​Configure ​Local ​Min​I​O ​Storage for ​Kestra

Set up and verify a local MinIO storage backend for Kestra using the mc CLI and Docker.

Install and Configure mc (MinIO Client)

Download and install the MinIO Client (mc) tool using the following command:

curl https://dl.min.io/client/mc/release/linux-amd64/mc --create-dirs -o $HOME/minio-binaries/mc && \
chmod +x $HOME/minio-binaries/mc && \
export PATH=$PATH:$HOME/minio-binaries/

Remove and Recreate Local Alias

Remove any existing local alias:

mc alias remove local

Recreate the alias with your MinIO access credentials:

mc alias set local http://localhost:9000 YOUR_ACCESS_KEY YOUR_SECRET_KEY

Create a Local Bucket

Create the bucket where outputs will be stored:

mc mb local/your-bucket

Start MinIO Server

Run the MinIO Docker container using the dedicated CI Compose file (e.g., from kestra-io/storage-minio):

docker compose -f docker-compose-ci.yml up

Configure Kestra for MinIO Storage

Update your application-psql.yml (or other relevant configuration file) under the kestra: section:

storage:
  type: minio
  minio:
    endpoint: localhost
    port: 9000
    bucket: your-bucket
    access-key: YOUR_ACCESS_KEY
    secret-key: YOUR_SECRET_KEY

Launch Kestra

Start Kestra as usual. Ensure the updated configuration file is correctly mounted or included.

Test with a Flow that Produces Outputs

Here is a sample flow that generates output files and logs intermediate data:

id: alligator_743987
namespace: company.team

tasks:
  - id: pass_output
    type: io.kestra.plugin.core.debug.Return
    format: hello

  - id: py_outputs
    type: io.kestra.plugin.scripts.python.Script
    taskRunner:
      type: io.kestra.plugin.scripts.runner.docker.Docker
      containerImage: ghcr.io/kestra-io/pydata:latest
    outputFiles:
      - myoutput.json
    script: |
      import json
      from kestra import Kestra
      my_kv_pair = {'mykey': 'from Kestra'}
      Kestra.outputs(my_kv_pair)
      with open('myoutput.json', 'w') as f:
          json.dump(my_kv_pair, f)

  - id: take_inputs
    type: io.kestra.plugin.core.log.Log
    message: |
      data from previous tasks: {{ outputs.pass_output.value }} and {{ outputs.py_outputs.vars.mykey }}

  - id: check_output_file
    type: io.kestra.plugin.scripts.shell.Commands
    taskRunner:
      type: io.kestra.plugin.core.runner.Process
    commands:
      - cat {{ outputs.py_outputs.outputFiles['myoutput.json'] }}

Verify Output in MinIO Bucket

You can now validate that the output file is stored in the MinIO bucket:

mc cat local/your-bucket/main/company/team/alligator-743987/executions/23z9cJWEa23kNAxu6sm0CT/tasks/py-outputs/5kxYRM7UqUurvnpVNvHca7/1noPFEiCFGPf2hcqjVzywu-myoutput.json

Note that you may need to replace the following placeholders with your own values:

• the bucket name (here your-bucket)
• the path (namespace) (here company/team)
• the flow id (here alligator-743987)
• the execution id (here 23z9cJWEa23kNAxu6sm0CT)
• the task id (here py-outputs)
• and finally the output file name (here 1noPFEiCFGPf2hcqjVzywu-myoutput.json)

The result should look like:

{"mykey": "from Kestra"}%

You have successfully configured and validated MinIO as a local storage backend for Kestra.