Overview of Monitoring in Kubernetes

Monitoring is crucial for understanding the state and performance of your Kubernetes cluster and applications. The main areas to focus on are:

  • Node and Pod Metrics: CPU, Memory, Disk, Network
  • Application Metrics: Custom metrics specific to your application
  • Logs: Error messages, application status
  • Tracing: Performance and flow of requests through services

Monitoring Tools: Prometheus and Grafana

Prometheus

Prometheus is an open-source monitoring solution that integrates well with Kubernetes. It collects metrics from configured targets at given intervals and stores them in a time-series database.

kubectl create -f prometheus-config.yaml

PromQL Query Example

sum(rate(http_requests_total[5m])) by (status_code)

Grafana

Grafana is often used in conjunction with Prometheus to visualize the collected data. You can set up Grafana dashboards to have real-time insights into your cluster’s state.

Dashboard Configuration

Navigate to Grafana dashboard -> Add Data Source -> Choose Prometheus

Kubernetes Logging

Logs provide essential information about the behavior and state of applications. In Kubernetes, you can fetch logs for a specific pod using:

kubectl logs POD_NAME

Or to get logs from a previous instance of a container:

kubectl logs -p POD_NAME

Application Tracing with Jaeger or OpenTracing

Jaeger

Jaeger helps with tracing the flow of requests across various microservices in your application.

OpenTracing

OpenTracing provides an API for integrating various tracing solutions. You can use it as a vendor-neutral way to add tracing to your applications.

Alerting and Notifications

Alerting ensures that you are notified when specific conditions in your monitoring data are met. Prometheus can evaluate alert rules and send notifications via Alertmanager.

Example Alert Rule in Prometheus

alert: HighCPU
expr: cpu_usage > 80%
for: 5m

Notification Channels

You can integrate Alertmanager with various notification channels like email, Slack, or PagerDuty.

kubectl create -f alertmanager-config.yaml