Design Principles

Docker Secret Operator (DSO) is guided by a set of core principles that prioritize security, operational simplicity, and native integration. Every feature and architectural decision must align with these pillars.

---

1. Zero Persistence by Default

Secrets should never touch persistent storage.

• The Rule: No .env files, no host-path mounts for plaintext secrets, and no secret data in image layers.
• The Implementation: Secrets are held in the agent's RAM and injected via tmpfs mounts or the CopyToContainer API.

2. Event-Driven Reconciliation

DSO is not a one-time "fetch and forget" tool. It is a state reconciler.

• The Rule: The system must respond immediately to changes in either the source (Vault) or the destination (Docker).
• The Implementation: A continuous Control Loop (Watch-Analyze-Inject) ensuring the "Actual State" always matches the "Desired State."

3. Docker-Native Experience

DSO should feel like a first-class citizen of the Docker ecosystem.

• The Rule: No complex external dependencies or sidecar architectures where possible.
• The Implementation: Native CLI plugin support (docker dso), metadata-driven discovery via Labels, and interaction through the standard Docker Unix socket.

4. Least Privilege / Machine Identity

Human intervention in secret management should be minimized to prevent credential leakage.

• The Rule: Eliminate static credentials (API Keys, Client Secrets) on the host.
• The Implementation: Deep integration with cloud-native identity providers (AWS IAM, Azure Managed Identity) so the host "is" the credential.

5. Atomic and Non-Destructive Rotation

Secret updates should never leave an application in a partially-configured or broken state.

• The Rule: Updates must be all-or-nothing and verified for health.
• The Implementation: Tar-streamed injection and intelligent rotation strategies that wait for health-checks before removing old container instances.

---

Why These Principles Matter

By strictly adhering to these principles, DSO provides a security model that is significantly more robust than traditional Docker secret management, while maintaining the simplicity that makes Docker the preferred choice for many engineering teams.

Next Steps

• System Architecture: See how these principles are implemented.
• Security Model: Detailed threat mitigations.
• Production Readiness: Deploying DSO in high-security environments.