Security and Compliance in Multi-Cluster Environments

Enterprises increasingly run applications, data pipelines, API gateways, and machine-learning services across multiple Kubernetes and cloud clusters. This distribution improves locality, resilience, and provider flexibility, but it also fragments identity, policy enforcement, audit evidence, and compliance reporting. A control that is correctly applied in one cluster can drift in another, and a compliant workload can become non-compliant after a routing, schema, or placement change. This paper presents Federated Compliance Control (FCC), a security architecture for multi-cluster environments that combines common control objectives, cluster-local enforcement, policy-as-code evaluation, evidence ledgers, and bounded remediation. FCC treats compliance as a continuously measured property of a resource graph rather than as a periodic checklist. A prototype across three clusters and four workload classes shows that FCC reduces unresolved policy drift by 48.4%, lowers mean critical exposure time by 65.6%, and increases audit evidence completeness from 61% to 94% compared with manual compliance operations, while keeping p95 gateway latency overhead below 7%. These results suggest that multi-cluster security requires coordinated policy reconciliation rather than either centralized control or independent cluster administration alone.