What Is Multi-Tenant Architecture? Ultimate Guide

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Multi-tenant architecture, more commonly referred to as multi-tenancy, is a software architecture where multiple instances of an application run on the same physical server. The same server is then responsible for serving multiple tenants simultaneously.

This type of build allows companies to allocate a single infrastructure to several end users, rather than individually managing the maintenance and updates of multiple environments.

This article will help you understand how multi-tenancy works as well as its advantages and disadvantages and the various types of databases used in them.

Table of Contents

• How Multi-Tenancy Works
• Advantages of Multi-Tenancy
• Disadvantages of Multi-Tenancy
• 3 Main Types of Multi-Tenant Databases
• 3 Multi-Tenant Architecture Examples
• Choosing Between Multi-Tenant and Single-Tenant Architecture

How Multi-Tenancy Works

The term “tenant” is used to describe the group of users or applications that share access to the same hardware resources. In a multi-tenant architecture, all users share access to the same infrastructure resources that could facilitate collaborative work such as memory, network controller, and access to system resources.

It’s used often in cloud computing, enabling service providers like Amazon Web Services, Microsoft Azure, and Google Cloud to offer a more affordable shared-tenancy option on the public cloud. However, it can also be utilized by software-as-a-service (SaaS) companies or companies with internal software that needs to be distributed to employees in various departments and physical locations.

Multi-tenant architecture works by utilizing virtual machines (VMs). On the same physical server, they’re able to create multiple VMs that all share the same hardware but operate as separate computers in complete independence from one another. This guarantees the user’s security and privacy, especially if the cloud environment is shared with foreign individuals and entities.

This is the opposite of single-tenancy, in which the server runs one instance of the operating system and one application. This one application could be something simple like file and print apps, complex like web or application servers, or mission-critical such as a database.

What is the Difference Between a Multi-Tenant and Single-Tenant Architecture?

Single-tenancy is largely seen as the “deluxe” option, in that a client operates in a solely dedicated environment. In a multi-tenant environment, each customer shares the software application along with a single database, so multiple people from the same company can access the database. Still, even in multi-tenancy, each tenant is isolated from other tenants.

The chief advantage of multi-tenant hosting is that it is less expensive. Resource pooling greatly reduces the cost since companies only pay for what they need. And since multi-tenancy is part of a SaaS provider, companies are not paying for on-premises hardware.

Functions like system monitoring and servicing the deployment become shared among all of the customers, which makes it less expensive as the cost is spread around.

Advantages of Multi-Tenancy

The multi-tenant model is used by numerous reputable cloud providers because it’s sought after by users and clients in a wide variety of fields. The following are a handful of multi-tenancy’s most notable advantages.

Reduced Costs

Multi-tenant cloud architecture models tend to be more cost-efficient than their single-tenant counterparts. This is because most service providers follow a pay-as-you-go pricing model, where companies don’t have to pay for the entirety of the cloud environment if they’re not occupying or using it.

The cost of a single environment is, instead, shared by all of the tenants. This not only includes the costs of the hardware but also all of the software and maintenance work going into keeping the environment running.

It’s Highly Scalable

Working with cloud service providers is highly scalable. Companies don’t need to plan the purchase and onward maintenance of an extension to their environments; they simply request a larger offering.

This also goes the other way around. If companies need to scale down operations, they’re not left with unused server space that still needs maintenance. The down-scaling process is just as easy and seamless as upscaling.

Maintenance-Free

With multi-tenancy, companies are buying into a done-for-you product that already includes all of the necessary maintenance work for its software and hardware components, ranging from software updates and patches to ensuring availability, backup, and uptime.

All of the labor needed to maintain the environment is included in the contract and shared with other tenants.

Improved Security and Privacy

While single-tenant architecture offers more advanced security and privacy capabilities, multi-tenancy is still considerably more secure than relying on other methods of sharing data and software resources among a pool of users.

The security and privacy of the data processed on the multi-tenant cloud are guaranteed and maintained by the service provider. Additionally, having everything in the same environment allows for effective threat and intruder detection and prevention, compared to spread-apart resources.

Backup and Data Restoration

Some multi-tenancy providers include a built-in data backup and recovery system that allows businesses to manage data reliably. When configuring for regular backup, it’s best to implement an option offered by service providers themselves, as they tend to be more familiar with the best way to handle data on their cloud.

Disadvantages of Multi-Tenancy

Before switching to a multi-tenant cloud offering, it’s just as important to be aware of the limitations and drawbacks of using this type of architecture. The following are a handful of multi-tenancy’s most notable disadvantages.

Lacks Customizability

Multi-tenant architecture is considered an off-the-shelf product, and since businesses will share software and hardware resources with multiple other customers, they’re limited in the changes they can implement.

This reduction in control can hinder business operations and a team’s progress online, as certain features may be missing while others are in the way.

Competing for Limited Resources

While most service providers put in their best efforts to keep the resources well-divided between various users, this isn’t always guaranteed. With multiple customers using the same system resources and computing power, companies might start suffering from “noisy neighbor” syndrome, where they can’t access the resources they need, and operations slow down.

Luckily, there are provisioning protocols that can be put in place to reduce the likelihood of this occurring. This includes load balances and elastic cloud computing.

Migration Difficulty

While multi-tenant architectures are easy to adapt, they can be hard to leave. Migrating data from a multi-tenant environment to any other type of environment can be a challenge because personal data is scattered all over the shared cloud, wherever there’s room for it.

Security and Privacy Challenges

Even with careful provisioning protocols and partitioning between the various VMs, companies are still sharing hardware with other users who aren’t authorized to access their part of the cloud. Normally, this isn’t a problem. However, malicious individuals could try to take advantage of such a vulnerability.

It could also occur unintentionally. Instances of data corruption have the possibility to spread through the entirety of the software instance. A malicious attack that was targeting other users on the shared public cloud may end up reaching a different user and their sensitive data.

Global Problems and Downtime

By outsourcing data and operations to an external cloud managed by a third-party service provider, companies risk losing access to critical data and information in the case of a technical error. Also, cloud environments are susceptible to downtime; although, it’s minimal with the top providers.

3 Main Types of Multi-Tenant Databases

In a multi-tenant environment, multiple customers share the same application, in the same operating environment, on the same hardware, and with the same storage mechanism and database.

This is how Salesforce and every other SaaS operator run. Every tenant is a customer or user who has common access and specific privileges in the software instance.

The database, however, is another matter. There are three ways to architect a database in a multi-tenant system.

1. Shared Database, Shared Schema

The simplest and most straightforward application of a multi-tenant architecture involves the sharing of multiple schemas for the same database. A schema refers to the construction of a database, and it’s usually made out of database tables that relate to one another.

The tables are used to manage the simultaneous access to the same dataset, like when two people are attempting to manipulate the same table or data entry at the same time.

This database architecture is the cheapest and easiest to manage for the host. Additionally, it’s highly scalable to accommodate more tenants.

2. Shared Database, Multiple Schemas

Sharing a single database through multiple schemas is another way to manage a multi-tenant environment. With multiple schemas inside a single database, a business can have sub-databases that can divide datasets without having to set up multiple separate databases.

Unlike shared schemas, this approach allows each schema to operate in complete isolation from the rest of the database. This is suitable for applying different rules and regulations and various datasets to respect international data management laws, for example.

This approach is, however, more costly, as each individual division of the database requires its own administrative efforts. Not to mention, the scalability of the environment is somewhat limited.

3. Multiple Databases, Multiple Schemas

The multiple database approach takes the separations of schemas and datasets a step further. Clients can have different divisions of data on completely separate databases, such as segregating for sales, customers, and employees, or dividing by region.

The host would have to install the application separately for each client on their database, which adds a layer of complexity to management, maintenance, and scalability to this type of multi-tenancy deployment as well as the costs.

On the flip side, this approach to multi-tenancy affords the clients a higher level of data isolation, improving the privacy and security of their data.

3 Multi-Tenant Architecture Examples

In utilizing virtual systems in VMs, a single system would have to handle numerous instances, all running several versions or even different operating systems. Also, each one of those instances has to run its own application along with its associated database.

When implemented into a multi-tenant architecture, all of the instances within a VM have to share the same base operating system, applications, and database access. In fact, this is the same model that’s used in infrastructure-as-a-service (IaaS), platform-as-a-service (PaaS), and SaaS offerings.

Since IaaS, PaaS, and SaaS rely on resource sharing, from hardware to software, they use multi-tenancy in running their environment. This also enables them to create high-scalability offers for customers.

That’s how 50 people from the same company can work on Salesforce CRM. Similarly, a SAP system is composed of a database back end and web application servers that host web services in a highly scalable manner. The web services that make up the SaaS app are exposed to different customers via different domain names. Scaling is achieved by starting more services.

The following are three examples of a multi-tenancy architecture:

1. URL-Based SaaS

URL-based SaaS, also known as web-based SaaS, is a method of delivering software service over the internet that can be accessed through a dedicated URL. This is an alternative approach to the installation of a desktop app keeping it up to date on the client’s front. This approach to SaaS is easier to do and allows for less complex software and hardware management.

Using a URL as the primary method of SaaS deployment is also easier for the host service provider, as they’d only have to manage a single domain and database. Each client would have a specific subdomain to access their part of the service, like subdomain1.maindomain.com, subdomain2.maindomain.com, and so on.

For the host, data management and security are handled at the applications level, rather than individually for each client. Many SaaS providers operate using this model, especially those that put a web app interface between the user and the primary database. Furthermore, the host can set up different Domain Name System (DNS) entries depending on the customer’s needs and how they’d like their traffic to be filtered.

The difference in URL allows the clients some level of customization. Of course, it’s limited since the architecture is still multi-tenant, but clients can implement their own local testing or even changes to the user interface (UI) and user experience (UX).

2. Multi-Tenant SaaS

In a multi-tenant SaaS structure, multiple customers are made to share the same software and hardware in order to cut costs and management efforts. Usually, this is done through the sharing of a single instance of the software along with its supporting data and information.

This approach tends to be slightly more complex for the host due to the number of databases and schemas accessed by clients, along with the restrictions they need to put in place at the database level. However, this is still how many SaaS apps operate as it often allows for more direct interaction with the database, cutting back on lag and wait times.

Another benefit to utilizing a multi-tenant approach to SaaS applications is the increase in computing capacity per customer. Also, individual customers won’t have to worry about server and processing power capacities, but simply access the system and pay according to the resources they use.

Similarly to other approaches to multi-tenancy, this reduces the customization options for customers. Dedicated upgrades tend to be time-consuming and more complex to implement without negatively affecting the rest of the environment for the remainder of the customers.

3. Virtualization-Based SaaS

Virtualization-based SaaS, also known as containerized SaaS, is the most complex SaaS setup approach.

Through virtualization, the SaaS provider would be creating an entirely separate virtual version of all resources needed to run the software service, including the servers, desktop, operating system files, storage, and network access. Those would have to co-exist on the same hardware infrastructure without interacting with or influencing one other.

When it comes to implementing a multi-tenant architecture alongside virtualization, regular interaction between the containers, applications, and databases is essential. This is what makes it incredibly complex to maintain. Such structures tend to require specialized container orchestration tools to manage the communication and influence between individual containers, like Kubernetes and Docker.

One example of a virtualized SaaS environment is Amazon Web Services, where Amazon hosts a number of platforms and software that are available to a large number of business clients and users.

This approach to SaaS allows for more customizability for each individual user. Also, scalability is instantaneous and doesn’t sacrifice the software’s capabilities or limit access to the client’s own dataset.

Choosing Between Multi-Tenant and Single-Tenant Architecture

Choosing between single- and multi-tenant often comes down to a choice of on-premises versus the cloud. For instance, there is no single-tenant version of Salesforce, and in contrast, major databases tend to be single-tenant so as to have full access to resources.

Security of data is clearly a concern, but that falls primarily on the shoulders of SaaS providers. They are the ones responsible for monitoring tenants and making sure there is no data bleed from one customer to another, and they do a good job of it.

“If the cost to the end user is acceptable regardless of model, multi-tenant versus single tenant is really just a trade-off between change control and acceptable security risk,” said Morey Haber, chief security officer at BeyondTrust and member of the Forbes Technology Council. “If you always want to be on the latest version, either model is acceptable. You just have to manage the change control yourself.”

The client’s primary responsibility for securing the data falls to the client’s device. All of the major SaaS providers do offer two-factor authentication to secure logins. After that, it’s up to the client to maintain the security of the endpoint device.

Multi-tenancy is at the heart of cloud computing. It is designed to help scale up thousands of users both within an enterprise and externally as companies interact and do business. Whether it’s a Salesforce account or an app the company built on AWS for customers, multi-tenancy can scale through public and private cloud and provide true economies of scale.

Implementing a Multi-Tenant Architecture

Multi-tenant architecture is an approach to data structuring, usually in a cloud environment, that allows multiple users to access and share the software and hardware resources of the environment. This is done with complete separation between individual customer entities to ensure the privacy and security of their data.

It’s more cost-efficient for both the service host and the customer. It’s also highly scalable and guarantees access to the latest version of the software and hardware of the service. However, it offers fewer customization opportunities, and the resources may be put under strain if not managed properly by the host.

Choosing between a multi-tenant and a single-tenant architecture depends on numerous factors, ranging from cost and privacy and security needs to availability and the type of service in use.