prometheus-query

Query Prometheus metrics, alerts, and cluster status using PromQL with options for direct URL or Kubernetes port-forward access.

Prometheus Monitoring Query

Query metrics, alerts, and cluster status from Prometheus.

Two Access Modes

1. Direct URL Access (Recommended)

Use when Prometheus is accessible via network (cloud service, remote server, etc.):

bash

# Using remote Prometheus URL
python scripts/query_prometheus.py \
  --prom-url "https://prometheus.example.com" \
  --query "up"

# Query alerts
python scripts/query_prometheus.py \
  --prom-url "https://prometheus.example.com" \
  --alerts

2. Kubernetes Port-Forward

Use when Prometheus is only accessible via kubectl:

bash

# Terminal 1: Port-forward Prometheus
kubectl port-forward -n prometheus svc/prometheus 9090:9090

# Terminal 2: Query metrics
python scripts/query_prometheus.py \
  --prom-url "http://localhost:9090" \
  --query "up"

Query Script

Use scripts/query_prometheus.py to query metrics:

bash

# Query a specific metric (default: http://localhost:9090)
python scripts/query_prometheus.py --query "up"

# Explicit URL
python scripts/query_prometheus.py \
  --prom-url "http://localhost:9090" \
  --query "rate(http_requests_total[5m])"

# Query alerts
python scripts/query_prometheus.py --alerts

Default: If --prom-url is not specified, uses http://localhost:9090.

Common Query Types

Alerts

promql

# All firing alerts
ALERTS{alertstate="firing"}

# Pending alerts
ALERTS{alertstate="pending"}

Cluster Status

promql

# Node status
kube_node_status_condition{condition="Ready"}

# Pod status
kube_pod_status_phase{phase="Running"}
kube_pod_status_phase{phase="Failed"}

# Namespace pod counts
count by (namespace) (kube_pod_info)

Nginx Metrics

promql

# Request rate
rate(nginx_http_requests_total[5m])

# Connection stats
nginx_connections_active
nginx_connections_reading
nginx_connections_writing
nginx_connections_waiting

# Request duration (p99)
histogram_quantile(0.99, rate(nginx_http_request_duration_seconds_bucket[5m]))

Custom Metrics

Replace <metric_name> with your actual metric:

promql

# Current value
<metric_name>

# Rate over 5 minutes
rate(<metric_name>[5m])

# Average over 1 hour
avg(<metric_name>[1h])

Parameters

• prom-url: Prometheus URL (default: http://localhost:9090)
• query: PromQL query string
• alerts: Flag to query all alerts with states
• time: Evaluation timestamp (ISO 8601)
• start: Start time for range query
• end: End time for range query
• step: Query resolution step (for range queries)
• timeout: Query timeout in seconds (default: 30)

Output

Returns formatted metric results. For instant queries, returns current values. For alerts, returns alert name, state (firing/pending), and labels.

Examples

Check cluster health

bash

# All firing alerts
python scripts/query_prometheus.py --alerts

# Node status
python scripts/query_prometheus.py --query "kube_node_status_condition{condition='Ready'}"

Nginx load

bash

# Request rate
python scripts/query_prometheus.py --query "rate(nginx_http_requests_total[5m])"

# Active connections
python scripts/query_prometheus.py --query "nginx_connections_active"

Custom metric

bash

python scripts/query_prometheus.py --query "my_custom_metric"
python scripts/query_prometheus.py --query "rate(my_custom_metric[5m])"