_info, describe_k8s_resource. CLI-only: gcloud container clusters update --monitoring=..., gcloud logging read

Golden Path Observability Defaults

Control-Plane Metrics (Golden Path Addition)

The golden path adds three control-plane monitoring components not present in default clusters:

These are critical for diagnosing cluster-level issues (slow API responses, scheduling delays, stuck controllers).

Enabling Full Monitoring

Say this whenever you hand over a --monitoring command:

1. Control-plane metrics are NOT enabled by default. State this outright in your answer — do not leave it implied by the fact that you are supplying an enable command. API_SERVER, SCHEDULER, and CONTROLLER_MANAGER are off on every new cluster and collect nothing until explicitly turned on, and the same is true of DCGM, CADVISOR, KUBELET, and kube-state (POD, DEPLOYMENT, STATEFULSET, DAEMONSET, HPA, STORAGE, JOBSET). SYSTEM is the only package on by default. A user asking "why are there no API server metrics" has almost always simply never enabled them.
2. The flag replaces, it does not append. The set supplied to --monitoring overrides the previous setting entirely, so omitting a component silently turns it off. Always pass the full desired list, and always include SYSTEM — it cannot be disabled while monitoring is on, and never on Autopilot.
3. These metrics bill per sample ingested via Managed Service for Prometheus. Enabling the full suite on a large cluster is a real cost increase; mention it rather than presenting the list as free.

The gcloud flag and the API field use different spellings for the same components. Do not copy names between them:

Component	gcloud --monitoring=	monitoringConfig API enum
System	SYSTEM	SYSTEM_COMPONENTS
API server	API_SERVER	APISERVER
Controller mgr	CONTROLLER_MANAGER	CONTROLLER_MANAGER

The remaining components share a spelling. Using an API enum in the CLI flag (or the reverse) fails the command — this is a common and confusing error.

# Enable golden path monitoring suite
gcloud container clusters update <CLUSTER_NAME> --region <REGION> \
  --monitoring=SYSTEM,API_SERVER,SCHEDULER,CONTROLLER_MANAGER,STORAGE,POD,DEPLOYMENT,STATEFULSET,DAEMONSET,HPA,JOBSET,CADVISOR,KUBELET,DCGM \
  --quiet

# Enable Managed Prometheus
gcloud container clusters update <CLUSTER_NAME> --region <REGION> \
  --enable-managed-prometheus \
  --quiet

# Enable Dataplane V2 observability metrics
gcloud container clusters update <CLUSTER_NAME> --region <REGION> \
  --enable-dataplane-v2-flow-observability \
  --quiet

Managed Prometheus

Golden path enables Google Managed Prometheus for metrics collection and querying.

Querying metrics:

• Use Cloud Monitoring Metrics Explorer in the console
• Use PromQL via the Prometheus UI or API
• Grafana dashboards via Managed Grafana

Key GKE metrics:

Live Resource Usage (kubectl-only)

No MCP or gcloud equivalent exists for live resource usage. Use kubectl top:

kubectl top pods --all-namespaces --sort-by=cpu
kubectl top nodes
kubectl top pods --containers -n <NAMESPACE>  # per-container breakdown

Cloud Logging (gcloud-only)

Querying cluster logs (no MCP equivalent — use gcloud logging read):

# System component logs
gcloud logging read \
  'resource.type="k8s_cluster" AND resource.labels.cluster_name="<CLUSTER_NAME>"' \
  --project <PROJECT_ID> --limit 50 \
  --quiet

# Workload logs for a specific namespace
gcloud logging read \
  'resource.type="k8s_container" AND resource.labels.cluster_name="<CLUSTER_NAME>" AND resource.labels.namespace_name="<NAMESPACE>"' \
  --project <PROJECT_ID> --limit 50 \
  --quiet

# Audit logs (who did what)
gcloud logging read \
  'resource.type="k8s_cluster" AND logName:"cloudaudit.googleapis.com"' \
  --project <PROJECT_ID> --limit 50 \
  --quiet

Diagnostic Settings

For security monitoring and troubleshooting, enable control-plane audit logs:

# View current logging config
gcloud container clusters describe <CLUSTER_NAME> --region <REGION> \
  --format="yaml(loggingConfig)" \
  --quiet

Alerting

Set up alerts for critical conditions:

Prerequisite: The kube_* series above (e.g., kube_pod_status_phase, kube_pod_container_status_restarts_total, kube_node_status_condition) come from kube-state-metrics, which GKE does not collect by default. Deploy the Managed Prometheus kube-state-metrics package first.

Proposing Dashboards & Alerts (Production Rules)

When designing or proposing alerting and dashboard strategies for GKE:

1. Always explicitly name Google Cloud Monitoring as the platform to implement these alerts and dashboards.
2. Always include API server latency (via apiserver_request_duration_seconds metric) on the dashboard as a critical indicator of control plane health, alongside node CPU/Memory and pod crash loops.

Node Health (Production Rules)

A comprehensive assessment of node health relies on analyzing these two metrics together:

1. kubernetes.io/node/status_condition (filtered by status_condition="Ready"): Use this to track healthy nodes. Note that it will only report values for nodes that have successfully bootstrapped.
2. compute.googleapis.com/instance_group/size (filtered by instance_group_name="gke-<cluster_name>-.*"): Use this to track the total number of nodes in a specific cluster. Note that it does not differentiate between healthy and unhealthy nodes.

Cost Considerations

Monitoring and logging have associated costs:

• Cloud Logging: Charged per GiB ingested beyond free tier (50 GiB/project/month)
• Cloud Monitoring: Free for GKE system metrics; custom metrics charged per time series
• Managed Prometheus: Charged per samples ingested

To reduce costs in non-production:

# Reduce to system-only monitoring
gcloud container clusters update <CLUSTER_NAME> --region <REGION> \
  --monitoring=SYSTEM \
  --quiet

Distributed Tracing & Continuous Profiling (Recommended)

Not golden path defaults — recommended for production microservice architectures and performance-sensitive workloads.

• Cloud Trace: Add OpenTelemetry SDK to your app with the opentelemetry-operations-go (or equivalent) exporter. Traces appear in Cloud Trace console. Identifies cross-service latency bottlenecks.
• Cloud Profiler: Add the Cloud Profiler agent to your app. Profiles CPU and memory usage in production with low overhead. Identifies hotspots and compares across versions.

Recent additions:

• Managed OpenTelemetry for GKE (Preview): Managed in-cluster OTLP endpoint plus auto-instrumentation for traces, metrics, and logs. Requires GKE 1.34.1-gke.2178000+; enable with gcloud beta container clusters update ... --managed-otel-scope=COLLECTION_AND_INSTRUMENTATION_COMPONENTS.
• PSI (Pressure Stall Information) metrics: cAdvisor container_pressure_{cpu,memory,io}_{waiting,stalled}_seconds_total series (beta in Kubernetes 1.34) can be collected via a Managed Prometheus ClusterNodeMonitoring resource; GKE's documented collection path requires GKE 1.35+.

LQL Query Examples

Common Logging Query Language patterns for GKE troubleshooting:

# Error logs for a specific container
resource.type="k8s_container" AND resource.labels.container_name="my-app" AND severity>=ERROR

# OOMKilled events
resource.type="k8s_event" AND jsonPayload.reason="OOMKilling"

# Pod scheduling failures
resource.type="k8s_event" AND jsonPayload.reason="FailedScheduling"

# Audit logs (who did what)
resource.type="k8s_cluster" AND logName:"cloudaudit.googleapis.com"

Troubleshooting Managed Prometheus (GMP)

Diagnose GMP ingestion, rule, and query problems. Stay read-only (kubectl get / describe / logs) and propose config changes; do not mutate live resources directly.

First: split ingestion-side vs query-side

Before anything else, query the up metric in the Metrics Explorer PromQL tab in Cloud Monitoring. If up returns data, ingestion works and the problem is query-side (Grafana / PromQL / permissions). If up is empty, the problem is ingestion-side (collectors, scrape config, or write permission).

Ingestion-side

1. Check GMP system pods. They run in gmp-system on Standard clusters and gke-gmp-system on Autopilot. Look for gmp-operator, collector (DaemonSet), and rule-evaluator not Running or with high restarts:

   kubectl get pods -n gmp-system            # gke-gmp-system on Autopilot
   kubectl logs -n gmp-system -l app.kubernetes.io/name=collector -c prometheus

   A collector in CrashLoopBackOff with OOMKilled usually means high metric cardinality - drop unneeded series/labels (see cost section below) or apply a VPA to the collector.

2. Check PodMonitoring / ClusterPodMonitoring. The three classic mistakes:

   • spec.selector.matchLabels does not match the target Pod labels.
   • A PodMonitoring only discovers targets in its own namespace - use ClusterPodMonitoring for cluster-wide scope.
   • spec.endpoints.port must reference the named container port (e.g. port: web), not the port number.

3. Enable target status for scrape errors. Propose patching OperatorConfig in gmp-public with features.targetStatus.enabled: true; once applied, kubectl describe podmonitoring <name> and read Active Targets, Unhealthy Targets, and Last Error (for example connection refused, HTTP 404, context deadline exceeded). Disable it again when done - it can OOM the operator on large clusters.

Permissions (403 / no data written)

GMP components inherit the node service account. Ingestion needs roles/monitoring.metricWriter (error Permission monitoring.timeSeries.create denied in collector logs); the rule-evaluator and query paths need roles/monitoring.viewer (403 / PermissionDenied). If a query app (like Grafana) uses Workload Identity, the bound Google service account also needs roles/monitoring.viewer.

Rule and alert evaluation

Rule scope is decided by the resource kind: Rules (single namespace), ClusterRules (whole cluster), and GlobalRules (all data in the metrics scope). You must use GlobalRules to write rules against Cloud Monitoring metrics - a Rules/ClusterRules resource silently returns no data for them. Check rule-evaluator logs (-c evaluator) for parse/permission errors.

Query-side (Grafana / PromQL)

• Data source must point at the GMP frontend query proxy, not localhost:9090, and the HTTP Method must be GET - POST fails with no match[] parameter provided.
• Grafana template variables: use the two-argument form label_values(<metric>, <label>); the single-argument label_values(<label>) is not supported by the GMP API.
• Cloud Monitoring metrics that exist for multiple resource types need a monitored_resource label matcher, otherwise the query fails with series selector must specify a label matcher on monitored resource name.

Cost, cardinality, and quota

Use the Cloud Monitoring Metrics Management page to find the metrics driving billable samples and high cardinality. Reduce them with metricRelabeling in the PodMonitoring (action: drop for whole metrics, action: labeldrop for unbounded labels like user_id/request_id) or by raising the scrape interval. 429 / RESOURCE_EXHAUSTED errors mean you have hit the Cloud Monitoring API ingestion or query quota - optimize first, then request a quota increase.

Supporting Links

• GKE system metrics
• GKE Observability Documentation
• Google Cloud Managed Service for Prometheus
• Troubleshoot Managed Service for Prometheus
• Rule evaluation (Rules / ClusterRules / GlobalRules)
• Cloud Logging Query Language (LQL)
• Google Cloud Monitoring Alerts