🔄 kube-copy: Kubernetes Pod File Syncer

kube-copy is a lightweight CLI utility to automatically synchronize local files into Kubernetes pods using kubectl cp. It watches your file system and Kubernetes pod lifecycle, keeping your app files up to date in development environments.

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🚀 Features

• ⚡️ Real-time file sync to running pods
• 🧠 Sync on pod restarts (via label selectors)
• 📁 Sync only on changes, with debounce
• ✅ Smart pod readiness check (all containers must be Ready)
• 📟 Optional post-sync command (e.g. touch a file or trigger reload)
• 📦 Simple JSON configuration
• 🧪 Designed for rapid local dev with K8s

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📦 Installation

Manual

cargo build --release
cp target/release/kube-copy /usr/local/bin

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📄 Configuration: watcher.json

[
  {
    "name": "sync-common",
    "kube_context": "minikube",
    "namespace": "default",
    "label_selectors": ["app=my-app"],
    "paths": [
      { "src": "./local/path", "dest": "/app/dest" }
    ],
    "post_sync_command": "touch /app/.reload"
  }
]

🔁 post_sync_command (optional)

If provided, this shell command is executed inside each pod via kubectl exec after each successful sync.

Use it to:

• Trigger live-reload scripts
• Touch a watched file (e.g. for nodemon)
• Run arbitrary shell hooks in your container

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🧰 Usage

kube-copy --config watcher.json

Options

Option	Description
--config	Path to config file (default: watcher.json)
--sync-on-start	Trigger sync to all ready pods at startup

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🛠 How it works

• Uses notify to track file changes
• Uses kube + kube-runtime to track pod events
• On trigger, uses kubectl cp to sync file/directory
• Ensures pods are Ready before syncing
• Optionally executes post_sync_command in pod via kubectl exec

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📌 When to Use

This tool is ideal for:

• Local development inside Kubernetes
• Replacing bind mounts / volumes in dev
• Hot reload / live update setups with fast iteration cycles

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💡 Why not ksync, telepresence, or skaffold?

Those tools are powerful, but often:

• Heavier in dependencies
• Require sidecars or privileged Daemons
• Use custom CRDs / controllers

kube-copy is zero-cluster-dependency: it's just you, your files, and your pods.

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📃 License

MIT © 2025 Dmitry Rusov