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 vernemq/vernemq
Sometimes you need to configure a forwarding for ports (on a Mac for example):
docker run -p 1883:1883 --name vernemq1 -d vernemq/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 vernemq/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.

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 vernemq/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|