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Understanding dependencies
↩ Servers
A dependency records that one thing relies on another — this service needs that database, this site needs that link. Once recorded, JOATOS can answer what an outage actually costs.
Dependencies aren't a server feature: the same Dependencies tab appears on devices, servers, services and sites.
Adding one
On the Dependencies tab, use Add dependency and search for what this thing depends on. You can link to:
- Sites, devices, servers and services
- Server features — a specific role or feature on a server, rather than the whole machine
That last one matters: a machine can host several things, and "the web app depends on this server" is less useful than "the web app depends on this server's database role".
Reading it
Each item shows:
- Upstream — what this depends on. If these go, this goes.
- Downstream — what depends on this. If this goes, these go.
Impact takes it further, following the chain rather than stopping at the first hop — so you can see everything affected, not only the immediate neighbours.
Where it pays off
- During an outage, downstream answers "who else is affected, and who do I need to tell?"
- Before a change, upstream and impact are what turn a change's affected items into a real blast radius — see Raising a change.
- On the status page, live dependency impact understands redundancy, so a redundant path doesn't report as an outage.
Notes & tips
- Record dependencies as you discover them during incidents. Trying to map everything in one sitting rarely finishes.
- Link to a server feature rather than a server when only part of the machine matters.