Running VerneMQ using Docker

As well as being available as packages that can be installed directly into the operating systems, VerneMQ is also available as a Docker image. Below is an example of how to set up a couple of VerneMQ

Start a VerneMQ cluster node

To use the provided docker images the VerneMQ EULA must be accepted. See Accepting the VerneMQ EULA for more information.

docker run --name vernemq1 -d gojektech/vernemq

Sometimes you need to configure a forwarding for ports (on a Mac for example):

docker run -p 1883:1883 --name vernemq1 -d gojektech/vernemq

This starts a new node that listens on 1883 for MQTT connections and on 8080 for MQTT over websocket connections. However, at this moment the broker won't be able to authenticate the connecting clients. To allow anonymous clients use the DOCKER_VERNEMQ_ALLOW_ANONYMOUS=on environment variable.

docker run -e "DOCKER_VERNEMQ_ALLOW_ANONYMOUS=on" --name vernemq1 -d gojektech/vernemq

Warning: Setting allow_anonymous=on completely disables authentication in the broker and plugin authentication hooks are never called! See more information about the authentication hooks here.

VerneMQ Configuration

All configuration parameters that are available in vernemq.conf can be defined using the DOCKER_VERNEMQ prefix followed by the confguration parameter name. E.g: allow_anonymous=on is -e "DOCKER_VERNEMQ_ALLOW_ANONYMOUS=on" or allow_register_during_netsplit=on is -e "DOCKER_VERNEMQ_ALLOW_REGISTER_DURING_NETSPLIT=on". All available configuration parameters can be found on https://vernemq.com/docs/configuration/.

Logging

VerneMQ store crash and error log files in /var/log/vernemq/, and, by default, doesn't write console log to the disk to avoid filling the container disk space. However this behaviour can be changed by setting the environment variable DOCKER_VERNEMQ_LOG__CONSOLE to both which tells VerneMQ to send logs to stdout and /var/log/vernemq/console.log. For more information please see VerneMQ logging documentation: https://docs.vernemq.com/configuring-vernemq/logging

Remarks

Some of our configuration variables contain dots .. For example if you want to adjust the log level of VerneMQ you'd use -e "DOCKER_VERNEMQ_LOG.CONSOLE.LEVEL=debug". However, some container platforms such as Kubernetes don't support dots and other special characters in environment variables. If you are on such a platform you could substitute the dots with two underscores __. The example above would look like -e "DOCKER_VERNEMQ_LOG__CONSOLE__LEVEL=debug".

There some exceptions on configuration names contains dots. You can see follow examples:

format in vernemq.conf	format in environment variable name
vmq_webhooks.pool_timeout = 60000	DOCKER_VERNEMQ_VMQ_WEBHOOKS__POOL_timeout=6000
vmq_webhooks.pool_timeout = 60000	DOCKER_VERNEMQ_VMQ_WEBHOOKS.pool_timeout=60000

Autojoining a VerneMQ cluster

This allows a newly started container to automatically join a VerneMQ cluster. Assuming you started your first node like the example above you could autojoin the cluster (which currently consists of a single container 'vernemq1') like the following:

docker run -e "DOCKER_VERNEMQ_DISCOVERY_NODE=<IP-OF-VERNEMQ1>" --name vernemq2 -d gojektech/vernemq

(Note, you can find the IP of a docker container using docker inspect <CONTAINER_NAME> | grep \"IPAddress\").

Checking cluster status

To check if the above containers have successfully clustered you can issue the vmq-admin command:

docker exec vernemq1 vmq-admin cluster show
+--------------------+-------+
|        Node        |Running|
+--------------------+-------+
|VerneMQ@172.17.0.151| true  |
|VerneMQ@172.17.0.152| true  |
+--------------------+-------+