解決在 Ubuntu 14.04 底下 Docker 服務無法開啟的問題

有時候在 ubuntu 14.04 底下 docker 會因為某些原因無法運作. 例如:

sudo docker images

結果得到下列錯誤:

Get http:///var/run/docker.sock/v1.19/images/json: dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?

執行 docker service 時:

sudo service docker start

會得到下面結果:

Failed to start docker.service: Unit docker.service is masked.

這時候可以執行下列指令:

systemctl unmask docker.service
systemctl unmask docker.socket
systemctl start docker.service

Docker 又可以重新運作了.