Deploy as Multitenant SaaS Application

This guide explains how to deploy CAP multitenant SaaS applications to SAP BTP Cloud Foundry environment, and how SaaS Customers would subscribe to them.

• Intro & Overview
• Procedure
• Add MTX
• Build & Deploy
• Subscribe
• Behind the Scenes
• Appendix — Configuration
  • Configuring Job Queue Size
  • SaaS Service Dependencies

Intro & Overview

Software-as-a-Service (SaaS) solutions are deployed once by a SaaS provider, and then used by multiple SaaS customers subscribing to the software.

SaaS applications need to register with the SaaS Provisioning Service to handle subscribe and unsubscribe events. In contrast to single-tenant deployments, databases or other tenant-specific resources aren’t created and bootstrapped upon deployment, but upon subscription per tenant.

CAP includes the MTX services, which provide out-of-the-box handlers for subscribe/unsubscribe events, with automatic creation of SAP HANA database containers or SAP Event Mesh instances.

If everything is set up, the following graphic shows what’s happening when a user subscribes to a SaaS application:

1. The SaaS Provisioning Service sends a subscribe event to the CAP application.
2. The CAP application delegates the request to the MTX services.
3. The MTX services use Service Manager to create the database tenant.
4. The CAP Application connects to this tenant at runtime using Service Manager.

Procedure

The detailed procedure is described in the Deploy to Cloud Foundry guide. To start with this guide, you fulfill all Prerequisites and went through Prepare for Production, or instead run this command to fast-forward:

cds add hana,xsuaa,approuter,mta --for production

Add MTX

To enable MTX services for your project, run the following command:

cds add mtx --for production

This modifies the modules and resources in mta.yaml for multitenant deployment.

Learn more about MTX services.

Build & Deploy

You know the build and deploy steps from the Deploy to Cloud Foundry guide.

mbt build -t gen --mtar mta.tar

Learn more about Build & Assemble

cf deploy gen/mta.tar

Learn more about Deploy to Cloud Foundry.

Subscribe

Create a BTP subaccount to subscribe to your deployed application. This subaccount has to be in the same region, for example, us10.

In your subscriber account go to Instances and Subscription and select Create.

Select bookshop and use the only available plan default.

Go to Application.

As you can see, your route doesn’t exist yet. You need to create and map it first.

Leave the window open. You need the information to create the route.

Switch to your provider account and go to your space → Routes

Click New Route

Use the broken route to fill the fields. For the following explanations let’s use this route as example: https://my-account.cfapps.acme.com

• As Domain, use the part that usually starts with cfapps… and ends with .com

  In our example, the domain is: cfapps.acme.com

• As Host Name, use the part between https:// and .cfapps

  In our example, host name is: my-account

• Click Save

You can now see the route is created but not mapped yet (none).

Click Map Route

Select bookshop, which is the App Router application we just deployed, and save.

You’ve successfully created the route for your subscribed bookshop multitenant application. Refresh the browser tab of the bookshop application and log in.

Behind the Scenes

With adding the MTX services, your project configuration is adapted at all relevant places. Configuration and dependencies are added to your package.json and an xs-security.json containing MTX-specific scopes and roles is created.

For the MTA deployment service dependencies are added to the mta.yaml file. Each SaaS application will have bindings to at least three SAP BTP service instances.

If you’re interested, use version control to spot the exact changes.

Appendix — Configuration

Configuring Job Queue Size

The job queue size can be modified to allow for more concurrently running operations. For instance, its size could be increased to 10 by adding

"mtx": {
  "jobqueue": {
    "size": 10
  }
}

to your package.json or .cdsrc.json, or by setting the environment variable CDS_MTX_JOBQUEUE_SIZE=10.

SaaS Service Dependencies

If you require SAP reuse services, that need subscriptions, use cds.mtx.dependencies in your package.json and pass an array of their xsappnames.

The SaaS Provisioning service (getDependencies handler) needs this information.

"mtx": {
  "dependencies": ["xsappname-1", "xsappname-2"]
}