Skip to main content
Version: Next

Configuration

Overview

RabbitMQ comes with default built-in settings. Those can be entirely sufficient in some environment (e.g. development and QA). For all other cases, as well as production deployment tuning, there is a way to configure many things in the broker as well as plugins.

This guide covers a number of topics related to configuration:

and more.

Since configuration affects many areas of the system, including plugins, individual documentation guides dive deeper into what can be configured. Runtime Tuning is a companion to this guide that focuses on the configurable parameters in the runtime. Production Checklist is a related guide that outlines what settings will likely need tuning in most production environments.

Means of Configuration

A RabbitMQ node can be configured using a number of mechanisms responsible for different areas:

Ways of configuring RabbitMQ
MechanismDescription

Configuration File(s)

Contains server and plugin settings for TCP listeners and other networking-related settings, TLS, resource constraints (alarms), authentication and authorisation backends, message store settings, and more.

Environment Variables

Used to define node name, file and directory locations, runtime flags taken from the shell, or set in the environment configuration file, rabbitmq-env.conf (Linux, MacOS, BSD) and rabbitmq-env-conf.bat (Windows)

rabbitmqctl

When internal authentication/authorisation backend is used, rabbitmqctl is the tool that manages virtual hosts, users and permissions. It is also used to manage runtime parameters and policies.

rabbitmq-queues

rabbitmq-queues is the tool that manages settings specific to quorum queues.

rabbitmq-plugins

rabbitmq-plugins is the tool that manages plugins.

rabbitmq-diagnostics

rabbitmq-diagnostics allows for inspection of node state, including effective configuration, as well as many other metrics and health checks.

Parameters and Policies

defines cluster-wide settings which can change at run time as well as settings that are convenient to configure for groups of queues (exchanges, etc) such as including optional queue arguments.

Runtime (Erlang VM) Flags

Control lower-level aspects of the system: memory allocation settings, inter-node communication buffer size, runtime scheduler settings and more.

Operating System Kernel Limits

Control process limits enforced by the kernel: max open file handle limit, max number of processes and kernel threads, max resident set size and so on.

Most settings are configured using the first two methods. This guide, therefore, focuses on them.

Configuration File(s)

Introduction

While some settings in RabbitMQ can be tuned using environment variables, most are configured using a main configuration file named rabbitmq.conf.

This includes configuration for the core server as well as plugins. An additional configuration file can be used to configure settings that cannot be expressed in the main file's configuration format. This is covered in more details below.

The sections below cover the syntax and location of both files, where to find examples, and more.

Config File Locations

Default config file locations vary between operating systems and package types.

This topic is covered in more detail in the rest of this guide.

When in doubt about RabbitMQ config file location, consult the log file and/or management UI as explained in the following section.

How to Find Config File Location

The active configuration file can be verified by inspecting the RabbitMQ log file. It will show up in the log file at the top, along with the other broker boot log entries. For example:

node           : rabbit@example
home dir : /var/lib/rabbitmq
config file(s) : /etc/rabbitmq/advanced.config
: /etc/rabbitmq/rabbitmq.conf

If the configuration file cannot be found or read by RabbitMQ, the log entry will say so:

node           : rabbit@example
home dir : /var/lib/rabbitmq
config file(s) : /var/lib/rabbitmq/hare.conf (not found)

Alternatively, the location of configuration files used by a local node, use the rabbitmq-diagnostics status command:

# displays key
rabbitmq-diagnostics status

and look for the Config files section that would look like this:

Config files

* /etc/rabbitmq/advanced.config
* /etc/rabbitmq/rabbitmq.conf

To inspect the locations of a specific node, including nodes running remotely, use the -n (short for --node) switch:

rabbitmq-diagnostics status -n [node name]

Finally, config file location can be found in the management UI, together with other details about nodes.

When troubleshooting configuration settings, it is very useful to verify that the config file path is correct, exists and can be loaded (e.g. the file is readable) before verifying effective node configuration. Together, these steps help quickly narrow down most common misconfiguration problems.

The Modern and Old Config File Formats

All supported RabbitMQ versions use an ini-like, sysctl configuration file format for the main configuration file. The file is typically named rabbitmq.conf.

The new config format is much simpler, easier for humans to read and machines to generate. It is also relatively limited compared to the classic config format used prior to RabbitMQ 3.7.0. For example, when configuring LDAP support, it may be necessary to use deeply nested data structures to express desired configuration.

To accommodate this need, modern RabbitMQ versions allow for both formats to be used at the same time in separate files: rabbitmq.conf uses the new style format and is recommended for most settings, and advanced.config covers more advanced settings that the ini-style configuration cannot express. This is covered in more detail in the following sections.

Configuration FileFormat UsedPurpose
rabbitmq.confNew style format (sysctl or ini-like)

Primary configuration file with a .conf extension. Should be used for most settings. It is easier for humans to read and machines (deployment tools) to generate. Not every setting can be expressed in this format.

advanced.configClassic (Erlang terms)

A limited number of settings that cannot be expressed in the new style configuration format, such as LDAP queries. Only should be used when necessary.

rabbitmq-env.conf (rabbitmq-env.conf.bat on Windows)Environment variable pairs

Used to set environment variables relevant to RabbitMQ in one place.

Compare this examplary rabbitmq.conf file

# A new style format snippet. This format is used by rabbitmq.conf files.
ssl_options.cacertfile = /path/to/ca_certificate.pem
ssl_options.certfile = /path/to/server_certificate.pem
ssl_options.keyfile = /path/to/server_key.pem
ssl_options.verify = verify_peer
ssl_options.fail_if_no_peer_cert = true

to

%% A classic format snippet, now used by advanced.config files.
[
{rabbit, [{ssl_options, [{cacertfile, "/path/to/ca_certificate.pem"},
{certfile, "/path/to/server_certificate.pem"},
{keyfile, "/path/to/server_key.pem"},
{verify, verify_peer},
{fail_if_no_peer_cert, true}]}]}
].

The Main Configuration File, rabbitmq.conf

The configuration file rabbitmq.conf allows the RabbitMQ server and plugins to be configured. The file uses the sysctl format, unlike advanced.config and the original rabbitmq.config (both use the Erlang terms format).

The syntax can be briefly explained in 3 lines:

  • One setting uses one line
  • Lines are structured Key = Value
  • Any line starting with a # character is a comment

A minimalistic example configuration file follows:

# this is a comment
listeners.tcp.default = 5673

The same example in the classic config format:

%% this is a comment
[
{rabbit, [
{tcp_listeners, [5673]}
]
}
].

This example will alter the port RabbitMQ listens on for AMQP 0-9-1 and AMQP 1.0 client connections from 5672 to 5673.

The RabbitMQ server source repository contains an example rabbitmq.conf file named rabbitmq.conf.example. It contains examples of most of the configuration items you might want to set (with some very obscure ones omitted), along with documentation for those settings.

Documentation guides such as Networking, TLS, or Access Control contain many examples in relevant formats.

Note that this configuration file is not to be confused with the environment variable configuration files, rabbitmq-env.conf and rabbitmq-env-conf.bat.

To override the main RabbitMQ config file location, use the RABBITMQ_CONFIG_FILE (or RABBITMQ_CONFIG_FILES to use a conf.d-style directory of sorted files) environment variables. Use .conf as file extension for the new style config format, e.g. /etc/rabbitmq/rabbitmq.conf or /data/configuration/rabbitmq/rabbitmq.conf

Using a Directory of .conf Files

A conf.d-style directory of files can also be used. Use RABBITMQ_CONFIG_FILES (note the plural "_FILES") to point the node at a directory of such files:

# uses a directory of .conf files loaded in alphabetical order
RABBITMQ_CONFIG_FILES=/path/to/a/custom/location/rabbitmq/conf.d

Target directory must contain a number of .conf files with the same syntax as rabbitmq.conf.

They will be loaded in alphabetical order. A common naming practice uses numerical prefixes in filenames to make it easier to reason about the order, or make sure a "defaults file" is always loaded first, regardless of how many extra files are generated at deployment time:

ls -lh /path/to/a/custom/location/rabbitmq/conf.d
# => -r--r--r-- 1 rabbitmq rabbitmq 87B Mar 21 19:50 00-defaults.conf
# => -r--r--r-- 1 rabbitmq rabbitmq 4.6K Mar 21 19:52 10-main.conf
# => -r--r--r-- 1 rabbitmq rabbitmq 1.6K Mar 21 19:52 20-tls.conf
# => -r--r--r-- 1 rabbitmq rabbitmq 1.6K Mar 21 19:52 30-federation.conf

Environment Variable Interpolation in rabbitmq.conf

Modern RabbitMQ versions support environment variable interpolation in rabbitmq.conf. For example, to override default user credentials, one can use import a definition file or the following config file in combination with two environment variables:

# environment variable interpolation
default_user = $(SEED_USERNAME)
default_pass = $(SEED_USER_PASSWORD)

Environment variables can be used to configure a portion of a value, for example, cluster name:

cluster_name = deployment-$(DEPLOYMENT_ID)

Environment variable values are interpolated as strings before the config file is parsed and validated. This means that they can be used to override numerical settings (such as ports) or paths (such as TLS certificate and private key paths).

In addition, RabbitMQ respects a number of environment variables for when a value must be known before the configuration file is loaded.

The advanced.config File

warning

This section describes the original configuration format that has been superseded by a modern alternative. A very limited number of features requires the use of this format. When in doubt, use rabbitmq.conf.

Some configuration settings are not possible or are difficult to configure using the sysctl format. As such, it is possible to use an additional config file in the Erlang term format (same as rabbitmq.config). That file is commonly named advanced.config. It will be merged with the configuration provided in rabbitmq.conf.

The RabbitMQ server source repository contains an example advanced.config file named advanced.config.example. It focuses on the options that are typically set using the advanced config.

To override the advanced config file location, use the RABBITMQ_ADVANCED_CONFIG_FILE environment variable.

Location of rabbitmq.conf, advanced.config and rabbitmq-env.conf

Default configuration file location is distribution-specific. RabbitMQ packages or nodes will not create any configuration files. Users and deployment tool should use the following locations when creating the files:

PlatformDefault Configuration File DirectoryExample Configuration File Paths

Generic binary package

$RABBITMQ_HOME/etc/rabbitmq/

$RABBITMQ_HOME/etc/rabbitmq/rabbitmq.conf, $RABBITMQ_HOME/etc/rabbitmq/advanced.config

Debian and Ubuntu

/etc/rabbitmq/

/etc/rabbitmq/rabbitmq.conf, /etc/rabbitmq/advanced.config

RPM-based Linux

/etc/rabbitmq/

/etc/rabbitmq/rabbitmq.conf, /etc/rabbitmq/advanced.config

Windows

%APPDATA%\RabbitMQ\

%APPDATA%\RabbitMQ\rabbitmq.conf, %APPDATA%\RabbitMQ\advanced.config

MacOS Homebrew Formula

${install_prefix}/etc/rabbitmq/, and the Homebrew cellar prefix is usually /usr/local

${install_prefix}/etc/rabbitmq/rabbitmq.conf, ${install_prefix}/etc/rabbitmq/advanced.config

Environment variables can be used to override the location of the configuration file:

# overrides primary config file location
RABBITMQ_CONFIG_FILE=/path/to/a/custom/location/rabbitmq.conf

# overrides advanced config file location
RABBITMQ_ADVANCED_CONFIG_FILE=/path/to/a/custom/location/advanced.config

# overrides environment variable file location
RABBITMQ_CONF_ENV_FILE=/path/to/a/custom/location/rabbitmq-env.conf

When Will Configuration File Changes Be Applied

rabbitmq.conf and advanced.config changes take effect after a node restart.

If rabbitmq-env.conf doesn't exist, it can be created manually in the location specified by the RABBITMQ_CONF_ENV_FILE variable. On Windows systems, it is named rabbitmq-env-conf.bat.

Windows service users will need to re-install the service if configuration file location or any values in ``rabbitmq-env-conf.bat` have changed. Environment variables used by the service would not be updated otherwise.

In the context of deployment automation this means that environment variables such as RABBITMQ_BASE and RABBITMQ_CONFIG_FILE should ideally be set before RabbitMQ is installed. This would help avoid unnecessary confusion and Windows service re-installations.

How to Inspect and Verify Effective Configuration of a Running Node

It is possible to print effective configuration (user provided values from all configuration files merged into defaults) using the rabbitmq-diagnostics environment command:

# inspect effective configuration on a node
rabbitmq-diagnostics environment

to check effective configuration of a specific node, including nodes running remotely, use the -n (short for --node) switch:

rabbitmq-diagnostics environment -n [node name]

The command above will print applied configuration for every application (RabbitMQ, plugins, libraries) running on the node. Effective configuration is computed using the following steps:

  • rabbitmq.conf is translated into the internally used (advanced) config format. These configuration is merged into the defaults
  • advanced.config is loaded if present, and merged into the result of the step above

Effective configuration should be verified together with config file location. Together, these steps help quickly narrow down most common misconfiguration problems.

The rabbitmq.config (Classic Format) File

Prior to RabbitMQ 3.7.0, RabbitMQ config file was named rabbitmq.config and used the same Erlang term format used by advanced.config today. That format is still supported for backwards compatibility.

The classic format is deprecated. Please prefer the new style config format in rabbitmq.conf accompanied by an advanced.config file as needed.

To use a config file in the classic format, export RABBITMQ_CONFIG_FILE to point to the file with a .config extension. The extension will indicate to RabbitMQ that it should treat the file as one in the classic config format.

An example configuration file named rabbitmq.config.example. It contains an example of most of the configuration items in the classic config format.

To override the main RabbitMQ config file location, use the RABBITMQ_CONFIG_FILE environment variable. Use .config as file extension for the classic config format.

The use of classic config format should only be limited to the advanced.config file and settings that cannot be configured using the ini-style config file.

Example Configuration Files

The RabbitMQ server source repository contains examples for the configuration files:

These files contain examples of most of the configuration keys along with a brief explanation for those settings. All configuration items are commented out in the example, so you can uncomment what you need. Note that the example files are meant to be used as, well, examples, and should not be treated as a general recommendation.

In most distributions the example file is placed into the same location as the real file should be placed (see above). On Debian and RPM distributions policy forbids doing so; instead find the file under /usr/share/doc/rabbitmq-server/ or /usr/share/doc/rabbitmq-server-<unreleased>/, respectively.

Core Server Variables Configurable in rabbitmq.conf

These variables are the most common. The list is not complete, as some settings are quite obscure.

KeyDocumentation
listeners.tcp

Ports or hostname/pair on which to listen for "plain" AMQP 0-9-1 and AMQP 1.0 connections (without TLS). See the Networking guide for more details and examples.

Default:

listeners.tcp.default = 5672

listeners.ssl

Ports or hostname/pair on which to listen for TLS-enabled AMQP 0-9-1 and AMQP 1.0 connections. See the TLS guide for more details and examples.

Default: none (not set)

ssl_options

TLS configuration. See the TLS guide.

Default:

ssl_options = none

num_acceptors.tcp

Number of Erlang processes that will accept connections for the TCP listeners.

Default:

num_acceptors.tcp = 10

num_acceptors.ssl

Number of Erlang processes that will accept TLS connections from clients.

Default:

num_acceptors.ssl = 10

distribution.listener.interface

Controls what network interface will be used for communication with other cluster members and CLI tools.

Default:

distribution.listener.interface = 0.0.0.0

distribution.listener.port_range.min

Controls the lower bound of a server port range that will be used for communication with other cluster members and CLI tools.

Default:

distribution.listener.port_range.min = 25672

distribution.listener.port_range.max

Controls the upper bound of a server port range that will be used for communication with other cluster members and CLI tools.

Default:

distribution.listener.port_range.max = 25672

handshake_timeout

Maximum time for AMQP 0-9-1 handshake (after socket connection and TLS handshake), in milliseconds.

Default:

handshake_timeout = 10000

ssl_handshake_timeout

TLS handshake timeout, in milliseconds.

Default:

ssl_handshake_timeout = 5000

vm_memory_high_watermark

Memory threshold at which the flow control is triggered. Can be absolute or relative to the amount of RAM available to the OS:

vm_memory_high_watermark.relative = 0.6
vm_memory_high_watermark.absolute = 2GB

See the memory-based flow control and alarms documentation.

Default:

vm_memory_high_watermark.relative = 0.4

vm_memory_calculation_strategy

Strategy for memory usage reporting. Can be one of the following:

  • allocated: uses Erlang memory allocator statistics
  • rss: uses operating system RSS memory reporting. This uses OS-specific means and may start short lived child processes.
  • legacy: uses legacy memory reporting (how much memory is considered to be used by the runtime). This strategy is fairly inaccurate.
  • erlang: same as legacy, preserved for backwards compatibility

Default:

vm_memory_calculation_strategy = allocated

vm_memory_high_watermark_paging_ratio

Fraction of the high watermark limit at which queues start to page messages out to disc to free up memory. See the memory-based flow control documentation.

Default:

vm_memory_high_watermark_paging_ratio = 0.5

total_memory_available_override_value

Makes it possible to override the total amount of memory available, as opposed to inferring it from the environment using OS-specific means. This should only be used when actual maximum amount of RAM available to the node doesn't match the value that will be inferred by the node, e.g. due to containerization or similar constraints the node cannot be aware of. The value may be set to an integer number of bytes or, alternatively, in information units (e.g 8GB). For example, when the value is set to 4 GB, the node will believe it is running on a machine with 4 GB of RAM.

Default: undefined (not set or used).

disk_free_limit

Disk free space limit of the partition on which RabbitMQ is storing data. When available disk space falls below this limit, flow control is triggered. The value can be set relative to the total amount of RAM or as an absolute value in bytes or, alternatively, in information units (e.g 50MB or 5GB):

disk_free_limit.absolute = 2GB

By default free disk space must exceed 50MB. This must be revisited for production environments. See the Disk Alarms documentation.

Default:

disk_free_limit.absolute = 50MB

queue_leader_locator

Controls the strategy used when selecting a node to host the leader replica of a newly declared queue or stream.

log.file.level

Controls the granularity of logging. The value is a list of log event category and log level pairs.

The level can be one of error (only errors are logged), warning (only errors and warning are logged), info (errors, warnings and informational messages are logged), or debug (errors, warnings, informational messages and debugging messages are logged).

Default:

log.file.level = info

channel_max

Maximum permissible number of channels to negotiate with clients, not including a special channel number 0 used in the protocol. Setting to 0 means "unlimited", a dangerous value since applications sometimes have channel leaks. Using more channels increases memory footprint of the broker.

Default:

channel_max = 2047

channel_operation_timeout

Channel operation timeout in milliseconds (used internally, not directly exposed to clients due to messaging protocol differences and limitations).

Default:

channel_operation_timeout = 15000

max_message_size

The largest allowed message payload size in bytes. Messages of larger size will be rejected with a suitable channel exception.

Default: 134217728

Max value: 536870912

heartbeat

Value representing the heartbeat timeout suggested by the server during connection parameter negotiation. If set to 0 on both ends, heartbeats are deactivated (this is not recommended). See the Heartbeats guide for details.

Default:

heartbeat = 60

default_vhost

Virtual host to create when RabbitMQ creates a new database from scratch. The exchange amq.rabbitmq.log will exist in this virtual host.

Default:

default_vhost = /

default_user

User name to create when RabbitMQ creates a new database from scratch.

Default:

default_user = guest

default_pass

Password for the default user.

Default:

default_pass = guest

default_user_tags

Tags for the default user.

Default:

default_user_tags.administrator = true

default_permissions

Permissions to assign to the default user when creating it.

Default:

default_permissions.configure = .*
default_permissions.read = .*
default_permissions.write = .*

loopback_users

List of users which are only permitted to connect to the broker via a loopback interface (i.e. localhost).

To allow the default guest user to connect remotely (a security practice unsuitable for production use), set this to none:

# awful security practice,
# consider creating a new
# user with secure generated credentials!
loopback_users = none

To restrict another user to localhost-only connections, do it like so (monitoring is the name of the user):

loopback_users.monitoring = true

Default:

# guest uses well known
# credentials and can only
# log in from localhost
# by default
loopback_users.guest = true

cluster_formation.classic_config.nodes

Classic peer discovery backend's list of nodes to contact.

For example, to cluster with nodes rabbit@hostname1 and rabbit@hostname2 on first boot:

cluster_formation.classic_config.nodes.1 = rabbit@hostname1
cluster_formation.classic_config.nodes.2 = rabbit@hostname2

Default: none (not set)

collect_statistics

Statistics collection mode. Primarily relevant for the management plugin. Options are:

  • none (do not emit statistics events)
  • coarse (emit per-queue / per-channel / per-connection statistics)
  • fine (also emit per-message statistics)

Default:

collect_statistics = none

collect_statistics_interval

Statistics collection interval in milliseconds. Primarily relevant for the management plugin.

Default:

collect_statistics_interval = 5000

management_db_cache_multiplier

Affects the amount of time the management plugin will cache expensive management queries such as queue listings. The cache will multiply the elapsed time of the last query by this value and cache the result for this amount of time.

Default:

management_db_cache_multiplier = 5

auth_mechanisms

SASL authentication mechanisms to offer to clients.

Default:

auth_mechanisms.1 = PLAIN
auth_mechanisms.2 = AMQPLAIN

auth_backends

List of authentication and authorisation backends to use. See the access control guide for details and examples.

Other databases than rabbit_auth_backend_internal are available through plugins.

Default:

auth_backends.1 = internal

reverse_dns_lookups

Set to true to have RabbitMQ perform a reverse DNS lookup on client connections, and present that information through rabbitmqctl and the management plugin.

Default:

reverse_dns_lookups = false

delegate_count

Number of delegate processes to use for intra-cluster communication. On a machine which has a very large number of cores and is also part of a cluster, you may wish to increase this value.

Default:

delegate_count = 16

tcp_listen_options

Default socket options. You may want to change these when you troubleshoot network issues.

Default:

tcp_listen_options.backlog = 128
tcp_listen_options.nodelay = true
tcp_listen_options.linger.on = true
tcp_listen_options.linger.timeout = 0


tcp_listen_options.exit_on_close = false

Set tcp_listen_options.exit_on_close to true to have RabbitMQ try to immediately close TCP socket when client disconnects. Note that this cannot guarantee immediate TCP socket resource release by the kernel.


tcp_listen_options.keepalive = false

Set tcp_listen_options.keepalive to true to enable TCP keepalives.


cluster_partition_handling

How to handle network partitions. Available modes are:

  • ignore
  • autoheal
  • pause_minority
  • pause_if_all_down

pause_if_all_down mode requires additional parameters:

  • nodes
  • recover

See the documentation on partitions for more information.

Default:

cluster_partition_handling = ignore

cluster_keepalive_interval

How frequently nodes should send keepalive messages to other nodes (in milliseconds). Note that this is not the same thing as net_ticktime; missed keepalive messages will not cause nodes to be considered down.

Default:

cluster_keepalive_interval = 10000

queue_index_embed_msgs_below

Size in bytes of message below which messages will be embedded directly in the queue index. You are advised to read the persister tuning documentation before changing this.

Default:

queue_index_embed_msgs_below = 4096

mnesia_table_loading_retry_timeout

Timeout used when waiting for Mnesia tables in a cluster to become available.

Default:

mnesia_table_loading_retry_timeout = 30000

mnesia_table_loading_retry_limit

Retries when waiting for Mnesia tables in the cluster startup. Note that this setting is not applied to Mnesia upgrades or node deletions.

Default:

mnesia_table_loading_retry_limit = 10

queue_leader_locator

queue leader location strategy. Available strategies are:

  • balanced
  • client-local

Default:

queue_leader_locator = client-local

proxy_protocol

If set to true, RabbitMQ will expect a proxy protocol header to be sent first when an AMQP connection is opened. This implies to set up a proxy protocol-compliant reverse proxy (e.g. HAproxy or AWS ELB) in front of RabbitMQ. Clients can't directly connect to RabbitMQ when proxy protocol is enabled, so all connections must go through the reverse proxy.

See the networking guide for more information.

Default:

proxy_protocol = false

cluster_name

Operator-controlled cluster name. This name is used to identify a cluster, and by the federation and Shovel plugins to record the origin or path of transferred messages. Can be set to any arbitrary string to help identify the cluster (eg. london). This name can be inspected by AMQP 0-9-1 clients in the server properties map.

Default: by default the name is derived from the first (seed) node in the cluster.

The following configuration settings can be set in the advanced config file only, under the rabbit section.

KeyDocumentation
msg_store_index_module

Implementation module for queue indexing. You are advised to read the message store tuning documentation before changing this.

Default: rabbit_msg_store_ets_index

{rabbit, [
{msg_store_index_module, rabbit_msg_store_ets_index}
]}

backing_queue_module

Implementation module for queue contents.

Default:

{rabbit, [
{backing_queue_module, rabbit_variable_queue}
]}

msg_store_file_size_limit

Message store segment file size. Changing this for a node with an existing (initialised) database is dangerous and can lead to data loss!

Default: 16777216

{rabbit, [
%% Changing this for a node
%% with an existing (initialised) database is dangerous and can
%% lead to data loss!
{msg_store_file_size_limit, 16777216}
]}

trace_vhosts

Used internally by the tracer. You shouldn't change this.

Default:

{rabbit, [
{trace_vhosts, []}
]}

msg_store_credit_disc_bound

The credits that a queue process is given by the message store.

By default, a queue process is given 4000 message store credits, and then 800 for every 800 messages that it processes.

Messages which need to be paged out due to memory pressure will also use this credit.

The Message Store is the last component in the credit flow chain. Learn about credit flow.

This value only takes effect when messages are persisted to the message store. If messages are embedded on the queue index, then modifying this setting has no effect because credit_flow is NOT used when writing to the queue index.

Default:

{rabbit, [
{msg_store_credit_disc_bound, {4000, 800}}
]}

queue_index_max_journal_entries

After how many queue index journal entries it will be flushed to disk.

Default:

{rabbit, [
{queue_index_max_journal_entries, 32768}
]}

Several plugins that ship with RabbitMQ have dedicated documentation guides that cover plugin configuration:

Configuration Value Encryption

Sensitive advanced.config entries (e.g. password, URL containing credentials) can be encrypted. RabbitMQ nodes then decrypt encrypted entries on boot.

Note that encrypted configuration entries don't make the system meaningfully more secure. Nevertheless, they allow deployments of RabbitMQ to conform to regulations in various countries requiring that no sensitive data should appear in plain text in configuration files.

Encrypted values must be inside an Erlang encrypted tuple: {encrypted, ...}. Here is an example of a configuration file with an encrypted password for the default user:

[
{rabbit, [
{default_user, <<"guest">>},
{default_pass,
{encrypted,
<<"cPAymwqmMnbPXXRVqVzpxJdrS8mHEKuo2V+3vt1u/fymexD9oztQ2G/oJ4PAaSb2c5N/hRJ2aqP/X0VAfx8xOQ==">>
}
},
{config_entry_decoder, [
{passphrase, <<"mypassphrase">>}
]}
]}
].

Note the config_entry_decoder key with the passphrase that RabbitMQ will use to decrypt encrypted values.

The passphrase doesn't have to be hardcoded in the configuration file, it can be in a separate file:

[
{rabbit, [
%% ...
{config_entry_decoder, [
{passphrase, {file, "/path/to/passphrase/file"}}
]}
]}
].

RabbitMQ can also request an operator to enter the passphrase when it starts by using {passphrase, prompt}.

Encrypting advanced.config Values Using CLI Tools

Use rabbitmqctl and the encode command to encrypt values:

# <<"guest">> here is a value to encode, as an Erlang binary,
# as it would have appeared in advanced.config
rabbitmqctl encode '<<"guest">>' mypassphrase
{encrypted,<<"... long encrypted value...">>}
# "amqp://fred:secret@host1.domain/my_vhost" here is a value to encode, provided as an Erlang string,
# as it would have appeared in advanced.config
rabbitmqctl encode '"amqp://fred:secret@host1.domain/my_vhost"' mypassphrase
{encrypted,<<"... long encrypted value...">>}

Or, on Windows:

# <<"guest">> here is a value to encode, as an Erlang binary,
# as it would have appeared in advanced.config
rabbitmqctl encode "<<""guest"">>" mypassphrase
{encrypted,<<"... long encrypted value...">>}
# "amqp://fred:secret@host1.domain/my_vhost" here is a value to encode, provided as an Erlang string,
# as it would have appeared in advanced.config
rabbitmqctl encode '"amqp://fred:secret@host1.domain/my_vhost"' mypassphrase
{encrypted,<<"... long encrypted value...">>}

Decrypting advanced.config Values Using CLI Tools

Use the decode command to decrypt values:

rabbitmqctl decode '{encrypted, <<"...">>}' mypassphrase
# => <<"guest">>
rabbitmqctl decode '{encrypted, <<"...">>}' mypassphrase
# => "amqp://fred:secret@host1.domain/my_vhost"

Or, on Windows:

rabbitmqctl decode "{encrypted, <<""..."">>}" mypassphrase
# => <<"guest">>
rabbitmqctl decode "{encrypted, <<""..."">>}" mypassphrase
# => "amqp://fred:secret@host1.domain/my_vhost"

Values of different types can be encoded. The example above encodes both binaries (<<"guest">>) and strings ("amqp://fred:secret@host1.domain/my_vhost").

Encryption Settings: Cipher, Hashing Function, Number of Iterations

The encryption mechanism uses PBKDF2 to produce a derived key from the passphrase. The default hash function is SHA512 and the default number of iterations is 1000. The default cipher is AES 256 CBC.

These defaults can be changed in the configuration file:

[
{rabbit, [
...
{config_entry_decoder, [
{passphrase, "mypassphrase"},
{cipher, blowfish_cfb64},
{hash, sha256},
{iterations, 10000}
]}
]}
].

Or, using CLI tools:

rabbitmqctl encode --cipher blowfish_cfb64 --hash sha256 --iterations 10000 \
'<<"guest">>' mypassphrase

Or, on Windows:

rabbitmqctl encode --cipher blowfish_cfb64 --hash sha256 --iterations 10000 \
"<<""guest"">>" mypassphrase

Configuration Using Environment Variables

Certain server parameters can be configured using environment variables: node name, RabbitMQ configuration file location, inter-node communication ports, Erlang VM flags, and so on.

Path and Directory Name Restrictions

Some of the environment variable configure paths and locations (node's base or data directory, plugin source and expansion directories, and so on). Those paths have must exclude a number of characters:

  • * and ? (on Linux, macOS, BSD and other UNIX-like systems)
  • ^ and ! (on Windows)
  • [ and ]
  • { and }

The above characters will render the node unable to start or function as expected (e.g. expand plugins and load their metadata).

Linux, MacOS, BSD

On UNIX-based systems (Linux, MacOS and flavours of BSD) it is possible to use a file named rabbitmq-env.conf to define environment variables that will be used by the broker. Its location is configurable using the RABBITMQ_CONF_ENV_FILE environment variable.

rabbitmq-env.conf uses the standard environment variable names but without the RABBITMQ_ prefix. For example, the RABBITMQ_CONFIG_FILE variable appears below as CONFIG_FILE and RABBITMQ_NODENAME becomes NODENAME:

# Example rabbitmq-env.conf file entries. Note that the variables
# do not have the RABBITMQ_ prefix.
#
# Overrides node name
NODENAME=bunny@myhost

# Specifies new style config file location
CONFIG_FILE=/etc/rabbitmq/rabbitmq.conf

# Specifies advanced config file location
ADVANCED_CONFIG_FILE=/etc/rabbitmq/advanced.config

See the rabbitmq-env.conf man page for details.

Windows

The easiest option to customise names, ports or locations is to configure environment variables in the Windows dialogue: Start > Settings > Control Panel > System > Advanced > Environment Variables. Then create or edit the system variable name and value.

Alternatively it is possible to use a file named rabbitmq-env-conf.bat to define environment variables that will be used by the broker. Its location is configurable using the RABBITMQ_CONF_ENV_FILE environment variable.

Windows service users will need to re-install the service if configuration file location or any values in ``rabbitmq-env-conf.bat` changed. Environment variables used by the service would not be updated otherwise.

This can be done using the installer or on the command line with administrator permissions:

  • Start an administrative command prompt
  • cd into the sbin folder under the RabbitMQ server installation directory (such as C:\Program Files (x86)\RabbitMQ Server\rabbitmq_server-{version}\sbin)
  • Run rabbitmq-service.bat stop to stop the service
  • Run rabbitmq-service.bat remove to remove the Windows service (this will not remove RabbitMQ or its data directory)
  • Set environment variables via command line, i.e. run commands like the following:
    set RABBITMQ_BASE=C:\Data\RabbitMQ
  • Run rabbitmq-service.bat install
  • Run rabbitmq-service.bat start

This will restart the node in a way that makes the environment variable and rabbitmq-env-conf.bat changes to be observable to it.

Environment Variables Used by RabbitMQ

All environment variables used by RabbitMQ use the prefix RABBITMQ_ (except when defined in rabbitmq-env.conf or rabbitmq-env-conf.bat).

Environment variables set in the shell environment take priority over those set in rabbitmq-env.conf or rabbitmq-env-conf.bat, which in turn override RabbitMQ built-in defaults.

The table below describes key environment variables that can be used to configure RabbitMQ. More variables are covered in the File and Directory Locations guide.

  • NameDescription
    RABBITMQ_NODE_IP_ADDRESS

    Change this if you only want to bind to one network interface. Binding to two or more interfaces can be set up in the configuration file.

    Default: an empty string, meaning "bind to all network interfaces".

    RABBITMQ_NODE_PORT

    See Networking guide for more information on ports used by various parts of RabbitMQ.

    Default: 5672.

    RABBITMQ_DIST_PORT

    Port used for inter-node and CLI tool communication. Ignored if node config file sets kernel.inet_dist_listen_min or kernel.inet_dist_listen_max keys. See Networking for details, and Windows Configuration for Windows-specific details.

    Default: RABBITMQ_NODE_PORT + 20000

    ERL_EPMD_ADDRESS

    Interface(s) used by epmd, a component in inter-node and CLI tool communication.

    Default: all available interfaces, both IPv6 and IPv4.

    ERL_EPMD_PORT

    Port used by epmd, a component in inter-node and CLI tool communication.

    Default: 4369

    RABBITMQ_DISTRIBUTION_BUFFER_SIZE

    Outgoing data buffer size limit to use for inter-node communication connections, in kilobytes. Values lower than 64 MB are not recommended.

    Default: 128000

    RABBITMQ_NODENAME

    The node name should be unique per Erlang-node-and-machine combination. To run multiple nodes, see the clustering guide.

    Default:

    • Unix:* rabbit@$HOSTNAME

    • Windows: rabbit@%COMPUTERNAME%

    RABBITMQ_CONFIG_FILE

    Main RabbitMQ config file path, for example, /etc/rabbitmq/rabbitmq.conf or /data/configuration/rabbitmq.conf for new style configuration format files. If classic config format it used, the extension must be .config

    Default:

    • Generic UNIX: $RABBITMQ_HOME/etc/rabbitmq/rabbitmq.conf

    • Debian: /etc/rabbitmq/rabbitmq.conf
    • RPM: /etc/rabbitmq/rabbitmq.conf
    • MacOS(Homebrew): ${install_prefix}/etc/rabbitmq/rabbitmq.conf, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ\rabbitmq.conf

    RABBITMQ_CONFIG_FILES

    Path to a directory of RabbitMQ configuration files in the new-style (.conf) format. The files will be loaded in alphabetical order. Prefixing each files with a number is a common practice.

    Default:

    • Generic UNIX: $RABBITMQ_HOME/etc/rabbitmq/conf.d

    • Debian: /etc/rabbitmq/conf.d
    • RPM: /etc/rabbitmq/conf.d
    • MacOS(Homebrew): ${install_prefix}/etc/rabbitmq/conf.d, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ\conf.d

    RABBITMQ_ADVANCED_CONFIG_FILE

    "Advanced" (Erlang term-based) RabbitMQ config file path with a .config file extension. For example, /data/rabbitmq/advanced.config.

    Default:

    • Generic UNIX: $RABBITMQ_HOME/etc/rabbitmq/advanced.config

    • Debian: /etc/rabbitmq/advanced.config
    • RPM: /etc/rabbitmq/advanced.config
    • MacOS (Homebrew): ${install_prefix}/etc/rabbitmq/advanced.config, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ\advanced.config

    RABBITMQ_CONF_ENV_FILE

    Location of the file that contains environment variable definitions (without the RABBITMQ_ prefix). Note that the file name on Windows is different from other operating systems.

    Default:

    • Generic UNIX package: $RABBITMQ_HOME/etc/rabbitmq/rabbitmq-env.conf
    • Ubuntu and Debian: /etc/rabbitmq/rabbitmq-env.conf
    • RPM: /etc/rabbitmq/rabbitmq-env.conf
    • MacOS (Homebrew): ${install_prefix}/etc/rabbitmq/rabbitmq-env.conf, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ\rabbitmq-env-conf.bat

    RABBITMQ_LOG_BASE

    Can be used to override log files directory location.

    Default:

    • Generic UNIX package: $RABBITMQ_HOME/var/log/rabbitmq
    • Ubuntu and Debian packages: /var/log/rabbitmq
    • RPM: /var/log/rabbitmq
    • MacOS (Homebrew): ${install_prefix}/var/log/rabbitmq, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ\log

    RABBITMQ_MNESIA_BASE

    This base directory contains sub-directories for the RabbitMQ server's node database, message store and cluster state files, one for each node, unless RABBITMQ_MNESIA_DIR is set explicitly. It is important that effective RabbitMQ user has sufficient permissions to read, write and create files and subdirectories in this directory at any time. This variable is typically not overridden. Usually RABBITMQ_MNESIA_DIR is overridden instead.

    Default:

    • Generic UNIX package: $RABBITMQ_HOME/var/lib/rabbitmq/mnesia
    • Ubuntu and Debian packages: /var/lib/rabbitmq/mnesia/
    • RPM: /var/lib/rabbitmq/plugins
    • MacOS (Homebrew): ${install_prefix}/var/lib/rabbitmq/mnesia, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ

    RABBITMQ_MNESIA_DIR

    The directory where this RabbitMQ node's data is stored. This includes a schema database, message stores, cluster member information and other persistent node state.

    Default:

    • Generic UNIX package: $RABBITMQ_MNESIA_BASE/$RABBITMQ_NODENAME
    • Ubuntu and Debian packages: $RABBITMQ_MNESIA_BASE/$RABBITMQ_NODENAME
    • RPM: $RABBITMQ_MNESIA_BASE/$RABBITMQ_NODENAME
    • MacOS (Homebrew): ${install_prefix}/var/lib/rabbitmq/mnesia/$RABBITMQ_NODENAME, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %APPDATA%\RabbitMQ\$RABBITMQ_NODENAME

    RABBITMQ_PLUGINS_DIR

    The list of directories where plugin archive files are located and extracted from. This is PATH-like variable, where different paths are separated by an OS-specific separator (: for Unix, ; for Windows). Plugins can be installed to any of the directories listed here. Must not contain any characters mentioned in the path restriction section. See CLI tools guide to learn about the effects of changing this variable on rabbitmq-plugins.

    Default:

    • Generic UNIX package: $RABBITMQ_HOME/plugins
    • Ubuntu and Debian packages: /var/lib/rabbitmq/plugins
    • RPM: /var/lib/rabbitmq/plugins
    • MacOS (Homebrew): ${install_prefix}/Cellar/rabbitmq/${version}/plugins, the Homebrew prefix is usually /usr/local or /opt/homebrew

    • Windows: %RABBITMQ_HOME%\plugins

    RABBITMQ_PLUGINS_EXPAND_DIR

    The directory the node expand (unpack) plugins to and use it as a code path location. Must not contain any characters mentioned in the path restriction section.

    Default:

    • Generic UNIX package: $RABBITMQ_MNESIA_BASE/$RABBITMQ_NODENAME-plugins-expand
    • Ubuntu and Debian packages: $RABBITMQ_MNESIA_BASE/$RABBITMQ_NODENAME-plugins-expand
    • RPM: $RABBITMQ_MNESIA_BASE/$RABBITMQ_NODENAME-plugins-expand
    • MacOS (Homebrew): ${install_prefix}/var/lib/rabbitmq/mnesia/$RABBITMQ_NODENAME-plugins-expand

    • Windows: %APPDATA%\RabbitMQ\$RABBITMQ_NODENAME-plugins-expand

    RABBITMQ_USE_LONGNAME

    When set to true this will cause RabbitMQ to use fully qualified names to identify nodes. This may prove useful in environments that use fully-qualified domain names or use IP addresses as hostnames or part of node names. Note that it is not possible to switch a node from short name to long name without resetting it.

    Default: false

    RABBITMQ_SERVICENAME

    The name of the installed Windows service. This will appear in services.msc.

    Default: RabbitMQ.

    RABBITMQ_CONSOLE_LOG

    Set this variable to new or reuse to redirect console output from the server to a file named %RABBITMQ_SERVICENAME% in the default RABBITMQ_BASE directory.

    • If not set, console output from the server will be discarded (default).
    • new: a new file will be created each time the service starts.
    • reuse: the file will be overwritten each time the service starts.

    Default: (none)

    RABBITMQ_SERVER_CODE_PATH

    Extra code path (a directory) to be specified when starting the runtime. Will be passed to the erl command when a node is started.

    Default: (none)

    RABBITMQ_CTL_ERL_ARGS

    Parameters for the erl command used when invoking rabbitmqctl. This could be set to specify a range of ports to use for Erlang distribution:
    -kernel inet_dist_listen_min 35672
    -kernel inet_dist_listen_max 35680

    Default: (none)

    RABBITMQ_SERVER_ERL_ARGS

    Standard parameters for the erl command used when invoking the RabbitMQ Server. This should be overridden for debugging purposes only. Overriding this variable replaces the default value.

    Default:

    • Unix:* +P 1048576 +t 5000000 +stbt db +zdbbl 128000

    • Windows: None

    RABBITMQ_SERVER_ADDITIONAL_ERL_ARGS

    Additional parameters for the erl command used when invoking the RabbitMQ Server. The value of this variable is appended to the default list of arguments (RABBITMQ_SERVER_ERL_ARGS).

    Default:

    • Unix:* None
    • Windows: None

    RABBITMQ_SERVER_START_ARGS

    Extra parameters for the erl command used when invoking the RabbitMQ Server. This will not override RABBITMQ_SERVER_ERL_ARGS.

    Default: (none)

    RABBITMQ_DEFAULT_USER

    This environment variable is only meant to be used in development and CI environments. This has the same meaning as default_user in rabbitmq.conf but higher priority. This option may be more convenient in cases where providing a config file is impossible, and environment variables is the only way to seed a user.

    Default: (none)

    RABBITMQ_DEFAULT_PASS

    This environment variable is only meant to be used in development and CI environments. This has the same meaning as default_pass in rabbitmq.conf but higher priority. This option may be more convenient in cases where providing a config file is impossible, and environment variables is the only way to seed a user.

    Default: (none)

    RABBITMQ_DEFAULT_VHOST

    This environment variable is only meant to be used in development and CI environments. This has the same meaning as default_vhost in rabbitmq.conf but higher priority. This option may be more convenient in cases where providing a config file is impossible, and environment variables is the only way to seed users and virtual hosts.

    Default: (none)

    Besides the variables listed above, there are several environment variables which tell RabbitMQ where to locate its database, log files, plugins, configuration and so on.

    Finally, some environment variables are operating system-specific.

    NameDescription
    HOSTNAME

    The name of the current machine.

    Default:

    • Unix, Linux: env hostname
    • MacOS: env hostname -s

    COMPUTERNAME

    The name of the current machine.

    Default:

    • Windows: localhost

    ERLANG_SERVICE_MANAGER_PATH

    This path is the location of erlsrv.exe, the Erlang service wrapper script.

    Default:

    • Windows Service: %ERLANG_HOME%\erts-<var>x.x.x</var>\bin

    Operating System Kernel Limits

    Most operating systems enforce limits on kernel resources: virtual memory, stack size, open file handles and more. To Linux users these limits can be known as "ulimit limits".

    RabbitMQ nodes are most commonly affected by the maximum open file handle limit. Default limit value on most Linux distributions is usually 1024, which is very low for a messaging broker (or generally, any data service). See Production Checklist for recommended values.

    Modifying Limits

    With systemd (Modern Linux Distributions)

    On distributions that use systemd, the OS limits are controlled via a configuration file at /etc/systemd/system/rabbitmq-server.service.d/limits.conf. For example, to set the max open file handle limit (nofile) to 64000:

    [Service]
    LimitNOFILE=64000

    See systemd documentation to learn about the supported limits and other directives.

    With Docker

    To configure kernel limits for Docker containers, use the "default-ulimits" key in Docker daemon configuration file. The file has to be installed on Docker hosts at /etc/docker/daemon.json:

    {
    "default-ulimits": {
    "nofile": {
    "Name": "nofile",
    "Hard": 64000,
    "Soft": 64000
    }
    }
    }

    Without systemd (Older Linux Distributions)

    The most straightforward way to adjust the per-user limit for RabbitMQ on distributions that do not use systemd is to edit the /etc/default/rabbitmq-server (provided by the RabbitMQ Debian package) or rabbitmq-env.conf to invoke ulimit before the service is started.

    ulimit -S -n 4096

    This soft limit cannot go higher than the hard limit (which defaults to 4096 in many distributions). The hard limit can be increased via /etc/security/limits.conf. This also requires enabling the pam_limits.so module and re-login or reboot.

    Note that limits cannot be changed for running OS processes.