ubuntu14 docker無法啟動並出現 Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

偶然一次輸入docker ps的時候，出現 “Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?”錯誤，試過執行

 service docker start 命令，啟動docker服務，

返回  docker start/running, process 2662，

但問題還是不能解決。

 

解決方法：查看docker日記

tail -5f /var/log/upstart/docker.log

output

time="2020-05-18T09:42:35.148670130+08:00" level=info msg="ClientConn switching  balancer to \"pick_first\"" module=grpc
time="2020-05-18T09:42:35.148707378+08:00" level=info msg="pickfirstBalancer: Ha ndleSubConnStateChange: 0xc420372530, CONNECTING" module=grpc
time="2020-05-18T09:42:35.148827393+08:00" level=info msg="pickfirstBalancer: Ha ndleSubConnStateChange: 0xc420372530, READY" module=grpc
time="2020-05-18T09:42:35.148849129+08:00" level=info msg="Loading containers: s tart." Error starting daemon: Error initializing network controller: error obtaining co ntroller instance: failed to get bridge network configurations from store: error while populating kmap: invalid database

出現上述黃色標注的錯誤，執行

rm -rf /var/lib/docker/network/files/*
service docker start
docker ps

不在出現“Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?”問題解決