What does the DOCKER_HOST variable do?

Question

I\'m new to Docker, using Boot2Docker on OSX. After booting it, this message is given:

To connect the Docker client to the Docker daemon, please set
export DOCKE         


        

Answer 1

It points to the docker host! I followed these steps:

$ boot2docker start

Waiting for VM and Docker daemon to start...
..............................
Started.

To connect the Docker client to the Docker daemon, please set:
    export DOCKER_HOST=tcp://192.168.59.103:2375

$ export DOCKER_HOST=tcp://192.168.59.103:2375

$ docker run ubuntu:14.04 /bin/echo 'Hello world'
Unable to find image 'ubuntu:14.04' locally
Pulling repository ubuntu
9cbaf023786c: Download complete 
511136ea3c5a: Download complete 
97fd97495e49: Download complete 
2dcbbf65536c: Download complete 
6a459d727ebb: Download complete 
8f321fc43180: Download complete 
03db2b23cf03: Download complete 
Hello world

See:
http://docs.docker.com/userguide/dockerizing/