[SOLVED] second ssh session can not connect to docker host

Issue

I have server with debian operating system. I installed docker on it and it works fine, as you can see as follow:

root@3053b0461a3c:/# which wget
/usr/bin/wget
root@3053b0461a3c:/#

An ubuntu based container is running.
Then I started a second terminal, connect via ssh to server and type in console

docker ps

But as output I've got the message:

Cannot connect to the Docker daemon. Is the docker daemon running on this host?

Why the docker service is not running?

Solution

Unset the environment variable DOCKER_HOST and it should work.

https://github.com/docker/docker/blob/eff810aed688879f67a3730c41d9adce4637470f/docs/installation/ubuntulinux.md

Try unset DOCKER_HOST

In most unix-based (or -like) environments that I've seen there is the concept of environment variables, which can be considered as dynamic configuration. The 2 functions available are:

• set which sets to an environment variable a special value
• unset which removes an environment variable.

On the case of DOCKER_HOST, docker uses this variable to know whether it should attach to a network host, e.g. tcp://192.137.23.11 or to a local Unix socket.

Answered By - ipinak