Multitenancy

Multitenancy is an architecture that serves multiple tenants through a single instance of a software application. The system isolates the data of each tenant and keeps it inaccessible to other tenants.

Multitenancy can be implemented at various levels, from a shared database schema to fully isolated environments with separate databases and resources. The level of isolation depends on the software provider’s requirements and tenant preferences.

Multitenancy provides several strategic benefits. By centralizing application maintenance, updates, and monitoring in a unified instance, you reduce operational overhead and simplify system management. Shared resource use lowers infrastructure costs, and the scalable architecture supports fluctuating workloads and growing user bases without proportional increases in resource consumption.

These advantages make multitenancy a foundational model for cloud-native solutions, especially in software-as-a-service (SaaS) models, where cost optimization, simplified management, and elastic scaling are essential.

However, multitenancy also presents challenges, such as data security and customization limitations. Data privacy and security are critical because a breach can affect multiple tenants. Tenants also have limited ability to customize the software, because changes can impact other users in the shared environment.

Pega Diagnostic Center and Pega Academy challenge instances using multitenant architecture.

Pega Platform™ supports multiple tenancy models, each designed to address specific business requirements and operational constraints. Selecting an appropriate tenancy model requires careful evaluation of five critical factors: cost efficiency, customization capabilities, tenant isolation, maintenance overhead, and scalability requirements.

The single-tenant model provides maximum isolation and customization flexibility. It is ideal for organizations that require strict compliance or extensive customization. However, single-tenant deployments require higher infrastructure costs and more complex maintenance procedures. Use this model when data sovereignty, regulatory compliance, or unique business processes demand complete application isolation.

The multitenant model optimizes cost efficiency and scalability by sharing infrastructure resources across multiple tenants. Pega Platform maintains strict data isolation through its tenant-safe database architecture. This model reduces operational overhead and supports rapid scaling. Use this model when cost optimization and standardized processes are priorities. Shared infrastructure enables efficient resource utilization while maintaining security boundaries between tenants.

The hybrid tenancy model combines elements of both approaches to support complex enterprise requirements. This model provides flexibility in deployment strategies. Organizations can maintain dedicated resources for critical workloads and use shared infrastructure for standard operations. Hybrid approaches are valuable when compliance requirements or performance needs vary across business units.

Hybrid tenancy differs from multitenancy by combining elements of single-tenancy and multitenancy to balance resource efficiency and customization. Hybrid tenancy is useful when organizations have distinct requirements but want to benefit from shared infrastructure.

Technically, hybrid tenancy is a cloud computing architecture that combines the isolation of single tenancy with the cost-effectiveness and scalability of multitenancy. In a hybrid tenancy setup, each organization operates in its own private cloud environment. The organization can extensively customize and configure this environment to meet specific business needs, which provides greater control over application performance, security policies, and compliance.

Despite this customization, multiple organizations share the underlying infrastructure. This shared infrastructure supports dynamic resource allocation based on demand, which optimizes costs and improves scalability. Hybrid tenancy enables organizations to create tailored computing environments while benefiting from the efficiencies of a shared platform.

Pega Cloud® uses hybrid tenancy architecture.

The following diagram shows the relationship of hybrid tenancy in the following environments: Infrastructure as a service (IaaS), platform as a service (PaaS), and SaaS:

• Infrastructure as a service (IaaS) provides computing infrastructure, storage, network, and security as on-demand services.
• Platform as a service (PaaS) provides a platform for developers to build and deploy applications. PaaS providers manage infrastructure, operating systems, and middleware, while developers focus on application development.
• Software as a service (SaaS) delivers software through a central host that users access by using a client, such as a web browser. SaaS enables multiple users across various locations to access the same application, which supports collaboration regardless of physical location.

Pega Cloud is a SaaS offering that includes infrastructure services, platform services, and application software accessible by using a browser.

Shelter-as-a-service analogy

The following analogy describes the SaaS model by comparing it to types of housing:

• On-premises is like owning a house. You manage monitoring, security, maintenance, repairs, utilities, and furniture.
• IaaS is like owning a condominium. You pay association fees, but still manage interior maintenance, utilities, and furniture.
• PaaS is like renting an apartment. You pay rent and manage furniture and cleaning.
• SaaS is like staying in a hotel. The hotel manages maintenance, upgrades, and availability.

When evaluating tenancy models, Lead System Architects should consider the following weighted criteria:

Cost efficiency encompasses both initial deployment costs and ongoing operational expenses. Multitenant models typically provide the highest cost efficiency through resource sharing, while single-tenant models require dedicated infrastructure investments. Hybrid models offer cost optimization opportunities through selective resource sharing.

Customization requirements determine the extent to which tenants can modify system behavior, user interfaces, and business processes. Single-tenant models provide unlimited customization capabilities, while multitenant environments require a careful balance between customization flexibility and system maintainability.

Isolation needs address security, compliance, and performance requirements. Single-tenant models provide complete isolation, multitenant models implement logical isolation through architectural controls, and hybrid models offer configurable isolation levels based on specific requirements.

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