EMQ Docker

EMQ (Erlang MQTT Broker) is a distributed, massively scalable, highly extensible MQTT message broker written in Erlang/OTP.

Current docker image size: 37.1 MB

Get emqttd

You can build this docker image by yourself.

git clone -b master https://github.com/emqtt/emq_docker.git
cd emq_docker
docker build -t emq:latest .

Run emqttd

Execute some command under this docker image

docker run --rm -ti -v `pwd`:$(somewhere) emq/$(image) $(somecommand)

For example

docker run --rm -ti --name emq -p 18083:18083 -p 1883:1883 emq:latest

The emqtt erlang broker runs as linux user emqtt in the docker container.

Configuration

Use the environment variable to configure the EMQ docker container

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

Example:

EMQ_LISTENER__SSL__EXTERNAL__ACCEPTORS <--> listener.ssl.external.acceptors
EMQ_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:

EMQ_NAME
EMQ_HOST

These environment variables will ignore for configuration file.

EMQ Configuration

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

Options	Default	Mapped	Description
EMQ_NAME	container name	none	emq node short name
EMQ_HOST	container IP	none	emq node host, IP or FQDN
EMQ_WAIT_TIME	5	none	wait time in sec before timeout
EMQ_JOIN_CLUSTER	none	none	Initial cluster to join
EMQ_ADMIN_PASSWORD	public	none	emq admin password
PLATFORM_ETC_DIR	/opt/emqtt/etc	{{ platform_etc_dir }}	The etc directory
PLATFORM_LOG_DIR	/opt/emqtt/log	{{ platform_log_dir }}	The log directory
EMQ_NODE__NAME	EMQ_NAME@EMQ_HOST	node.name	Erlang node name, name@ipaddress/host
EMQ_NODE__COOKIE	emq_dist_cookie	node.cookie	cookie for cluster
EMQ_LOG__CONSOLE	console	log.console	log console output method
EMQ_MQTT__ALLOW_ANONYMOUS	true	mqtt.allow_anonymous	allow mqtt anonymous login
EMQ_LISTENER__TCP__EXTERNAL	1883	listener.tcp.external	MQTT TCP port
EMQ_LISTENER__SSL__EXTERNAL	8883	listener.ssl.external	MQTT TCP TLS/SSL port
EMQ_LISTENER__WS__EXTERNAL	8083	listener.ws.external	HTTP and WebSocket port
EMQ_LISTENER__WSS__EXTERNAL	8084	listener.wss.external	HTTPS and WSS port
EMQ_LISTENER__API__MGMT	8080	listener.api.mgmt	mgmt API port
EMQ_MQTT__MAX_PACKET_SIZE	64KB	mqtt.max_packet_size	Max Packet Size Allowed

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

If set EMQ_NAME and EMQ_HOST, and unset EMQ_NODE__NAME, EMQ_NODE__NAME=$EMQ_NAME@$EMQ_HOST.

For example, set mqtt tcp port to 1883

docker run --rm -ti --name emq -e EMQ_LISTENER__TCP__EXTERNAL=1883 -p 18083:18083 -p 1883:1883 emq:latest

EMQ Loaded Plugins Configuration

Oprtions	Default	Description
EMQ_LOADED_PLUGINS	see content below	default plugins emq loaded

Default environment variable EMQ_LOADED_PLUGINS, including

• emq_recon
• emq_modules
• emq_retainer
• emq_dashboard

# The default EMQ_LOADED_PLUGINS env
EMQ_LOADED_PLUGINS="emq_recon,emq_modules,emq_retainer,emq_dashboard"

For example, load emq_auth_redis plugin, set it into EMQ_LOADED_PLUGINS and use any separator to separates it.

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

All the plugin you defined in env EMQ_LOADED_PLUGINS will be loaded.

EMQ_LOADED_PLUGINS="emq_auth_redis,emq_recon,emq_modules,emq_retainer,emq_dashboard"
EMQ_LOADED_PLUGINS="emq_auth_redis emq_recon emq_modules emq_retainer emq_dashboard"
EMQ_LOADED_PLUGINS="emq_auth_redis | emq_recon | emq_modules | emq_retainer | emq_dashboard"

EMQ Plugin Configuration

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

Example:

EMQ_AUTH__REDIS__SERVER   <--> auth.redis.server
EMQ_AUTH__REDIS__PASSWORD <--> auth.redis.password

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

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

Assume you are using redis auth plugin, for example:

#EMQ_AUTH__REDIS__SERVER="redis.at.yourserver"
#EMQ_AUTH__REDIS__PASSWORD="password_for_redis"

docker run --rm -ti --name emq -p 18083:18083 -p 1883:1883 -p 4369:4369 \
    -e EMQ_LISTENER__TCP__EXTERNAL=1883 \
    -e EMQ_LOADED_PLUGINS="emq_auth_redis,emq_recon,emq_modules,emq_retainer,emq_dashboard" \
    -e EMQ_AUTH__REDIS__SERVER="your.redis.server:6379" \
    -e EMQ_AUTH__REDIS__PASSWORD="password_for_redis" \
    -e EMQ_AUTH__REDIS__PASSWORD_HASH=plain \
    emq:latest

Cluster

You can specify a initial cluster and join.

Note: You must publsh port 4369 and range of port 6000-6999 for EMQ Clustered.

For example, using 6000-6100 for cluster.

docker run --rm -ti --name emq -p 18083:18083 -p 1883:1883 -p 4369:4369 -p 6000-6100:6000-6100 \
    -e EMQ_NAME="emq" \
    -e EMQ_HOST="s2.emqtt.io" \
    -e EMQ_LISTENER__TCP__EXTERNAL=1883 \
    -e EMQ_JOIN_CLUSTER="emq@s1.emqtt.io" \
    emq:latest

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 --rm -ti --name emq -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 \
    emq:latest

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

Thanks

@je-al emqxarchive#2 The idea of variable names get mapped, dots get replaced by __.