Use Cloudflare R2 with MinIO Gateway for Kestra

This guide demonstrates how to use Cloudflare R2 as an object storage backend through an S3-compatible interface, exposed to Kestra via a MinIO Gateway. This setup enables Kestra to continue using S3 storage without requiring configuration changes.

Create an R2 Bucket

Log into Cloudflare Dashboard and create a new R2 bucket:

  1. Navigate to R2 → Create Bucket
  2. Choose a name like kestra-bucket

Generate Access Keys

Go to API Tokens → R2 Keys and create a new key pair:

  • access_key_id: Your user access key
  • secret_access_key: Your secret key

Be sure to save these credentials securely.

Retrieve the R2 Endpoint

Cloudflare R2 provides a static S3-compatible endpoint:

https://<ACCOUNT_ID>.r2.cloudflarestorage.com

Replace <ACCOUNT_ID> with your Cloudflare account ID, found in the R2 dashboard.

Set Up MinIO Gateway to R2

MinIO will act as a gateway, forwarding all S3 traffic to Cloudflare R2.

docker-compose.yml

version: '3.8'


services:
  minio:
    image: minio/minio:latest
    container_name: minio-r2-gateway
    command: gateway s3 https://<ACCOUNT_ID>.r2.cloudflarestorage.com
    environment:
      MINIO_ROOT_USER: <R2_ACCESS_KEY>
      MINIO_ROOT_PASSWORD: <R2_SECRET_KEY>
    ports:
      - "9000:9000"
    restart: always

Replace <ACCOUNT_ID>, <R2_ACCESS_KEY>, and <R2_SECRET_KEY> with your actual Cloudflare and access values.

Validate Setup with MinIO Client

Install the MinIO Client (mc):

mc alias set r2 http://localhost:9000 <R2_ACCESS_KEY> <R2_SECRET_KEY>
mc mb r2/kestra-bucket
mc ls r2

Configure Kestra (No Changes Required)

Since Kestra supports MinIO-compatible S3 endpoints, no changes to your configuration are required:

storage:
  type: minio
  minio:
    endpoint: localhost
    port: 9000
    bucket: kestra-bucket
    access-key: <R2_ACCESS_KEY>
    secret-key: <R2_SECRET_KEY>

Kestra will interact with MinIO, which in turn proxies to R2.

Test with a Flow

id: r2_test_flow
namespace: company.team


tasks:
  - id: write_output
    type: io.kestra.plugin.scripts.python.Script
    taskRunner:
      type: io.kestra.plugin.scripts.runner.docker.Docker
      containerImage: ghcr.io/kestra-io/pydata:latest
    outputFiles:
      - r2-output.json
    script: |
      import json
      from kestra import Kestra
      data = {'message': 'stored in R2'}
      Kestra.outputs(data)
      with open('r2-output.json', 'w') as f:
          json.dump(data, f)

Then, verify the file was stored correctly using:

mc cat r2/kestra-bucket/main/company/team/r2_test_flow/...

Expected output:

{"message": "stored in R2"}%

References

You now have Cloudflare R2 configured as your object storage backend for Kestra, fully integrated via MinIO Gateway.