Models Related to Multi-Tenant

Figure 1 shows the models related to multi-tenant.

Figure 1 Models related to multi-tenant

Table 1 describes the concepts involved in Figure 1.

**Table 1** Concepts involved
Concept	Description
User	A natural person who has a name and password and uses the big data platform. Figure 1 shows three different users: user A, user B, and user C.
Role	A role is a carrier of one or more rights. Rights are assigned to specific objects, for example, access rights for the /tenant directory in HDFS. Figure 1 shows four roles: role t1, role t2, role t3, and role Manager_tenant. Roles t1, t2, and t3 are automatically generated when tenants are created. The role names are the same as the tenant names. That is, roles t1, t2, and t3 map to tenants t1, t2, and t3. Role names and tenant names need to be used together. Role Manager_tenant is the role of the cluster and cannot be used separately.
Tenant	A tenant is a resource set divided from a big data cluster. Multi-tenant refers to multiple tenants. The source sets further divided in a tenant are called sub-tenants. Figure 1 shows three tenants: tenant t1, tenant t2, and tenant t3.
Resource	Computing resources include CPUs and memory. The computing resources of a tenant are divided from the total computing resources of the cluster. One tenant cannot occupy the computing resources of another tenant. In Figure 1, computing resources 1, 2, and 3 are divided from the cluster's computing resources by tenants t1, t2, and t3. Storage resources include disks and third-party storage systems. The storage resources of a tenant are divided from the total storage resources of the cluster. One tenant cannot occupy the storage resources of another tenant. In Figure 1, storage resources 1, 2, and 3 are divided from the cluster's storage resources by tenants t1, t2, and t3.

If a user wants to use a tenant's resources or add or delete a sub-tenant from a tenant, the user needs to be bound to both the tenant role and role Manager_tenant. Table 2 shows the roles bound to each user in Table 2.

**Table 2** Roles bound to each user
User	Role	Rights
User A	Role t1 Role t2 Role Manager_tenant	Uses the resources of tenants t1 and t2. Adds or deletes sub-tenants for tenants t1 and t2.
User B	Role t3 Role Manager_tenant	Uses the resources of tenant t3. Adds or deletes sub-tenants for tenant t3.
User C	Role t1 Role Manager_tenant	Uses the resources of tenant t1. Adds or deletes sub-tenants for tenant t1.

One user can be bound to multiple roles, and one role can be bound to multiple users. Users are associated with tenants by binding themselves to the tenants. For this reason, tenants and users are in many-to-many relationship. One user can use the resources of multiple tenants, and multiple users can use the resources of a tenant. In Figure 1, user A uses the resources of tenants t1 and t2, and users A and C uses the resources of tenant t1.

The parent tenant, sub-tenant, level-1 tenants, and level-2 tenants are designed for multi-tenant service scenarios. Pay attention to the differences between these concepts and those of leaf tenant and non-leaf tenant on FusionInsight Manager.

Level-1 tenant: The name is determined by the tenant's level. For example, the created tenant is a level-1 tenant whose sub-tenant is a level-2 tenant.
Parent tenant and sub-tenant: indicates the hierarchical relationship between tenants.
Non-leaf tenant resource: indicates the tenant resource type selected during tenant creation, which can be used to create sub-tenants.
Leaf tenant resource: indicates the tenant resource type selected during tenant creation, which cannot be used to create sub-tenants.

Multi-Tenant Platform

Tenant is a core concept of the FusionInsight big data platform. It assists in transforming the big data platform from the user-centered platform to the multi-tenant-centered platform to better cope with the multi-tenant application environment of modern enterprises.

Figure 2 User-centered platform and multi-tenant-centered platform

On the user-centered big data platform, users can directly access and use all resources and services.

However, some cluster resources may not be used, lowering resource utilization.
The data of different users may be stored together, decreasing data security.

On the multi-tenant-centered big data platform, users use required resources and services by accessing the tenants.

Resources are allocated and scheduled based on application requirements and used based on tenants, increasing resource utilization.
Users can access the resources of tenants only after being assigned roles, enhancing access security.
The data of tenants is isolated, ensuring data security.

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