Quick reference

Where to get help:

https://emqx.io, https://github.com/emqx/emqx-rel, or https://github.com/emqx/emqx
Where to file issues:

https://github.com/emqx/emqx-rel/issues
Supported architectures

amd64, arm64v8, arm32v7, i386, s390x
Supported Docker versions:

the latest release

What is EMQ X

EMQ X MQTT broker is a fully open source, highly scalable, highly available distributed MQTT messaging broker for IoT, M2M and Mobile applications that can handle tens of millions of concurrent clients.

Starting from 3.0 release, EMQ X broker fully supports MQTT V5.0 protocol specifications and backward compatible with MQTT V3.1 and V3.1.1, as well as other communication protocols such as MQTT-SN, CoAP, LwM2M, WebSocket and STOMP. The 3.0 release of the EMQ X broker can scaled to 10+ million concurrent MQTT connections on one cluster.

How to use this image

Run emqx

Execute some command under this docker image

docker run -d --name emqx emqx/emqx:$(tag)

For example

docker run -d --name emqx -p 18083:18083 -p 1883:1883 emqx/emqx:latest

The emqx broker runs as linux user emqx in the docker container.

Configuration

Use the environment variable to configure the EMQ X docker container.

The environment variables which with EMQX_ prefix are mapped to configuration file, . get replaced by __.

Example:

EMQX_LISTENER__SSL__EXTERNAL__ACCEPTORS <--> listener.ssl.external.acceptors
EMQX_MQTT__MAX_PACKET_SIZE              <--> mqtt.max_packet_size

Also the environment variables which with PLATFORM_ prefix are mapped to template string in configuration file.

PLATFORM_ETC_DIR                   <--> {{ platform_etc_dir }}

Non mapped environment variables:

EMQX_NAME
EMQX_HOST

These environment variables will ignore for configuration file.

EMQ X Configuration

NOTE: All EMQ X Configuration in etc/emqx.conf could config by environment. The following list is just an example, not a complete configuration.

Options	Default	Mapped	Description
EMQX_NAME	container name	none	emqx node short name
EMQX_HOST	container IP	none	emqx node host, IP or FQDN
EMQX_WAIT_TIME	5	none	wait time in sec before timeout
PLATFORM_ETC_DIR	/opt/emqx/etc	{{ platform_etc_dir }}	The etc directory
PLATFORM_LOG_DIR	/opt/emqx/log	{{ platform_log_dir }}	The log directory
EMQX_NODE__NAME	EMQX_NAME@EMQX_HOST	node.name	Erlang node name, name@ipaddress/host
EMQX_NODE__COOKIE	emqx_dist_cookie	node.cookie	cookie for cluster
EMQX_LOG__CONSOLE	console	log.console	log console output method
EMQX_ALLOW_ANONYMOUS	true	allow_anonymous	allow mqtt anonymous login
EMQX_LISTENER__TCP__EXTERNAL	1883	listener.tcp.external	MQTT TCP port
EMQX_LISTENER__SSL__EXTERNAL	8883	listener.ssl.external	MQTT TCP TLS/SSL port
EMQX_LISTENER__WS__EXTERNAL	8083	listener.ws.external	HTTP and WebSocket port
EMQX_LISTENER__WSS__EXTERNAL	8084	listener.wss.external	HTTPS and WSS port
EMQX_LISTENER__API__MGMT	8080	listener.api.mgmt	MGMT API port
EMQX_MQTT__MAX_PACKET_SIZE	64KB	mqtt.max_packet_size	Max Packet Size Allowed

The list is incomplete and may changed with etc/emqx.conf and plugin configuration files. But the mapping rule is similar.

If set EMQX_NAME and EMQX_HOST, and unset EMQX_NODE__NAME, EMQX_NODE__NAME=$EMQX_NAME@$EMQX_HOST.

For example, set mqtt tcp port to 1883

docker run -d --name emqx -e EMQX_LISTENER__TCP__EXTERNAL=1883 -p 18083:18083 -p 1883:1883 emqx/emqx:latest

EMQ Loaded Modules Configuration

Oprtions	Default	Description
EMQX_LOADED_MODULES	see content below	default modules emqx loaded

Default environment variable EMQX_LOADED_MODULES, including

emqx_mod_acl_internal
emqx_mod_presence

# The default EMQX_LOADED_MODULES env
EMQX_LOADED_MODULES="emqx_mod_acl_internal,emqx_mod_acl_internal"

For example, set EMQX_LOADED_MODULES=emqx_mod_delayed,emqx_mod_rewrite to load these two modules.

You can use comma, space or other separator that you want.

All the modules defined in env EMQX_LOADED_MODULES will be loaded.

EMQX_LOADED_MODULES="emqx_mod_delayed,emqx_mod_rewrite"
EMQX_LOADED_MODULES="emqx_mod_delayed emqx_mod_rewrite"
EMQX_LOADED_MODULES="emqx_mod_delayed | emqx_mod_rewrite"

EMQ Loaded Plugins Configuration

Oprtions	Default	Description
EMQX_LOADED_PLUGINS	see content below	default plugins emqx loaded

Default environment variable EMQX_LOADED_PLUGINS, including

emqx_recon
emqx_retainer
emqx_management
emqx_dashboard

# The default EMQX_LOADED_PLUGINS env
EMQX_LOADED_PLUGINS="emqx_recon,emqx_retainer,emqx_management,emqx_dashboard"

For example, set EMQX_LOADED_PLUGINS= emqx_auth_redis,emqx_auth_mysql to load these two plugins.

You can use comma, space or other separator that you want.

All the plugins defined in EMQX_LOADED_PLUGINS will be loaded.

EMQX_LOADED_PLUGINS="emqx_auth_redis,emqx_auth_mysql"
EMQX_LOADED_PLUGINS="emqx_auth_redis emqx_auth_mysql"
EMQX_LOADED_PLUGINS="emqx_auth_redis | emqx_auth_mysql"

EMQ X Plugins Configuration

The environment variables which with EMQX_ prefix are mapped to all emqx plugins' configuration file, . get replaced by __.

Example:

EMQX_AUTH__REDIS__SERVER   <--> auth.redis.server
EMQX_AUTH__REDIS__PASSWORD <--> auth.redis.password

Don't worry about where to find the configuration file of emqx plugins, this docker image will find and config them automatically using some magic.

All plugin of emqx project could config in this way, following the environment variables mapping rule above.

Assume you are using redis auth plugin, for example:

#EMQX_AUTH__REDIS__SERVER="redis.at.yourserver"
#EMQX_AUTH__REDIS__PASSWORD="password_for_redis"

docker run -d --name emqx -p 18083:18083 -p 1883:1883 -p 4369:4369 \
    -e EMQX_LISTENER__TCP__EXTERNAL=1883 \
    -e EMQX_LOADED_PLUGINS="emqx_auth_redis" \
    -e EMQX_AUTH__REDIS__SERVER="your.redis.server:6379" \
    -e EMQX_AUTH__REDIS__PASSWORD="password_for_redis" \
    -e EMQX_AUTH__REDIS__PASSWORD_HASH=plain \
    emqx/emqx:latest

Mask Sensitive Configuration

Use MASK_CONFIG_FILTER to hide senstive configuration values from leaking to logging system.

For example, set MASK_CONFIG_FILTER="password|token" to hide all configuration names containing those keywords.

By default emqx masks the configuration using following filter "password|passwd|key|token|secret". Setting MASK_CONFIG_FILTER will be merged with the default filter.

The configuration should match whole word (after splitting it by '.') with MASK_CONFIG_FILTER. You can use commas, spaces or other required separators to separate different words.

Cluster

EMQ X supports a variety of clustering methods, see our documentation for details.

Let's create a static node list cluster from docker-compose.

Create docker-compose.yaml:

version: '3'

services:
  emqx1:
    image: emqx/emqx:v4.0.0
    environment:
    - "EMQX_NAME=emqx"
    - "EMQX_HOST=node1.emqx.io"
    - "EMQX_CLUSTER__DISCOVERY=static"
    - "EMQX_CLUSTER__STATIC__SEEDS=emqx@node1.emqx.io, emqx@node2.emqx.io"
    networks:
      emqx-bridge:
        aliases:
        - node1.emqx.io
  
  emqx2:
    image: emqx/emqx:v4.0.0
    environment:
    - "EMQX_NAME=emqx"
    - "EMQX_HOST=node2.emqx.io"
    - "EMQX_CLUSTER__DISCOVERY=static"
    - "EMQX_CLUSTER__STATIC__SEEDS=emqx@node1.emqx.io, emqx@node2.emqx.io"
    networks:
      emqx-bridge:
        aliases:
        - node2.emqx.io

networks:
  emqx-bridge:
    driver: bridge

Start the docker-compose cluster
```
$ docker-compose -p my_emqx up -d
```

View cluster

$ docker exec -it my_emqx_emqx1_1 sh -c "emqx_ctl cluster status"
Cluster status: #{running_nodes => ['emqx@node1.emqx.io','emqx@node2.emqx.io'],
                  stopped_nodes => []}

Persistence

If you want to persist the EMQ X docker container, you need to keep the following directories:

/opt/emqx/data
/opt/emqx/etc
/opt/emqx/log

Since data in these folders are partially stored under the /opt/emqx/data/mnesia/${node_name}, the user also needs to reuse the same node name to see the previous state. In detail, one needs to specify the two environment variables: EMQX_NAME and EMQX_HOST, EMQX_HOST set as 127.0.0.1 or network alias would be useful.

In if you use docker-compose, the configuration would look something like this:

volumes:
  vol-emqx-data:
    name: foo-emqx-data
  vol-emqx-etc:
    name: foo-emqx-etc
  vol-emqx-log:
    name: foo-emqx-log

services:
  emqx:
    image: emqx/emqx:v4.0.0
    restart: always
    environment:
      EMQX_NAME: foo_emqx
      EMQX_HOST: 127.0.0.1
    volumes:
      - vol-emqx-data:/opt/emqx/data
      - vol-emqx-etc:/opt/emqx/etc
      - vol-emqx-log:/opt/emqx/log

Kernel Tuning

Under linux host machine, the easiest way is tuning host machine's kernel.

If you want tune linux kernel by docker, you must ensure your docker is latest version (>=1.12).

docker run -d --name emqx -p 18083:18083 -p 1883:1883 -p 4369:4369 \
    --sysctl fs.file-max=2097152 \
    --sysctl fs.nr_open=2097152 \
    --sysctl net.core.somaxconn=32768 \
    --sysctl net.ipv4.tcp_max_syn_backlog=16384 \
    --sysctl net.core.netdev_max_backlog=16384 \
    --sysctl net.ipv4.ip_local_port_range=1000 65535 \
    --sysctl net.core.rmem_default=262144 \
    --sysctl net.core.wmem_default=262144 \
    --sysctl net.core.rmem_max=16777216 \
    --sysctl net.core.wmem_max=16777216 \
    --sysctl net.core.optmem_max=16777216 \
    --sysctl net.ipv4.tcp_rmem=1024 4096 16777216 \
    --sysctl net.ipv4.tcp_wmem=1024 4096 16777216 \
    --sysctl net.ipv4.tcp_max_tw_buckets=1048576 \
    --sysctl net.ipv4.tcp_fin_timeout=15 \
    emqx/emqx:latest

REMEMBER: DO NOT RUN EMQ X DOCKER PRIVILEGED OR MOUNT SYSTEM PROC IN CONTAINER TO TUNE LINUX KERNEL, IT IS UNSAFE.

polymatx/emqx-docker