A tenancy model describes how computing resources are isolated or shared between customers in a hosted environment. In a single-tenant setup, one customer gets dedicated infrastructure or a logically separate stack. In a multi-tenant setup, multiple customers share the same underlying platform, with software controls keeping their data, identities, and workloads separated.
This matters in cyber security because the tenancy model determines the blast radius of mistakes and attacks. Weak isolation can expose data, logs, or management functions across tenants, while stronger separation can reduce cross-customer risk but increase cost and operational complexity. Defenders assess tenancy when reviewing access control, segmentation, encryption, audit logging, and data residency. Attackers may target shared control planes, misconfigured permissions, or flaws in tenant isolation to move laterally or read another customer’s resources.