Is the docker daemon running?

原文

剛在新的Centos上安裝Docker-CE,後運行docker run hello-world報錯Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

解決辦法
$ systemctl daemon-reload
$ sudo service docker restart
$ sudo service docker status (should see active (running))
$ sudo docker run hello-world

docker 客戶端經過unix:///var/run/docker.sock與docker daemon通訊，unix:///var/run/docker.sock須要管理員權限才能訪問，因此要麼運行sudo docker run hello-world，要麼將當前用戶添加在docker用戶組中
sudo usermod -aG docker $USER