Testing Stack with Secrets

version: '3.9'
services:
  app:
    image: nginx
    secrets:
      - app-secret

secrets:
  app-secret:
    external: true

Adding Certificate Secrets

1. Encode certificate

# Linux/Mac
base64 -w0 certificate.pfx

# Windows PowerShell
[Convert]::ToBase64String([IO.File]::ReadAllBytes("certificate.pfx"))

2. Create secret in Portainer

• Navigate to Secrets
• Click “Add secret”
• Encode secret: OFF (already base64 encoded)
• Paste encoded value
• Save

3. Reference in stack

services:
  app:
    secrets:
      - source: cert-secret
        target: /app/cert.pfx

secrets:
  cert-secret:
    external: true