steelenwang / emqx-docker

An Open-Source, Cloud-Native, Distributed MQTT Message Broker for IoT.

Quick reference

• Where to get help:

  https://emqx.io or https://github.com/emqx/emqx

• Where to file issues:

  https://github.com/emqx/emqx/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.

By default, the environment variables with EMQX_ prefix are mapped to key-value pairs in configuration files.

You can change the prefix by overriding "HOCON_ENV_OVERRIDE_PREFIX".

Example:

EMQX_LISTENERS__SSL__DEFAULT__ACCEPTORS <--> listeners.ssl.default.acceptors
EMQX_ZONES__DEFAULT__MQTT__MAX_PACKET_SIZE <--> zones.default.mqtt.max_packet_size

• Prefix EMQX_ is removed
• All upper case letters is replaced with lower case letters
• __ is replaced with .

If HOCON_ENV_OVERRIDE_PREFIX=DEV_ is set:

DEV_LISTENER__SSL__EXTERNAL__ACCEPTORS <--> listener.ssl.external.acceptors
DEV_MQTT__MAX_PACKET_SIZE              <--> mqtt.max_packet_size

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

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__LISTENERS__TCP__DEFAULT__BIND=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_presence

# The default EMQX_LOADED_MODULES env
EMQX_LOADED_MODULES="emqx_mod_presence"

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_rule_engine
• 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_retainer,emqx_rule_engine 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_retainer,emqx_rule_engine"
EMQX_LOADED_PLUGINS="emqx_retainer emqx_rule_engine"
EMQX_LOADED_PLUGINS="emqx_retainer | emqx_rule_engine"

EMQ X Plugins Configuration

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

Example:

EMQX_RETAINER__STORAGE_TYPE <--> retainer.storage_type
EMQX_RETAINER__MAX_PAYLOAD_SIZE <--> retainer.max_payload_size

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_RETAINER__STORAGE_TYPE = "ram"
#EMQX_RETAINER.MAX_PAYLOAD_SIZE = 1MB

docker run -d --name emqx -p 18083:18083 -p 1883:1883 -p 4369:4369 \
    -e EMQX_LISTENERS__TCP__DEFAULT=1883 \
    -e EMQX_LOADED_PLUGINS="emqx_retainer" \
    -e EMQX_RETAINER__STORAGE_TYPE = "ram" \
    -e EMQX_RETAINER__MAX_PAYLOAD_SIZE = 1MB \
    emqx/emqx:latest

For numbered configuration options where the number is next to a . such as:

• backend.redis.pool1.server
• backend.redis.hook.message.publish.1

You can configure an arbitrary number of them as long as each has a uniq unber for it's own configuration option:

docker run -d --name emqx -p 18083:18083 -p 1883:1883 -p 4369:4369 \
    -e EMQX_BACKEND_REDIS_POOL1__SERVER=127.0.0.1:6379
    [...]
    -e EMQX_BACKEND__REDIS__POOL5__SERVER=127.0.0.5:6379
    -e EMQX_BACKEND__REDIS__HOOK_MESSAGE__PUBLISH__1='{"topic": "persistant/topic1", "action": {"function": "on_message_publish"}, "pool": "pool1"}'
    -e EMQX_BACKEND__REDIS__HOOK_MESSAGE__PUBLISH__2='{"topic": "persistant/topic2", "action": {"function": "on_message_publish"}, "pool": "pool1"}'
    -e EMQX_BACKEND__REDIS__HOOK_MESSAGE__PUBLISH__3='{"topic": "persistant/topic3", "action": {"function": "on_message_publish"}, "pool": "pool1"}'
    [...]
    -e EMQX_BACKEND__REDIS__HOOK_MESSAGE__PUBLISH__13='{"topic": "persistant/topic13", "action": {"function": "on_message_publish"}, "pool": "pool1"}'
    emqx/emqx:latest

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:latest
      environment:
      - "EMQX_NAME=emqx"
      - "EMQX_HOST=node1.emqx.io"
      - "EMQX_CLUSTER__DISCOVERY_STRATEGY=static"
      - "EMQX_CLUSTER__STATIC__SEEDS=[[email protected], [email protected]]"
      networks:
        emqx-bridge:
          aliases:
          - node1.emqx.io
  
    emqx2:
      image: emqx/emqx:latest
      environment:
      - "EMQX_NAME=emqx"
      - "EMQX_HOST=node2.emqx.io"
      - "EMQX_CLUSTER__DISCOVERY_STRATEGY=static"
      - "EMQX_CLUSTER__STATIC__SEEDS=[[email protected], [email protected]]"
      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 => ['[email protected]','[email protected]'],
                    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 guide.

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.

Thanks

• @je-al
• @RaymondMouthaan
• @zhongjiewu