Multi-Tenancy in SharePoint 2013 (part 1) - Managing Service Application Groups, Creating a Site Subscription

No discussion about service applications would be complete without digging into the multi-tenant capabilities that have been improved from SharePoint 2010. Under normal circumstances, the multi-tenant discussion usually pertains to hosted environments where a SharePoint farm is providing services to any number of different companies; but as you will see in this section, the concept of multi-tenancy applies directly to the enterprise as well.

Managing Service Application Groups

In SharePoint 2007, the walls of security and the isolation of data and services went along the lines of web application to site collections to webs. Beginning with SharePoint 2010, it became possible to create a new segregation layer of data and services between the application layer and the associated site collections. This segmentation is possible through the use of site subscriptions. Site subscriptions enable you to group together site collections that are part of the same web application. Site subscriptions are a logical group of site collections that can share settings (in the Subscription Settings database), features, and service data. Site subscriptions are identified with a subscription ID. The subscription ID is used to map services, features, and sites to tenants, and to partition service data by tenant. Note the following characteristics of site subscriptions:

• A site can be a member of only one site subscription at a time. This prevents any conflicts with licensing schemas.
• There is no Central Administration interface for managing site subscriptions. Management must be handled through PowerShell, including creating, managing, and removing sites from a site subscription.
• A site can only join a site subscription(s) in the same web application. Sites can’t join a site subscription(s) associated with other web applications.
• Site subscriptions can span multiple content databases.

Once you have a site subscription associated with site collections, the site collections can consume data from service applications. While this concept is not necessarily new, what is new is that some of these service applications can be provisioned such that their functions and data are kept separate from other site collections (tenants) that may be consuming that service application. SharePoint 2010 and 2013 refer to this type of service application as a partitioned service application. For instance, if Enterprise Search were provisioned as a partitioned service application and associated with two site subscriptions, then search results from subscription A would never be returned to subscription B. Note also that no changes or additions were made to the number of databases required to support this capability. SharePoint merely segments the content within the single database (see Figure 1).

FIGURE 1

Although non-partitioned service applications can be created with Central Administration or PowerShell, the latter is required to provision a partitioned service application. When creating a partitioned service application in PowerShell, you only need to add the –Partitioned or -PartitionMode switch depending on the service application.

Some service applications do not lend themselves to being partitioned, such as those that do not store user-specific data. Table 1 shows which service applications within SharePoint 2013 can be partitioned.

TABLE 1 SharePoint 2013 Service Application Partitioning

Another set of capabilities that was previously managed at the web application layer was Features. When a feature was installed and activated at a web application layer, it was automatically available for activation at the site collection level. Beginning with SharePoint 2010, you can group features together into what are called feature packs. Feature packs are logical groupings of features that are then made available for activation to a site subscription by an administrator of that site subscription.

SharePoint 2013 is smart enough to prevent the use of web parts that are part of a feature that is not part of a site subscription.

Once a site subscription is created and sites are associated with it, the sites are managed through a site template called a Tenant Administration site. It’s called this because a hosted customer (or department) is referred to as a tenant. The Tenant Administration site gives the tenant administrator full administrative rights over the site collections, including permissions to create new sites if self-service site creation is enabled.

Creating a Site Subscription

When you are ready to start working with SharePoint in the hosting mode, keep in mind that nearly all your system administration will be done through PowerShell, as these new features are not built into the SharePoint Central Administration console. This is true for creating site subscriptions, feature packs, and partitioned service applications, and provisioning Tenant Administration sites. The PowerShell cmdlet to create a new site subscription is as follows:

New-SPSiteSubscription

When building your site subscriptions, using variables for your commands enables them to be reused and/or nested within other cmdlets. For example, to create and view a new site subscription, use the following:

$SiteSub = New-SPSiteSubscription

Once you have the subscription, you need to get the site collection or site collections you want to add to the subscription into a variable.

To add a single site collection to a variable, use the following:

$TargetSite = get-spsite http://portal.contoso.com/sites/marketing

To instead add all site collections within a web application to a variable, use this:

$TargetSite = Get-SPWebApplication http://portal.contoso.com | Get-SPSite

Now that you have your site collection(s) in a variable, use the following to add their subscription:

$TargetSite | ForEach-Object{Set-SPSite -Identity $_ -SiteSubscription $SiteSub}

To view all the site collections that are now part of the site subscription, just type the name of the variable:

(Get-spsitesubscription $SiteSub).sites

From here you could create the Tenant Administration site using the PowerShell cmdlet new-spsite, identifying the site template as tenantadmin#0:

New-spsite –url http://portal.contoso.com/sites/tasite -template "tenantadmin#0" 
–owneralias domain\username –sitesubscription $SiteSub

Another benefit to site subscriptions is that usage analysis data and logging data are also segmented, like the user data. This enables the IT pro to troubleshoot and debug based on a specific site subscription. In addition, segmenting the usage data enables a hosting company or enterprise that’s using a charge-back model for IT services to charge according to usage based on data, processes, or the number of users.