Stateful node without zone redundancy

errorstateful-node-without-zone-redundancy

A stateful compute node pinned to exactly one availability zone disappears with that zone, and its state goes with it. Nodes inside a cell are exempt, because there the cell is deliberately single-zone and redundancy comes from the other cells.

Severity: error
Selects: every node in category compute
Components in scope: 648

What it checks

It looks at every node in category compute, and fires when:

— all of these hold:
— the node's `stateless` is false
— the node sits inside exactly 1 availability-zone group
— this does not hold:
— the node sits inside at least one cell group

Message

Stateful node '{{node.id}}' lives in exactly one availability zone. A zone outage takes its state with it.

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

Applies to · 648 components

Categories: compute

AI service ai-service Application server app-server Big data cluster big-data-cluster Container orchestrator container-orchestrator Edge appliance edge-appliance Matching engine matching-engine Media transcoder media-transcoder ML inference ml-inference ML platform ml-platform Virtual desktop pool virtual-desktop Virtual machine virtual-machine Worker worker Workflow engine workflow-engine

Tripped by · 4

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.

digital-walletreference doordash-deliveryreference figma-multiplayerreference pinterest-feedreference

Source

1# yaml-language-server: $schema=../schema/rule.schema.json
2# A stateful compute node pinned to exactly one availability zone disappears with that
3# zone, and its state with it. Nodes inside a cell group are exempt: in a cell
4# architecture the cell is deliberately single-zone and redundancy comes from the other
5# cells.
6# Tripped by: designs/doordash-delivery.broken.yaml
7schemaVersion: "1"
8type: "rule"
9id: "stateful-node-without-zone-redundancy"
10severity: "error"
11select:
12  node:
13    category: "compute"
14when:
15  all:
16    - prop: "stateless"
17      equals: false
18    - inGroup:
19        kind: "availability-zone"
20        count:
21          eq: 1
22    - not:
23        inGroup:
24          kind: "cell"
25message: "Stateful node '{{node.id}}' lives in exactly one availability zone. A zone outage takes its state with it."

The same page as markdown, for an agent: /catalogue/rules/stateful-node-without-zone-redundancy.md