Web farm deployment
Definition
Running one application across several servers behind a load balancer, so consecutive requests from the same user may be handled by different machines.
Web farms break anything that assumes a request lands where the previous one did. Document viewers are unusually exposed to this, because opening a document creates server-side state — the rendered pages — that later requests expect to find.
The naive fix is sticky sessions, pinning a user to one node. It works until that node is drained for deployment, at which point every open document in flight fails at once.
The durable fix is a shared render cache. Any node can serve a page for a session any other node opened, so nodes become interchangeable and rolling deployments stop being an event.
In Doconut
Web farm and distributed deployment are supported through a shared render cache, so a session opened on one node stays readable from another. Cached page images are derived copies of sensitive documents — give the cache an eviction policy that matches your retention rules.
Related terms
Opaque session token
An identifier that carries no meaning to whoever holds it — it references server-side state rather than describing it, so a client cannot read it, modify it, or guess a neighbouring value.
Server-side document rendering
Converting a document into page images on the server, so the browser displays rendered pages rather than parsing the original file itself.
Air-gapped deployment
Running software in an environment with no network route to the internet, so every dependency it needs must already be inside the boundary.