Confused by buzzwords? You’re not alone.
EXPLAINED is a new explainer series for people who work with technology – but don’t want marketing fluff or academic theory.
We break down complex digital topics clearly and practically: what they mean, why they matter, and how they work in the real world.
Multi-tenancy sounds like something your landlord worries about.
In software, however, a tenant is simply a customer, organisation or group using a service. Multi-tenancy means that several of those tenants use the same underlying software and hardware, while each one is kept in its own separate space.
Think of a block of flats.
Everyone shares the foundations, the roof, the corridors, the mains utilities (water/gas/electricity) and the people responsible for maintaining the building. But every household has its own front door, its own key, its own rooms and its own belongings.
Multi-tenant software works in much the same way. It allows organisations to share servers, computing power, software updates and administration, without sharing accounts, permissions or private data.
The opposite model is single-tenancy. Single-tenancy is a freehold detached house… and power station and water treatment plant and road maintenance team and…. You have full control and responsibility for everything – a nice garden to run around in, but you also get to fix your own boiler, mow your own lawn, pay for your own roofing repairs, and run your own utility companies.
In software terms, that can mean another virtual machine, another database, another filesystem, another message bus, another cache, another application stack – all duplicated for every organisation you serve. Multiply that by hundreds or thousands of customers and the inefficiency becomes obvious.
Crucially, multi-tenancy does not mean giving control to somebody else or moving everything into a public cloud. You can still run software on your own premises, on infrastructure you control, in your own private cloud, as a highly efficient multi-tenant service.
The point? Share the machinery, not the data.
What is actually shared?
The easiest way to understand multi-tenancy is to separate the machinery from the contents.
The machinery includes the servers that provide computing power, the software running on them, the monitoring systems and the work needed to maintain and update everything.
The contents belong to the tenants: their users, documents, permissions and private settings.
A well-designed multi-tenant system maintains a strong boundary between the two. It knows which tenant every request belongs to and ensures that users can access only the information and functions available within their own space.
Sharing the machinery doesn’t mean sharing what is inside it.
Why use multi-tenancy?
Running a separate software deployment for every customer can be expensive and difficult to manage, and in many cases is unnecessary.
Imagine a hosting provider serving a thousand organisations. With single-tenancy, it might need to maintain a thousand separate deployments. Each one must be monitored, updated, backed up and secured.
With multi-tenancy, much of that work can be done centrally. Computing capacity can be shared rather than sitting unused, updates can be rolled out consistently, and administrators have fewer separate systems to watch.
The same principle can apply inside a large organisation. Different departments, subsidiaries or schools can use one carefully managed platform instead of maintaining many unrelated installations.
What could go wrong?
Sharing infrastructure creates its own engineering challenges.
One tenant must never be able to access another tenant’s data. A particularly busy tenant should not be able to consume all the available computing power. A fault affecting one part of the service should be prevented from spreading unnecessarily.
This is sometimes called the “noisy neighbour” problem. Living next to a party is annoying, having the party knock out the electricity for the entire building is worse.
Good multi-tenant systems address this through isolation, access controls, resource limits, monitoring and careful distribution of work. Multi-tenancy is therefore not automatically secure or insecure. It depends on the architecture and on how the service is configured.
Why should you care?
Because dedicated installations for everyone is a luxury that rarely survives contact with a budget.
If you’re a hosting provider with a thousand customers, running a thousand separate installations means a thousand things to patch, update, monitor, and secure. When a security fix lands, you apply it a thousand times. Multi-tenancy means you apply it once, and every tenant is protected the same afternoon.
Even inside a single large organisation the same logic applies: one well-managed deployment serving many departments, subsidiaries, or schools beats a sprawl of half-forgotten servers – any one of which could be the unpatched machine an attacker finds first.
How Collabora Online does it
Collabora Online was built with hosting providers in mind, and multi-tenancy runs right through the architecture.
A single Collabora Online installation can serve multiple hosts and integrations at the same time – Sharepoint, WordPress, Seafile, Drupal, Nextcloud, ownCloud, OpenCloud, Moodle, EGroupware… or any other WOPI-based integration – for many different customers at once. Tenants are defined in alias groups, each one an allow-list of who may connect, and they can be added or removed dynamically, without restarting the server. New customer? Just add a new front door, and everything else works behind the scenes. No downtime.
Two key design decisions (amongst many) do the heavy lifting on isolation:
First, Collabora Online doesn’t store your documents. Each tenant’s documents live in the tenant’s own storage – their EFSS, their infrastructure – and are only fetched for editing and returned when saved. The building services are shared, but your filing cabinets never leaves your flat.
Second, every open document is handled in its own separate, sandboxed process on the server. Documents from different tenants – or even the same tenant – are never mixed together in one process. In many respects Collabora Online operates more like a prison than a block of flats, with well built walls and multiple layers of security.
What about big deployments?
Tools like copy-on-write make scaling software pretty magical, but even then, you might have a few problems if 100,000 people need to move into your apartment complex overnight. That’s when it’s time to call in the urban planners.
That’s why for large multi-tenant installations, Collabora Online runs using Kubernetes, where the Collabora Online Controller makes sure every user editing a given document is routed to the same place, and shifts documents away from busy servers onto quieter ones. Capacity can be scaled up for the Monday-morning rush and back down for the weekend – which is exactly the economics that make multi-tenancy attractive in the first place: shared infrastructure, efficiently used.
That also answers the classic multi-tenancy worry about “noisy neighbours” – one tenant’s busy day slowing down everyone else. Monitoring and rebalancing exist precisely so that your neighbour’s party stays on their side of the wall.
One size doesn't have to fit all
Here’s the part a good explainer shouldn’t skip: multi-tenancy is a choice, not a requirement.
Some organisations – for compliance, sovereignty, or simply preference – want the detached house. Collabora Online is happy either way: the same software runs as a dedicated single-tenant installation on premise or your choice of hosted infrastructure, as a multi-tenant platform run by a hosting provider, or anything in between. And because it’s open source and self-hostable, the decision stays where it belongs: with you.
So what’s the point?
Done well, multi-tenancy means lower costs, gives consistent updates for everyone, and infrastructure that is watched by professionals rather than forgotten in a cupboard. Done with Collabora Online, it means documents stay in each tenant’s own storage, are processed in isolation, and the whole thing scales from one team to millions of users.
Host documents for one tenant – or a thousand.
Whether you’re a hosting provider building a document-editing offering for your customers, or an organisation that wants one deployment to serve every department, Collabora Online gives you secure, scalable, multi-tenant document editing on infrastructure you control.
Build your efficient multi-tenant document-editing service today with Collabora Online.
