The four RabbitMQ anti-patterns that page you at 3 a.m.

Most RabbitMQ incidents aren't surprises. They're config decisions made months earlier that finally met the right traffic. The four below cause a disproportionate share of after-hours pages, and every one of them is visible in the broker's topology before it fires. A config scan reads that topology and flags them while it's still daylight.

Missing dead-letter exchange

A queue with no dead-letter exchange (DLX) has nowhere to put a message it can't handle. Rejected and expired messages either vanish or, worse, loop — redelivered forever to a consumer that keeps failing them. You discover this when a downstream team asks where their order went and the answer is "nowhere."

Set a DLX so poison messages land somewhere inspectable:

rabbitmqctl set_policy dlx "^orders\." \
  '{"dead-letter-exchange":"orders.dlx"}' \
  --apply-to queues

A scan flags any queue handling real traffic with no DLX configured — the silent-data-loss case you never see coming.

Idle no-consumer queues

A durable queue with zero consumers is a leak with a schedule. Publishers keep writing; nothing reads; depth grows until memory or disk alarms trip and every publisher on the node gets blocked. The queue nobody noticed takes down the queues everybody depends on.

These are trivial to spot in topology — bound, durable, receiving messages, zero consumers — and a scan surfaces them long before the alarm.

Default-exchange overuse

Publishing everything to the default (nameless) exchange by routing key feels convenient. It also hard-codes queue names into producers, kills your ability to fan out or re-route without a code change, and turns a queue rename into a coordinated multi-service deploy. It's not a crash, it's a slow loss of operational flexibility.

Unbounded queue depth

A queue with no max-length and no TTL will, given one bad afternoon, grow without limit. Memory climbs, the node hits its high-watermark, RabbitMQ throttles publishers, and a localized backlog becomes a cluster-wide outage.

Bound it:

rabbitmqctl set_policy maxlen "^events\." \
  '{"max-length":100000,"overflow":"reject-publish"}' \
  --apply-to queues

Catch them before they page you

The thread through all four: they're structural, they're static, and they're readable from the broker's own config. Qarote's config scan walks your topology and flags each one as a finding — so the fix is a calm pull request on Tuesday, not a 3 a.m. page on Saturday.