After updating Ubuntu to 21.04 from 20.10 docker seems to be running in:
/run/docker.sock but the docker client goes to look for it on:
/var/run/docker.sock How can I fix this?
Elaborating a bit, running a docker command I get:
$ docker ps Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? But the docker service seems to be running with the docker socket in another location (out of var):
$ sudo systemctl status docker ● docker.service - Docker Application Container Engine Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled) Active: active (running) since Mon 2021-05-17 10:14:49 CEST; 5s ago TriggeredBy: ● docker.socket Docs: Main PID: 10163 (dockerd) Tasks: 18 Memory: 40.5M CGroup: / └─10163 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.599580310+02:00" level=warning msg="Your kernel does not support CPU realtime scheduler" may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.599624934+02:00" level=warning msg="Your kernel does not support cgroup blkio weight" may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.599642841+02:00" level=warning msg="Your kernel does not support cgroup blkio weight_device" may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.599907138+02:00" level=info msg="Loading containers: start." may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.740160234+02:00" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17.0.0/16. Daemon option --bip can be use> may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.838137738+02:00" level=info msg="Loading containers: done." may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.854381886+02:00" level=info msg="Docker daemon" commit=20.10.2-0ubuntu2 graphdriver(s)=overlay2 version=20.10.2 may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.854462072+02:00" level=info msg="Daemon has completed initialization" may 17 10:14:49 xps-laptop systemd[1]: Started Docker Application Container Engine. may 17 10:14:49 xps-laptop dockerd[10163]: time="2021-05-17T10:14:49.879020578+02:00" level=info msg="API listen on /run/docker.sock" Edit (content of /lib/systemd/system/docker.socket):
$ cat /lib/systemd/system/docker.socket [Unit] Description=Docker Socket for the API [Socket] ListenStream=/var/run/docker.sock SocketMode=0660 SocketUser=root SocketGroup=docker [Install] WantedBy=sockets.target Edit 2 (content of /lib/systemd/system/docker.service):
$ cat /lib/systemd/system/docker.service [Unit] Description=Docker Application Container Engine Documentation= After=network-online.target firewalld.service containerd.service Wants=network-online.target Requires=docker.socket Wants=containerd.service [Service] Type=notify # the default is not to use systemd for cgroups because the delegate issues still # exists and systemd currently does not support the cgroup feature set required # for containers run by docker ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock ExecReload=/bin/kill -s HUP $MAINPID TimeoutSec=0 RestartSec=2 Restart=always # Note that StartLimit* options were moved from "Service" to "Unit" in systemd 229. # Both the old, and new location are accepted by systemd 229 and up, so using the old location # to make them work for either version of systemd. StartLimitBurst=3 # Note that StartLimitInterval was renamed to StartLimitIntervalSec in systemd 230. # Both the old, and new name are accepted by systemd 230 and up, so using the old name to make # this option work for either version of systemd. StartLimitInterval=60s # Having non-zero Limit*s causes performance problems due to accounting overhead # in the kernel. We recommend using cgroups to do container-local accounting. LimitNOFILE=infinity LimitNPROC=infinity LimitCORE=infinity # Comment TasksMax if your systemd version does not support it. # Only systemd 226 and above support this option. TasksMax=infinity # set delegate yes so that systemd does not reset the cgroups of docker containers Delegate=yes # kill only the docker process, not all processes in the cgroup KillMode=process OOMScoreAdjust=-500 [Install] WantedBy=multi-user.target 1 Answer
First, check that the symlink in /var/run is in place and pointing to /run (it appears this was ok in your case).
Next, try changing the "ExecStart" statement by creating a Drop-In config:
sudo mkdir -p /etc/systemd/system/docker.service.d sudo nano /etc/systemd/system/docker.service.d/options.conf Now add the following to the file /etc/systemd/system/docker.service.d/options.conf:
[Service] ExecStart= ExecStart=/usr/bin/dockerd -H unix:// --containerd=/run/containerd/containerd.sock Now reload systemd config and reload docker daemon:
sudo systemctl daemon-reload sudo systemctl restart docker If you also want the daemon to listen on a remote port, add -H tcp://0.0.0.0:2375 to the "ExecStart" entry in /etc/systemd/system/docker.service.d/options.conf:
[Service] ExecStart= ExecStart=/usr/bin/dockerd -H unix:// -H tcp://0.0.0.0:2375 --containerd=/run/containerd/containerd.sock However, it appears in your case that changing to -H unix:// did the trick.
