# Stern — Multi-Pod Multi-Container Log Tailing for Kubernetes

> The missing multi-Pod tail -f for Kubernetes. Follows every matching Pod and container with color-coded names — the first tool SREs install after kubectl.

## Install

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# Stern — Multi-Pod Multi-Container Log Tailing for Kubernetes

## Quick Use
```bash
# install on macOS / Linux
brew install stern            # or: go install github.com/stern/stern@latest

# tail every Pod matching a regex, across all namespaces
stern '.*' -A

# tail one deployment's containers with color-coded Pod names
stern --selector app=checkout --since 10m

# include init containers, exclude debug sidecars, JSON output
stern checkout-* --container-state all --exclude-container istio-proxy -o json

# follow only error lines
stern payments -i 'ERROR|panic'
```

## Introduction
Stern is the missing multi-Pod `tail -f` for Kubernetes. Where `kubectl logs` can only tail one Pod's one container, Stern glues every matching Pod and every container together into a single colored stream. It is the first thing most SREs install after kubectl, and one of the few tools that works identically on kind, EKS, and air-gapped clusters.

## What Stern Does
- Tails logs from multiple Pods and containers with a single regex or label selector
- Color-codes Pod names so interleaved logs stay readable
- Follows rolling deployments — new Pods are picked up automatically
- Supports time windows (`--since`, `--tail`) and include/exclude regexes
- Emits JSON or raw output for pipelines into `jq`, Loki, or a file

## Architecture Overview
Stern is a small Go binary. It talks to the Kubernetes API via your kubeconfig, watches Pods matching the query, and opens a streaming log request against each matched container. It maintains a concurrency-safe writer that interleaves lines with a Pod prefix; when Pods come and go (restarts, rollouts, preemption) Stern silently reattaches without dropping the overall session.

## Self-Hosting & Configuration
- Single static binary — drop into `/usr/local/bin` and go
- Obeys `$KUBECONFIG` and `--context`, same as kubectl
- Shell completions via `stern --completion=bash|zsh|fish`
- Configurable templates (`--template`) for log prefixes
- Plays well with `fzf` for interactive Pod selection in a shell alias

## Key Features
- Regex and label selectors with `--selector`
- Container-state filter — show init, sidecars, or just running
- `--prompt` wraps stern with an fzf-based interactive picker
- JSON output mode feeds structured-log stores directly
- Works across namespaces with `--all-namespaces` / `-A`

## Comparison with Similar Tools
- **kubectl logs** — single Pod / container only; Stern is the multi-stream upgrade
- **kail** — older, similar tool; less active maintenance
- **kubetail** — bash script wrapper; fine for small clusters but lacks streaming
- **Loki + logcli** — centralized store; great for history, not for live tailing
- **k9s log pane** — built into k9s but one Pod at a time

## FAQ
**Q: How is this different from kubectl logs -f?**
A: Stern streams every matching Pod and container concurrently, with colored prefixes. kubectl logs targets one.

**Q: Can I tail across namespaces?**
A: Yes — `-A` or `--all-namespaces` scopes across the whole cluster (subject to RBAC).

**Q: Does it support kube-proxy or private clusters?**
A: Yes — whatever your kubeconfig can reach, Stern can stream from.

**Q: How do I filter noisy sidecar logs?**
A: `--exclude-container istio-proxy,linkerd-proxy` drops them from the stream.

## Sources
- https://github.com/stern/stern
- https://github.com/stern/stern#installation


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Source: https://tokrepo.com/en/workflows/f3a966bd-3900-11f1-9bc6-00163e2b0d79
Author: AI Open Source