AWS Secrets Manager vs. External Secrets Operator

Secrets as a Cloud Service or as Part of the Kubernetes Platform

Secrets are among the most sensitive components of modern applications. Credentials, API keys, tokens, or certificates determine whether systems communicate securely—or whether security boundaries effectively do not exist. Thus, the question of where and how secrets are managed and consumed is far-reaching.

AWS Secrets Manager and the External Secrets Operator address this very issue, albeit from fundamentally different perspectives. One anchors secrets in the cloud platform. The other deliberately integrates them into Kubernetes as a central control plane. The difference is not functional—it’s architectural.

AWS Secrets Manager: Secret Management as a Cloud Service

AWS Secrets Manager is AWS’s managed service for storing and managing sensitive information such as credentials, API keys, or certificates. Secrets are stored encrypted, versioned, and can be automatically rotated, especially in combination with AWS services like RDS or IAM.

The integration with AWS services is deep. Applications access them via AWS APIs, permissions follow IAM logic, and audit logs run through CloudTrail. The operational effort is low, and billing is usage-based per secret and API access. For AWS-centric architectures, this is convenient and consistent.

However, this strength is also a structural limitation.

Cloud Binding as an Implicit Architectural Decision

Secrets Manager is bound to AWS—both technically and organizationally. Applications must use AWS-specific APIs, access models follow IAM, and rotation mechanisms are tailored to supported services.

In [Kubernetes] environments, Secrets Manager remains an external component. Pods do not consume secrets natively but indirectly: via sidecars, SDKs, CSI drivers, or synchronization mechanisms. Kubernetes becomes the execution site, not the control plane for secrets.

The platform logic of Kubernetes is thus supplemented by a proprietary dependency. Applications implicitly know which cloud they are running in.

External Secrets Operator: Kubernetes as a Secret Hub

The External Secrets Operator addresses this very interface. As an open-source component for Kubernetes, it synchronizes secrets from external backends into native Kubernetes Secrets.

Different sources are supported, including AWS Secrets Manager, HashiCorp Vault, Azure Key Vault, or other compatible systems. The operator itself does not store secrets permanently. It merely defines how secrets get from a backend into the cluster—not where they are created or managed.

This consciously shifts responsibility.

Architecture: Decoupling Use and Management

The architectural difference is significant. With the External Secrets Operator, Kubernetes becomes the central control plane for secret usage. Applications consume secrets through standardized [Kubernetes] mechanisms—independent of the underlying backend.

Configuration is declarative, versionable, and GitOps-capable. Secrets are described via custom resources, not imperative API calls. Changing the backend requires no workload adjustments, just a change in the operator configuration.

Secrets follow the platform—not the provider.

Portability as a Design Goal

This approach fits platform architectures designed for openness and portability. [Kubernetes] clusters can be operated in different clouds or on-premises, while secret handling remains consistent.

Security models are oriented towards [Kubernetes] RBAC, namespaces, and service accounts—not solely IAM policies of a single provider. Secrets are provided where needed, without the application logic needing to know cloud-specific dependencies.

Especially in multi-cluster or hybrid scenarios, this is not a nice-to-have but a prerequisite for clean architecture.

Responsibility Consciously Distributed

The additional design flexibility brings responsibility. The External Secrets Operator does not handle encryption in the backend or automatic rotation. These tasks remain with the respective secret stores.

This creates a clear separation:

• Secret creation and management in the backend
• Secret usage in the [Kubernetes] platform

This separation makes the model stable in the long term. Backends are interchangeable, platform logic remains constant, applications remain unchanged.

Practical Consequences in [Kubernetes] Environments

In [Kubernetes]-centered environments, the difference becomes quickly apparent. AWS Secrets Manager simplifies secret management within AWS. The External Secrets Operator integrates secrets into the platform itself.

Kubernetes becomes not just runtime but also a security and control plane. Workloads remain portable, deployments reproducible, dependencies explicit.

Secrets are not consumed—they are integrated.

Condensed Comparison

When Each Approach Makes Sense

AWS Secrets Manager is suitable for:

• purely AWS-centric workloads
• tight integration with AWS services
• low requirements for [Kubernetes] portability
• focus on minimal operational effort

The External Secrets Operator is suitable for:

• [Kubernetes]-centered platform architectures
• multi-cloud or hybrid scenarios
• GitOps-based operational models
• clean separation of platform and cloud
• long-term portability and sovereignty

Conclusion

Secrets are not an implementation detail. They define how tightly applications are bound to their infrastructure.

AWS Secrets Manager subordinates secret management to the cloud. The External Secrets Operator integrates secrets into the platform itself.

The difference is not technical but structural. Those who use secrets as a cloud function accept dependency. Those who understand them as part of the [Kubernetes] platform keep the application architecture flexible—today and in the future.