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kat - Real-time Log Streaming for Kubernetes

kat (Kubernetes Attach & Tail Pod Logs) lets you stream logs from all containers across any number of namespaces in real-time. Think of it as tail -f for your entire Kubernetes cluster.

# Stream logs from your frontend namespace
kat frontend

# Stream from multiple namespaces and save to disk
kat --tee /tmp/logs frontend backend monitoring

Why kat?

Managing logs across a Kubernetes cluster is challenging:

  • kubectl logs requires separate commands for each pod
  • You have to manually reattach when pods restart
  • New pods are easily missed
  • Multiple terminal windows needed for multiple namespaces

kat solves these problems by:

  • Automatically discovering and attaching to all pods
  • Handling pod restarts and new pod creation
  • Streaming logs from all containers simultaneously
  • Supporting multiple namespaces in a single command
  • Saving logs to disk with automatic directory organization

Quick Start

  1. Install:

    go install github.com/frobware/kat/cmd/kat@latest

  2. Run:

    # Stream all logs from current namespace
kat

# Stream from specific namespaces
kat frontend backend

# Stream and save logs to disk
kat -d frontend  # Creates timestamped directory in /tmp

Basic Usage

Stream logs to console

# Single namespace
kat frontend

# Multiple namespaces
kat frontend backend monitoring

Save logs to disk

# Auto-create timestamped directory
kat -d frontend
→ Using temporary log directory: /tmp/kat-2025-01-06T15:30:00

# Specify output directory
kat --tee /tmp/my-logs frontend

# Save logs but hide console output
kat --tee /tmp/logs --silent frontend

Directory Structure

When saving logs (using -d or --tee), kat creates this structure:

/output-dir/
  └── namespace/
      └── pod-name/
          └── container-name.txt

Common Options

Flag Description Default
--since duration Show logs from last N minutes 1m
-d Auto-create temp directory in /tmp -
--tee string Write logs to specified directory -
--silent Disable console output false
--allow-existing Allow writing to existing directory false

Advanced Configuration

For high-throughput clusters or specific requirements:

Flag Description Default
--qps float Kubernetes client QPS 500
--burst int Kubernetes client burst rate 1000
--kubeconfig string Path to kubeconfig ~/.kube/config

How It Works

┌──────────┐    ┌───────────┐    ┌──────────┐
│  Pod 1   │    │           │    │ Console  │
│ Container├────┤           ├────┤          │
│ Logs     │    │    kat    │    │          │
├──────────┤    │           │    ├──────────┤
│  Pod 2   │    │ Automatic │    │          │
│ Container├────┤ Discovery ├────┤  Files   │
│ Logs     │    │    &      │    │          │
├──────────┤    │ Streaming │    │          │
│   ...    │    │           │    │          │
└──────────┘    └───────────┘    └──────────┘

kat uses Kubernetes informers to watch for pod lifecycle events, automatically attaching to new pods and detaching from terminated ones. All container logs are streamed in real-time and can be displayed on the console and/or saved to disk.

License

MIT License - see LICENSE for details.