07-04-2023

Challenge the future

DelftUniversity ofTechnology

Enabling Multi-TenancyAn Industrial Experience Report

Cor-Paul Bezemer, Andy Zaidman, Bart Platzbeecker, Toine Hurkmans, Aad ‘t Hart

2Enabling Multi-Tenancy

Outline

• What is multi-tenancy?

• Converting single-tenant to multi-tenant

applications

• CodenameMT

• Lessons learned

3Enabling Multi-Tenancy

What is Multi-Tenancy?

vs.

4Enabling Multi-Tenancy

What is Multi-Tenancy?

vs.

A multi-tenant application lets customers (tenants)

share the same hardware resources, by offering them

one shared application and database instance, while allowing them to configure the application to fit

their needs as if it runs on a dedicated environment.

5Enabling Multi-Tenancy

Multi-Tenancy vs. Multi-User

• Tenant can span multiple users

• Tenants can have SLAs

• Tenants have more configurability options

6Enabling Multi-Tenancy

Benefits of Multi-Tenancy

• Lower number of application and database

instances

• Results in easier (& cheaper) deployment

• Requires high degree of configuration

• Higher utilization of hardware resources

• Results in lower hardware costs

• Lower deployment and hardware costs

• Results in the opportunity to offer a service at a

lower price

7Enabling Multi-Tenancy

Challenges of Multi-Tenancy

• Performance

• Scalability

• Security

• Zero-downtime

• Maintenance

• Configurability increases complexity

8Enabling Multi-Tenancy

Exact Codename and Multi-Tenancy

• Exact Codename: prototype of a Web 2.0

community

• Codename is currently single-tenant

• Why is multi-tenancy interesting for Codename?

• Allow rapid ‘deployment’ of different communities

• Install one instance, configure/maintain many

• Save on hardware resource costs

9Enabling Multi-Tenancy

A Multi-Tenant Codename Version

• Goal: Create a multi-tenant version of

Codename

• Requirements:

• Minor adjustments in existing code

• Let developers be (mostly) unaware of multi-

tenancy

• Clearly separate multi-tenant components

10Enabling Multi-Tenancy

11Enabling Multi-Tenancy

Codename Architecture

12Enabling Multi-Tenancy

CodenameMT: Authentication

• Add CodenameMT as a known party to the

existing single sign-on server

• Add TenantID to token (claim and User objects)

• Note: ‘original’ Codename authentication still in

place!

13Enabling Multi-Tenancy

CodenameMT: Configuration

• Layout style

• Adapt global.asax to load tenant-specific

masterpage/theme

• General configuration

• Stored in the database (handled by Data Access Layer)

• File I/O

• Load tenant-specific lists/entities

• Workflow - future work

14Enabling Multi-Tenancy

CodenameMT: Database

• Add TenantID to tables that contain tenant-specific

data

• Not all tables contain such data, e.g. the Countries table

• Add IsMultiTenant to data model

• Update Data Layer so that queries are aware of

TenantID

• Add TenantID to indexes where necessary

15Enabling Multi-Tenancy

Lessons Learned

• Lightweight reengineering approach

• Approx. 100 lines of code added to ~165K LOC

• Approx. 3 days of implementation were needed

• Layered architecture is important

• Fully transparent for the end-user

• End-user is unaware that the application is multi-tenant

• Little effect for the developer

16Enabling Multi-Tenancy

Future Work

• Performance monitoring/prediction

• Prototype in ‘ideal’ multi-tenant architecture

• Apply ideas to Exact Online

• “Can we predict a peak in performance, and

take appropriate scalability measures in time?”