# Rabbitmq Knowledge Patch > RabbitMQ - Skill: `nevaberry/rabbitmq-knowledge-patch` (Agent Skill, multi-file: 9 files) - Install (CLI): `npx skillmds@latest add nevaberry/rabbitmq-knowledge-patch` - Raw SKILL.md: https://api.skillmd.com/api/skills/nevaberry/rabbitmq-knowledge-patch/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - License: MIT - Author: nevaberry (https://skillmd.com/u/nevaberry) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/nevaberry/rabbitmq-knowledge-patch --- # RabbitMQ Knowledge Patch Use this skill when upgrading or operating RabbitMQ, changing broker or plugin configuration, integrating a protocol client, or updating monitoring and automation. Determine the deployed RabbitMQ and Erlang/OTP versions first, then open the reference that matches the task. ## Reference index | Reference | Topics | | --- | --- | | [migrations-and-deprecations.md](references/migrations-and-deprecations.md) | Upgrade paths, rolling upgrades, Khepri migration, removed settings and deprecated features | | [clustering-configuration-and-operations.md](references/clustering-configuration-and-operations.md) | Cluster formation, feature flags, resource alarms, health checks, limits, diagnostics, Erlang compatibility | | [queues-streams-and-exchanges.md](references/queues-streams-and-exchanges.md) | Queue semantics, quorum queues, streams, exchange limits and routing behavior | | [protocols-and-clients.md](references/protocols-and-clients.md) | AMQP 1.0, AMQP 0-9-1, MQTT, STOMP, WebSocket, Direct Reply-To, client behavior | | [security-and-authentication.md](references/security-and-authentication.md) | OAuth/OIDC, LDAP, TLS, authentication backends, authorization, credential refresh | | [management-api-and-observability.md](references/management-api-and-observability.md) | HTTP API, management UI, Prometheus metrics, logging, definition import/export | | [federation-shovels-and-extensions.md](references/federation-shovels-and-extensions.md) | Federation, Shovels, plugin APIs, peer discovery, Tanzu features | ## Upgrade decision points ### Moving to 4.3 - Upgrade through 4.2.x; 4.3.x accepts upgrades only from 4.2.x. - Enable all stable feature flags before the upgrade. - Khepri is mandatory. Enable `khepri_db` before the first 4.3 node starts, or that node migrates Mnesia metadata during boot. - If the cluster used AMQP 1.0 on 3.13 with `rabbitmq_amqp1_0` enabled, complete a rolling update after enabling `rabbitmq_4.0.0` and before entering 4.3. - Keep a 4.3/4.2 mixed cluster only for the few hours required by a rolling upgrade. - Run 4.3.x on Erlang/OTP 27.0 or later; older runtimes do not start. ### Moving to 4.2 or 4.1 - 4.2 accepts direct upgrades from 4.1.x, 4.0.x, or 3.13.x. Existing Mnesia deployments remain on Mnesia until Khepri is explicitly enabled. - 4.1 accepts 4.0.x or 3.13.x after all stable feature flags are enabled. - A 3.13 cluster already using Khepri cannot upgrade in place to 4.x because the metadata format is incompatible; use a blue-green migration. - Mixed-version clusters exist only for rolling upgrades. Do not enable release-specific features until every node has reached the new series. - Do not use grow-then-shrink as a whole-cluster upgrade strategy; it changes replica identities and can cause large data transfers. ## Breaking removals and defaults ### Metadata and partition handling - 4.3 supports Khepri only. Remove Mnesia-era partition settings: `pause_if_all_down`, `pause_minority`, and `autoheal`. - The accepted keys `cluster_partition_handling`, `cluster_partition_handling.pause_if_all_down.recover`, and `cluster_partition_handling.pause_if_all_down.nodes.$name` are inert. - `rabbitmqctl force_reset` is deprecated because it is incompatible with Khepri. ### Queues and deprecated features - Classic queue v1 storage is gone. Declarations fail if `x-queue-mode` has any value or `x-queue-version` is `1`; convert queues to CQv2 on 4.2 first. - Non-durable, non-exclusive classic queues are rejected by default. Prefer a durable queue, an exclusive transient queue, or a durable queue with TTL. Temporary compatibility requires `deprecated_features.permit.transient_nonexcl_queues = true`. - `amqp_address_v1`, `amqp_filter_set_bug`, `global_qos`, and `queue_master_locator` are denied unless explicitly permitted. `ram_node_type` has been removed. - Administrators can disable individual queue types; clients then cannot declare new queues or streams of those types. ### Removed or ignored settings and tools - The management plugin no longer serves the `rabbitmqadmin` v1 download. Prefer the standalone `rabbitmqadmin` v2. - `rabbitmq-streams set_stream_retention_policy` is a no-op; set retention by policy. - The legacy all-in-one HTTP health check is a no-op; use focused checks. - `tcp_listen_options.buffer` is ignored because AMQP user-space TCP buffers are auto-tuned. Kernel `recbuf` and `sndbuf` still apply. - Remove ineffective `*.cacerts` settings, but retain `cacertfile` where used. - Remove the obsolete etcd TLS keys `fail_if_no_peer_cert`, `dh`, and `dhfile`. ## Queue and stream behavior to re-test ### Quorum queues - Quorum queues use 32 strict priority levels: every higher priority is delivered before a lower one. This replaces the former two-level 2:1 interleaving behavior. - Native delayed retries use `x-delayed-retry-type`, `x-delayed-retry-min`, and `x-delayed-retry-max`, or their policy forms. - Requeue attempts increment `acquired-count`, but only failures increment `delivery-count`; poison-message limits therefore do not necessarily count ordinary returns. - Consumer timeout precedence is consumer argument, queue argument, policy, then global `consumer_timeout`. Timeouts affect quorum and Tanzu JMS queues, not classic queues or streams. - `consumer_disconnected_timeout` defaults to 60 seconds before a partitioned consumer's messages are returned. Policy and per-queue overrides exist. - Delivery limits are policy-mutable. Purging also removes pending at-least-once dead-lettered messages. ### Streams - AMQP 1.0 consumers can combine chunk-level filter values with broker-side SQL expressions over message fields and application properties. - Stream connections allow at most 256 publishers and 256 subscriptions. - Before a successful `open`, Stream frames default to an 8192-byte ceiling, configurable with `stream.initial_frame_max`. - `stream.max_uncompressed_sub_entry_batch_size` defaults to 64 MiB; configure publishers to the same decompression ceiling. - A failed Stream OAuth renewal closes the connection, and the renewed token is reauthorized for the active virtual host. ### Exchanges and routing - A topic binding key may contain at most two `#` wildcards; prefer one final `#` segment. - `x-modulus-hash` is now a core exchange and has restart-stable distribution while bindings remain stable. - `cluster_exchange_limit` caps application declarations cluster-wide and must have the same value on every node. - The local-random exchange type can be disabled with `exchange_types.local_random.enabled = false`. ## Protocol compatibility checks ### AMQP - An AMQP 1.0 message without a header now uses the specification default `durable = false`; send an explicit durable header when required. - AMQP 1.0 supports dynamic nodes, Direct Reply-To, OAuth token renewal, multiple routing keys through string-list annotation `x-cc`, and stream filters. Property filters are limited to 16 properties. - AMQP 0-9-1 clients must offer a pre-authentication `frame_max` of at least 8192. Node.js `amqplib` should be 0.10.7 or newer. - Credential refresh clears AMQP 0-9-1 permission caches, revalidates consumers, and refreshes user tags. Passive declarations require `configure` permission. ### MQTT, STOMP, and WebSocket - MQTT's default maximum packet size is 16 MiB and must not exceed the broker `max_message_size`. - MQTT 5 rejects packet-invalid properties and `Receive Maximum = 0`, and reports `Quota exceeded` when a queue length limit rejects a publish. - Web MQTT enforces pre/post-authentication decompressed-frame ceilings, `login_timeout`, and optional origin allowlists. Web STOMP enforces its frame limit during accumulation. - MQTT, STOMP, and Web MQTT stay blocked until all active resource alarms have cleared. - STOMP destinations affected by the transient non-exclusive queue removal use exclusive queues. ## Security and management checks - Configure OAuth providers explicitly; do not rely on former Azure Entra or Auth0 defaults. Discovery endpoints, scope aliases, selected variables, and forwarded proxy headers are supported. - Plain secrets containing a colon are not encrypted. Prefix supported encrypted values with `encrypted:`. - A configured backend from a known but disabled authentication plugin causes startup to fail. - HTTP API authentication can use a backend chain separate from messaging protocols. Protect the API reference and sensitive users where appropriate. - Management actions that restart federation links or delete Shovels require the `policymaker` tag. - When enabling encrypted management UI credentials, use the same `management.credential_encryption_secret` on every node and wait until the rolling upgrade is complete. ## Operational validation Before stopping a node, run: ```shell rabbitmq-diagnostics check_if_node_is_quorum_critical rabbitmq-upgrade await_online_quorum_plus_one ``` For metadata readiness and quorum leadership, use the focused diagnostics: ```shell rabbitmq-diagnostics check_if_metadata_store_is_initialized rabbitmq-diagnostics check_if_metadata_store_is_initialized_with_data rabbitmq-diagnostics check_for_quorum_queues_without_an_elected_leader \ --vhost "vh-1" "^naming-pattern" ``` Also update 4.2-era Raft metric names and Grafana dashboards, clear stale management UI browser state after an upgrade, and validate the exact deployed configuration against the matching topic reference.