Random channel placement under heavy-tail traffic

errorshared-host-per-channel-without-isolation

With heavy-tail traffic a few channels carry most of the load. Assigning channels at random lands those hot channels on arbitrary hosts, and every tenant sharing a host suffers for it.

Severity: error
Selects: every node of kind realtime-gateway
Components in scope: 20

What it checks

It looks at every node of kind realtime-gateway, and fires when:

— all of these hold:
— the node's `channelAssignment` is "random"
— the design requirement `traffic.skew` is "heavy-tail"

Message

Realtime gateway '{{node.id}}' assigns channels randomly while the design declares heavy-tail traffic. Hot channels will degrade unrelated tenants on the same host.

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

Applies to · 20 components

Real-time gateway realtime-gateway

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.

discord-messagesreference facebook-messengerreference slack-messagingreference twitch-livereference

Source

1# yaml-language-server: $schema=../schema/rule.schema.json
2# With heavy-tail traffic a few channels carry most of the load. Random channel
3# assignment lands those hot channels on arbitrary hosts and every tenant sharing that
4# host suffers. Assign channels by hash or sticky placement so hot spots are predictable
5# and movable.
6# Tripped by: designs/slack-messaging.broken.yaml
7schemaVersion: "1"
8type: "rule"
9id: "shared-host-per-channel-without-isolation"
10severity: "error"
11select:
12  node:
13    kind: "realtime-gateway"
14when:
15  all:
16    - prop: "channelAssignment"
17      equals: "random"
18    - requirement: "traffic.skew"
19      equals: "heavy-tail"
20message: "Realtime gateway '{{node.id}}' assigns channels randomly while the design declares heavy-tail traffic. Hot channels will degrade unrelated tenants on the same host."

The same page as markdown, for an agent: /catalogue/rules/shared-host-per-channel-without-isolation.md