emqx/deploy/docker

EMQX

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

• Supported Docker versions:

  the latest release

What is EMQX

EMQX is the world's most scalable open-source MQTT broker with a high performance that connects 100M+ IoT devices in 1 cluster, while maintaining 1M message per second throughput and sub-millisecond latency.

EMQX supports multiple open standard protocols like MQTT, HTTP, QUIC, and WebSocket. It's 100% compliant with MQTT 5.0 and 3.x standard, and secures bi-directional communication with MQTT over TLS/SSL and various authentication mechanisms.

With the built-in powerful SQL-based rules engine, EMQX can extract, filter, enrich and transform IoT data in real-time. In addition, it ensures high availability and horizontal scalability with a masterless distributed architecture, and provides ops-friendly user experience and great observability.

EMQX boasts more than 20K+ enterprise users across 50+ countries and regions, connecting 100M+ IoT devices worldwide, and is trusted by over 400 customers in mission-critical scenarios of IoT, IIoT, connected vehicles, and more, including over 70 Fortune 500 companies like HPE, VMware, Verifone, SAIC Volkswagen, and Ericsson.

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 EMQX 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.

EMQX Configuration

NOTE: All EMQX Configuration in etc/emqx.conf can be configured via environment variables. 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 be 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

EMQX Loaded Modules Configuration

Options	Default	Description
EMQX_LOADED_MODULES	see content below	default EMQX loaded modules

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"

EMQX Loaded Plugins Configuration

Options	Default	Description
EMQX_LOADED_PLUGINS	see content below	default EMQX loaded plugins

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"

EMQX 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 configure them automatically using some magic.

All EMQX plugins can be configured 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 \
    -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 unique number for its own configuration option:

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

Cluster

EMQX 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=[emqx@node1.emqx.io, emqx@node2.emqx.io]"
      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=[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 EMQX 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:latest
    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 \
    --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 EMQX DOCKER PRIVILEGED OR MOUNT SYSTEM PROC IN CONTAINER TO TUNE LINUX KERNEL, IT IS UNSAFE.

Thanks

• @je-al
• @RaymondMouthaan
• @zhongjiewu