ernoaapa

Kubernetes CLI plugin for syncing and executing local files in Pod on Kubernetes

223 Stars 21 Forks Last release: over 1 year ago (v0.0.2) Apache License 2.0 22 Commits 2 Releases

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kubectl (Kubernetes CLI) plugin which is like

kubectl run

with

rsync

It creates temporary Pod and synchronises your local files to the desired container and executes any command.

Why

Sometimes you need to develop/execute your code in Kubernetes, because access to database, insufficient resources locally, need access to some specific device, use specific architecture, etc. The full build image, push, deploy cycle is way too slow for real development.

Use cases

This can be used for example to build and run your local project in Kubernetes where's more resources, required architecture, etc. while using your prefed editor locally.

Alternatives

```
kubectl cp
```
- Does full file copying, which is slow if a lot of files
NFS - requires a lot of extra installation and configuration

Other similar

telepresence - Executes locally and tunnels traffic from Kubernetes
docker-sync - Only for Docker

How it works

kubectl warp

is basically just combination of, simplified and modified version of

kubectl run

sshd-rsync

container and

kubectl port-forward

to access the container.

1. Start the Pod

First the

warp

generates temporary SSH key pair and and starts a temporary Pod with desired image and

sshd-rsync

container with the temporary public SSH public key as authorized key.

The

sshd-rsync

is just container with

sshd

daemon running in port 22 and

rsync

binary installed so the local

rsync

can sync the files to the shared volume over the SSH. The Pod have the

sshd-rsync

container defined twice, as init-container to make the initial sync before the actual container to start, and as a sidecar for the actual container to keep the files in-sync. The init-container waits one

rsync

execution and completes after succesfully so the actual containers can start.

2. Open tunnel

To sync the files with

rsync

over the SSH,

warp

opens port forwarding from random local port to the Pod port 22, what the

sshd-rsync

init- and sidecar-container listen.

3. Initial sync

At first, the Pod is in init state, and only the

sshd-rsync

is running and waiting for single sync execution. When the initial sync is done, the container completes succesfully so the Pod starts the actual containers.

The initial sync is needed so that we can start the actual container with any command. E.g. if we have shell script
test.sh
and when the container start with
./test.sh
as the command, the file must be there available before the execution.

4. Continuous syncing

When the initial sync is done, the actual container start with

sshd-rsync

as a sidecar. The

warp

command continuously run

rsync

command locally to update the files in the Pod.

Install

With Krew (Kubernetes plugin manager)

Install Krew, then run the following commands:

krew update
krew install warp

MacOS with Brew

brew install rsync ernoaapa/kubectl-plugins/warp

Linux / MacOS without Brew

Install rsync with your preferred package manager
Download
```
kubectl-warp
```
binary from releases
Add it to your
```
PATH
```

Usage

When the plugin binary is found from

PATH

you can just execute it through

kubectl

CLI

shell
kubectl warp --help

Basics

# Start bash in ubuntu image. Files in current directory will be synced to the container kubectl warp -i -t --image ubuntu testing -- /bin/bash

Start nodejs project in node container

Name: kubectl-warp
Brand: kubectl-warp
SKU: //ernoaapa/kubectl-warp
Rating: 2.3075 (223 reviews)

cd examples/nodejs kubectl warp -i -t --image node testing-node -- npm run watch

Exclude / Include

Sometimes some directories are too unnecessary to sync so you can speed up the initial sync with

--exclude

and

--include

flags, those gets passed to the

rsync

command, for more info see rsync manual ```shell

Do not sync local node_modules, because we fetch dependencies in the container as first command

cd examples/nodejs kubectl warp -i -t --image node testing-node --exclude="node_modules/***" -- npm install && npm run watch ```

Examples

There's some examples with different languages in examples directory

Development

Prerequisites

Golang v1.11
Go mod enabled

Build and run locally

go run ./main.go --image alpine -- ls -la

Syncs your local files to Kubernetes and list the files

Build and install locally

go install .

Now you can use `kubectl`

kubectl warp --help

kubectl-warp

by ernoaapa