Tail Kubernetes Logs Efficiently with Stern

Monitoring logs in Kubernetes is essential for debugging and troubleshooting. While kubectl logs -f pod-name works for individual pods, it becomes difficult when dealing with multiple pods in a deployment. Sometimes we end up opening multiple terminal tabs to follow logs. Well, stern can be a better alternative.

Why Use Stern?

• Allows tailing logs from multiple pods simultaneously
• Supports regex filtering for better log analysis
• Works with multi-container pods
• Provides color-coded output for better readability

Installing Stern

• macOS: brew install stern
• Linux:

curl -Lo stern 
https://github.com/wercker/stern/releases/download/{VERSION}/stern_linux_amd64
chmod +x stern
sudo mv stern /usr/local/bin/

Note:

To illustrate some of the commands, I'll use meetings-summarizer as my deployment.

Using Stern for Log Tailing

• Tail logs from all pods in a deployment

  stern meetings-summarizer

• Tail logs from a specific container in a pod

  stern meetings-summarizer -c backend

• Follow logs from the deployment pods across all namespaces

  stern meetings-summarizer --all-namespaces

• Filter logs using regex

  stern meetings-summarizer | grep "ERROR"

• Exclude unwanted log patterns

  stern meetings-summarizer --exclude "healthcheck"

• Enable colorized output for better readability

  stern meetings-summarizer --color=always

When to Use Stern?

• Debugging microservices that generate logs across multiple pods
• Monitoring real-time logs for deployments
• Filtering logs for specific containers or error messages
• Analyzing logs in large-scale Kubernetes environments

Stern simplifies log management in Kubernetes, making it easier to diagnose and resolve issues efficiently. I hope you find this article useful.