Shared dependency without redundancy

errorshared-dependency-without-redundancy

The design requires redundant discovery, but this DNS or coordination service, which everything depends on, runs on a single provider or a single replica. Its failure is the whole system's failure.

Severity: error
Selects: every node of kind dns or coordination-service
Components in scope: 52

What it checks

It looks at every node of kind dns or coordination-service, and fires when:

— all of these hold:
— the design requirement `availability.discoveryRedundant` is true
— any of these hold:
— the node's `redundantProviders` is false
— the node's `replicated` is false

Message

Shared dependency '{{node.id}}' is not redundant, but the design requires redundant discovery.

{{node.id}} style paths are filled in from the node, the edge or the design the finding is about.

Applies to · 52 components

Coordination service coordination-service DNS dns

Tripped by · 17

Reference designs whose broken twin names this rule in its header. The gate reads the same header, and fails when a rule no design trips.

booking-searchreference cloudflare-edgereference distributed-message-queuereference github-mysqlreference linkedin-kafkareference monzo-platformreference nearby-friendsreference netflix-streamingreference object-storagereference robinhood-tradingreference shopify-flash-salereference spotify-playbackreference stack-overflowreference stripe-paymentsreference tinder-georeference unique-id-generatorreference zoom-videoreference

Source

1# yaml-language-server: $schema=../schema/rule.schema.json
2# The design requires redundant discovery, but a DNS or coordination service that every
3# component depends on has a single provider or a single replica.
4# Tripped by: designs/object-storage.broken.yaml
5schemaVersion: "1"
6type: "rule"
7id: "shared-dependency-without-redundancy"
8severity: "error"
9select:
10  node:
11    kind: ["dns", "coordination-service"]
12when:
13  all:
14    - requirement: "availability.discoveryRedundant"
15      equals: true
16    - any:
17        - prop: "redundantProviders"
18          equals: false
19        - prop: "replicated"
20          equals: false
21message: "Shared dependency '{{node.id}}' is not redundant, but the design requires redundant discovery."

The same page as markdown, for an agent: /catalogue/rules/shared-dependency-without-redundancy.md