Reference documentation

What is the Sensu Transport?

Sensu services use a message bus (e.g. RabbitMQ) for communication. This message bus communication is provided by the Sensu Transport, which is a library that makes it possible to leverage alternate transport solutions in place of RabbitMQ (the default transport). Sensu services requires access to the same instance of the defined transport (e.g. a RabbitMQ server or cluster) to function. Sensu check requests and check results are published as “messages” to the Sensu Transport, and the corresponding Sensu services receive these messages by subscribing to the appropriate subscriptions.

Selecting a Transport

The Sensu Transport library makes it possible to replace Sensu’s recommended and default transport (RabbitMQ) with alternative solutions. There are currently two (2) transports provided with the sensu-transport library: RabbitMQ and Redis — each presenting unique performance and functional characteristics.

The RabbitMQ Transport is the original Sensu transport, and continues to be the recommended solution for running Sensu in production environments.


  • Native SSL support
  • Pluggable authentication framework
  • Support for ACLs


  • Adds Erlang as a runtime dependency to the Sensu architecture (only on systems where RabbitMQ is running)

The Redis Transport

Because Sensu already depends on Redis as a data store, using Redis as a transport greatly simplifies Sensu’s architecture by removing the need to install/configure RabbitMQ and its dependencies. That said, Redis transport is only considered suitable for simple development environments. Redis transport is NOT recommended for production environments!


  • Simplifies Sensu architecture by removing need for dedicated transport (by using Redis as the data store and transport)
  • Comparable or better throughput/performance than RabbitMQ


  • No native support for SSL
  • No support for transport “consumers” metrics (see Health & Info API)
  • Not Battle tested: known bugs in this transport may cause unexpected behavior
  • Best-effort support only

Transport configuration

Example transport definition

The following is an example transport definition, a JSON configuration file located at /etc/sensu/conf.d/transport.json. This example transport configuration indicates that Redis should be used as the Sensu transport.

  "transport": {
    "name": "redis",
    "reconnect_on_error": true

Maximum transport message size

Use max_message_size to specify the maximum transport message size (in bytes). Specifying a maximum transport message size helps prevent oversized messages from consuming memory and being persisted to the datastore

The following is an example maximum transport message size definition:

  "sensu": {
    "server": {
      "max_message_size": 2097152

Transport DNS resolution

The Sensu Transport will resolve provided hostnames before making connection attempts to the RabbitMQ & Redis transports. Resolving DNS hostnames prior to connecting allows Sensu to properly handle resolution failures, log them, and make further attempts to connect to the selected transport. This also allows Sensu to use DNS as a transport failover mechanism.

Transport definition specification

The Sensu Transport uses the "transport": {} definition scope.

Transport attributes

The following attributes are defined within the "transport": {} definition scope.

description The Transport driver to use.
required false
type String
allowed values rabbitmq, redis
default rabbitmq
"name": "redis"
description Attempt to reconnect after a connection error.
required false
type String
default true
"reconnect_on_error": "false"