Docker fails to start due to "volume store metadata database: timeout" - docker

I have followed the installation instructions of Docker CE for CentOS. Initially this worked. At some point the system was restarted and now starting Docker fails. Appreciate expert eyes on this matter...
systemctl start docker produces:
Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.
systemctl status docker.service produces:
Apr 21 11:25:23 sec-services-build-1 systemd[1]: Starting Docker Application Container Engine...
Apr 21 11:25:23 sec-services-build-1 dockerd[9693]: time="2017-04-21T11:25:23.370390797+03:00" level=info msg="libcontainerd: previous instance of containerd still alive (8908)"
Apr 21 11:25:23 sec-services-build-1 dockerd[9693]: time="2017-04-21T11:25:23.382492171+03:00" level=warning msg="overlay: the backing xfs filesystem is formatted without d_type support, which leads to incorrect behavior. Reformat the filesystem with ftype=1 to enable d_type support. Running without d_type support will no longer be supported in Docker 17.12."
Apr 21 11:25:23 sec-services-build-1 dockerd[9693]: time="2017-04-21T11:25:23.382547668+03:00" level=info msg="[graphdriver] using prior storage driver: overlay"
Apr 21 11:25:24 sec-services-build-1 dockerd[9693]: Error starting daemon: error while opening volume store metadata database: timeout
Apr 21 11:25:24 sec-services-build-1 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
Apr 21 11:25:24 sec-services-build-1 systemd[1]: Failed to start Docker Application Container Engine.
Apr 21 11:25:24 sec-services-build-1 systemd[1]: Unit docker.service entered failed state.
Apr 21 11:25:24 sec-services-build-1 systemd[1]: docker.service failed.

From here: https://github.com/moby/moby/issues/22507
I ran:
ps axf | grep docker | grep -v grep | awk '{print "kill -9 " $1}' | sudo sh
I was then able to restart docker using:
sudo systemctl start docker

Step 1: systemctl status docker (if docker is running) stop the docker.
step 2: systemctl stop docker.
step 3: dockerd

i got this message when copying volumes from production machine, ended up to overwrite metadata.db inside /var/lib/docker/volumes, then it crashes. A fix is so simple
docker system prune --volumes -f && rm /var/lib/docker/volumes/metadata.db && docker-compose up -d

I encountered the same error.
❶tried
sudo kill -9 1452
multiple times, but it doesn't work. There's still a dockerd process active.
1452 ? Zsl 127:42 [dockerd] <defunct>
❷tried as #Artur Mustafin suggested:
sudo mv /var/lib/docker/volumes/metadata.db /var/lib/docker/volumes/metadata.db.bk
it worked.

so I tried all of these and nothing worked. However what worked was removing all the containers from /var/lib/docker/containers. Then i killed all docker processes (ps -ef | grep docker) then restarted docker and the docker socket. When docker became active I added the containers one at a time and 1 container was what caused the issues

Related

Docker daemon cannot be started for some (hidden) reason

I am trying to push a docker image and noticed that my docker daemon actually is probably not running.
If for example I run:
docker run hello-world
docker: Cannot connect to the Docker daemon at
unix:///var/run/docker.sock. Is the docker daemon running?.
If I try to restart the daemon using:
systemctl start docker
Job for docker.service failed because the control process exited with
error code. See "systemctl status docker.service" and "journalctl -xe"
for details.
Continuing running:
systemctl status docker.service
docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor
preset: enabled)
Active: failed (Result: start-limit-hit) since Wed 2021-05-12 14:45:09
EEST; 43s ago
Docs: https://docs.docker.com
Process: 4810 ExecStart=/usr/bin/dockerd -H fd://
--containerd=/run/containerd/containerd.sock (code=exited, status=1/FAILURE)
Main PID: 4810 (code=exited, status=1/FAILURE)
May 12 14:45:07 iti-554 systemd[1]: docker.service: Unit entered
failed state.
May 12 14:45:07 iti-554 systemd[1]: docker.service: Failed with result
'exit-code'.
May 12 14:45:09 iti-554 systemd[1]: docker.service: Service hold-off
time over, scheduling restart.
May 12 14:45:09 iti-554 systemd[1]: Stopped Docker Application
Container Engine.
May 12 14:45:09 iti-554 systemd[1]: docker.service: Start request
repeated too quickly.
May 12 14:45:09 iti-554 systemd[1]: Failed to start Docker Application
Container Engine.
May 12 14:45:09 iti-554 systemd[1]: docker.service: Unit entered
failed state.
May 12 14:45:09 iti-554 systemd[1]: docker.service: Failed with result
'start-limit-hit'.
which as I understand it it means docker daemon is not loaded (it's in a failed state) and the last reason for this is the start-limit-hit has been reached. This on this side probably means another reason exists for this to happen.
SO, how do I find out which is the actual reason for my docker daemon refusing to start?
If I run to reset the failed attemps counter with:
systemctl reset-failed docker.service
it return without error so I assume it succeeds. And indeed when I check the status it has become:
Active: inactive (dead) since Wed 2021-05-12 14:45:09 EEST; 14min ago
Of course if I run docker daemon again it fails.
Can someone provide any workaround about this issue? I even tried to invoke the commands after restarting (didn't help).
Edit
Well, to my case the problem was a rather stupid one. I had added a daemon.json file with minimal content in it. Just this:
cat /etc/docker/daemon.json
{
"insecure-registries": [
"docker-server.com:10022",
"docker-server.com:10023"
],
}
The problem was that the dangling comma before } made docker search for another parameter. The relevant message shown using journalctl -u docker was:
unable to configure the Docker daemon with file
/etc/docker/daemon.json: invalid character '}' looking for beginning
of object key string
is quite obvious but the previous ones did not help much.
journalctl -u docker gives you docker daemon logs. Maybe u can find something there.
The unix:///var/run/docker.sock requires the correct permission to work. This a security feature for Docker.
Try sudo chmod 755 /var/run/docker.sock and re-run Docker command.
Note the permission number given here may not be suitable for everyone.

docker.socket: Failed with result 'service-start-limit-hit' after protecting docker daemon socket

I followed the steps provided in the documentation here to add tls security for docker api. Certificates are located in ~/.docker/ as well as /etc/docker/ssl/ folders. I added override.conf to /etc/systemd/system/docker.service.d/ with content
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2376 --tlsverify --tlscacert=ca.pem --tlscert=server-cert.pem --tlskey=server-key.pem
Then, I used daemon-reload and docker start
$ systemctl daemon-reload
$ service docker start
The errors in journalctl -xe is:
-- Unit docker.socket has finished starting up.
--
-- The start-up result is RESULT.
Jan 15 21:43:24 cynicalplyaground systemd[1]: docker.service: Start request repeated too quickly.
Jan 15 21:43:24 cynicalplyaground systemd[1]: docker.service: Failed with result 'exit-code'.
Jan 15 21:43:24 cynicalplyaground systemd[1]: Failed to start Docker Application Container Engine.
-- Subject: Unit docker.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- Unit docker.service has failed.
--
-- The result is RESULT.
Jan 15 21:43:24 cynicalplyaground systemd[1]: docker.socket: Failed with result 'service-start-limit-hit'.
Jan 15 21:45:01 cynicalplyaground CRON[12768]: pam_unix(cron:session): session opened for user root by (uid=0)
Jan 15 21:45:01 cynicalplyaground CRON[12769]: (root) CMD (command -v debian-sa1 > /dev/null && debian-sa1 1 1)
Jan 15 21:45:01 cynicalplyaground CRON[12768]: pam_unix(cron:session): session closed for user root
How can I sort this issue?
In the present case the same error occured after the latest manjaro update (2020-01-20).
Tried to change the systemd docker service, as adviced in other cases, but I reverted those changes and finally this was solved with:
a reboot of the system
(like advised here: https://www.reddit.com/r/archlinux/comments/7ya4ug/installing_docker_on_arch_linux/)
Getting to the root of the problem;
systemctl status docker.service
has this:
/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
Trying to run that command, it complains about
unable to configure the Docker daemon with file /etc/docker/daemon.json: EOF
ls -l /etc/docker/daemon.json
-rw-r--r-- 1 root root 0 Jul 30 10:32 /etc/docker/daemon.json
NOTE that the JSON file is empty. Delete it.
For me it was because the docker installer uses iptables for nat. Unfortunately Debian uses nftables. You can convert the entries over to nftables or just setup Debian to use the legacy iptables.
sudo update-alternatives --set iptables /usr/sbin/iptables-legacy
sudo update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
dockerd, should start fine after switching to iptables-legacy.
I have the same issue and just modify the "/usr/bin/dockerd" to "/usr/sbin/dockerd", then it works.
You can check the dockerd path first.
in my case... the host was part of a docker swarm...but the IPv6 was no longer reachable or automatically assigned to the host...
I manually add the old_IPv6
ip -6 address add 28xx:xxxx:x:x:xx:ebff:fe14:xxx dev ens3x
the journalctl -u docker.service mention:
level=fatal msg="Error starting cluster component: could not find local IP address: dial udp [2xxx:xxx:xxxx:xxx]:2377: connect: network is unreachable"
after add manually the IPv6 I was able to start docker so with docker running I leave the "swarm" and reboot
docker swarm leave --force
after reboot the docker services run as usual
For me it was missing disk space. Reboot also helped, but I was stillnot able to build any container.
After pruning some outdated stuff from the docker volumes I was able to continue.
I faced a similar issue on Ubuntu because I added the hosts option to /etc/docker/daemon.json file. That's ok, but for systems that use systemd it may cause conflict with the arguments passed to dockerd on start.
The solution was to delete the /etc/docker/daemon.json's hosts entry and set this config on file /etc/systemd/system/docker.service.d/options.conf.
$ cat /etc/systemd/system/docker.service.d/options.conf
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix://
After that, restart the service.
$ sudo systemctl daemon-reload
$ sudo systemctl restart docker
You may check that your changes has been applied by running docker info. Also, you may note on the docker service status that Drop-In field is using the options.conf created, and dockerd was executed with the specified host list.
$ systemctl status docker
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset>
Drop-In: /etc/systemd/system/docker.service.d
└─options.conf
Active: active (running) since Fri 2022-11-18 01:02:18 EST; 1h 50min ago
TriggeredBy: ● docker.socket
Docs: https://docs.docker.com
Main PID: 1111 (dockerd)
Tasks: 18
Memory: 58.5M
CPU: 1.294s
CGroup: /system.slice/docker.service
└─1111 /usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix://
References:
Daemon configuration file
Control Docker with systemd
I had a similar issue on nixOS installed in a btrfs filesystem.
For me the solution was to add virtualisation.docker.storageDriver = "btrfs"; to my /etc/nixos/configuration.nix
Which according to the docker docs should equate to adding the following to /etc/docker/daemon.json in most other distros:
{
"storage-driver": "btrfs"
}
I was able to solve the problem by disabling the firewalld
systemctl disable firewalld
systemctl stop firewalld

attempt to change docker data-root fails - why

I am trying to set my docker storage dir as other than default, something I've done on other machines:
/etc/docker/daemon.json:
{
"data-root": "/mnt/x/y/docker_data"
}
where the storage dir looks like
jeremyr#snorble:~$ ls -ltr /mnt/x/y
total 4
drwxrwxrwx 11 jeremyr 5001 122 Mar 19 08:14 docker_data
with the daemon.json file in place, sudo systemctl restart docker hits Job for docker.service failed (without that daemon.json, docker restarts fine and docker run hello-world runs fine) . with the daemon.json in place, journalctl -xn shows
Mar 25 14:20:33 bolt88 systemd[1]: docker.service start request repeated too quickly, refusing to start.
Mar 25 14:20:33 bolt88 systemd[1]: Failed to start Docker Application Container Engine.
-- Subject: Unit docker.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has failed.
--
-- The result is failed.
Mar 25 14:20:33 bolt88 systemd[1]: Unit docker.service entered failed state.
Mar 25 14:20:34 bolt88 sudo[23961]: jeremyr : TTY=pts/18 ; PWD=/home/jeremyr ; USER=root ; COMMAND=/bin/journalctl -xn
Mar 25 14:20:34 bolt88 sudo[23961]: pam_unix(sudo:session): session opened for user root by jeremyr(uid=0)
while systemctl status docker.service just shows code=exited, status=1/FAILURE
and in dmesg I see this:
1547:[Mon Mar 25 14:21:41 2019] aufs au_opts_verify:1570:dockerd[20714]: dirperm1 breaks the protection by the permission bits on the lower branch
1548-[Mon Mar 25 14:21:41 2019] device veth34d1dfd entered promiscuous mode
1549-[Mon Mar 25 14:21:41 2019] IPv6: ADDRCONF(NETDEV_UP): veth34d1dfd: link is not ready
1550-[Mon Mar 25 14:21:41 2019] IPv6: ADDRCONF(NETDEV_CHANGE): veth34d1dfd: link becomes ready
1551:[Mon Mar 25 14:21:41 2019] docker0: port 1(veth34d1dfd) entered forwarding state
1552:[Mon Mar 25 14:21:41 2019] docker0: port 1(veth34d1dfd) entered forwarding state
1553:[Mon Mar 25 14:21:41 2019] docker0: port 1(veth34d1dfd) entered disabled state
1554-[Mon Mar 25 14:21:41 2019] device veth34d1dfd left promiscuous mode
1555:[Mon Mar 25 14:21:41 2019] docker0: port 1(veth34d1dfd) entered disabled state
1556-[Mon Mar 25 14:21:59 2019] systemd-sysv-generator[20958]: Ignoring creation of an alias umountiscsi.service for itself
Docker version 17.05.0-ce, build 89658be, on a debian 8.8 setup .
Does anyone know why docker isn't allowing use of that dir as data-root?
TD;DR -- worked on Ubuntu 18.04 just before post
follow the instructions:
sudo systemctl stop docker
sudo rsync -axPS /var/lib/docker/ /mnt/x/y/docker_data #copy all existing data to new location
sudo vi /lib/systemd/system/docker.service # or your favorite text editor
in file docker.service find one line like this:
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
add --data-root /mnt/x/y/docker_data to it(on one line):
ExecStart=/usr/bin/dockerd --data-root /mnt/x/y/docker_data -H fd:// --containerd=/run/containerd/containerd.sock
save and quit, then
sudo systemctl daemon-reload
sudo systemctl start docker
docker info | grep "Root Dir"
last command should output: Docker Root Dir: /mnt/x/y/docker_data
that's it, should've done here.
The Too Long version, if you Do want to Read:
after some investigating, I found some outdated articles, include this one, they mentioned some confident solution, these are typical pages:
add -g option in docker.service
not working because -g and --graph Deprecated In Release: v17.05.0
add data-root in /etc/docker/daemon.json, the method tried by question author,
not working for some unknown reason
read those solution on about one dozen web pages, got the inspiration:
How To Change Docker Data Folder Configuration
not a very good solution -- not popular, , but the interesting part is below Update::
graph has been deprecated in v17.05.0 .You can use data-root instead.
Yeah, graph => data-root, and the --graph is just the long form of -g, so I tried this substitution in solution add -g option in docker.service, and Ta da ~
Something is off on the docker_data.
Solution:
remove the /etc/docker/daemon.json file.
start docker.
copy the /var/lib/docker contents to the path you've put in /etc/docker/daemon.json.
put back the file /etc/docker/daemon.json and restart docker.
Well, I'm not an expert of docker, but I see "dirperm1 breaks the protection by the permission bits on the lower branch" in your log. And I also see this.
"drwxrwxrwx 11 jeremyr 5001 122 Mar 19 08:14 docker_data"
As my understanding, docker daemon requires the access permission to the directory. Does 5001 mean "docker" group?
However, if you ran the daemon in root permission, then it shouldn't happen.
Check the docker version of your machine by
docker --version
I was facing the same issue, and it got solved after upgrading the docker to latest version which is available.
Even the documentation available on docker's official website have not mentioned anything like that.
Once you upgrade docker ,
Restart the docker by
systemctl restart docker
The error will be gone, and new changes will start reflecting.

Start Docker daemon as another user?

Installed Docker 17.x version in RHEL and we are getting below excetption.
-bash-4.2$ docker version
Client:
Version: 17.09.1-ce
API version: 1.32
Go version: go1.8.3
Git commit: 19e2cf6
Built: Thu Dec 7 22:23:40 2017
OS/Arch: linux/amd64
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.32/version: dial unix /var/run/docker.sock: connect: permission denied
-bash-4.2$
to solve this , we introduce another user group (docker-user) and we added all the users in this group. after that we ran this command and able to ran docker .
sudo systemctl stop docker
sudo systemctl start docker
cd /var/run
sudo chown :docker-user docker.sock
But we are facing another issue that whenever VM is getting restarted ,DOCKER is not running. So we decided to setup run docker as daemon process and we followed
below steps.
1. create docker.conf file under /etc/systemd/system/docker.service.d folder.
2. added this entry in docker.conf file
[Service]
ExecStart=
ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock
ExecStartPost=/bin/chown :docker-user /var/run/docker.sock
After adding this entry and we ran
1. sudo systemctl daemon-reload
2. sudo systemctl stop docker
3. sudo systemctl start docker
We are getting below exception
-bash-4.2$ sudo systemctl status docker.service
● docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/docker.service.d
└─docker.conf
Active: failed (Result: start-limit) since Wed 2018-03-28 09:10:50 PDT; 12s ago
Docs: https://docs.docker.com
Process: 23395 ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock (code=exited, status=1/FAILURE)
Main PID: 23395 (code=exited, status=1/FAILURE)
Mar 28 09:10:50 hostname systemd[1]: Failed to start Docker Application Container Engine.
Mar 28 09:10:50 hostname systemd[1]: Unit docker.service entered failed state.
Mar 28 09:10:50 hostname systemd[1]: docker.service failed.
Mar 28 09:10:50 hostname systemd[1]: docker.service holdoff time over, scheduling restart.
Mar 28 09:10:50 hostname systemd[1]: start request repeated too quickly for docker.service
Mar 28 09:10:50 hostname systemd[1]: Failed to start Docker Application Container Engine.
Mar 28 09:10:50 hostname systemd[1]: Unit docker.service entered failed state.
Mar 28 09:10:50 hostname systemd[1]: docker.service failed.
Guide me how to setup docker as daemon process
So, you have already dug in pretty good.
However, this behavior is built into Docker. For user groups, the docker daemon will allow users with the docker group to access the server (important to remember, this is exactly the same as giving root access to any users in that group!). If you wanted to specify a different group, you can start the daemon with the -g option.
Installing docker also installs a systemd service unit to run the daemon. The correct way to enable that (so that it restarts automatically) is
sudo systemctl enable docker
At this point, you didn't include enough of the journalctl logs to actually say why the daemon is not starting for you- if it is an option, I would try starting over since I don't know everything you have messed with, but if that is not an option the journalctl logs will likely explain the problem (probably that the user 'docker' no longer has access to the socket after you chowned it, but that is just a guess)

Failed to start Docker Application Container Engine

I am new to Docker, so don't have much idea about it.
I tried restarting Docker service using command
service docker restart
As the command was taking too much of time I did a CTL+C
Now I am not able to start docker deamon
Any docker command gives following op
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
I tried starting Docker deamon using
systemctl start docker
But it outputs:
Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.
Output of command
**systemctl status docker.service**
`● docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/docker.service.d
└─docker.conf, http-proxy.conf, https-proxy.conf
Active: failed (Result: exit-code) since Mon 2018-03-05 17:17:54 IST; 2min 23s ago
Docs: https://docs.docker.com
Process: 11331 ExecStart=/usr/bin/dockerd --graph=/app/dockerRT (code=exited, status=1/FAILURE)
Main PID: 11331 (code=exited, status=1/FAILURE)
Memory: 76.9M
CGroup: /system.slice/docker.service
└─4593 docker-containerd-shim 3bda33eac892d14adda9f3b1fc8dc52173e26ce60ca949075227d903399c7517 /var/run/docker/libcontainerd/3bda33eac892d14adda9f3b1fc8dc52173e26c...
Mar 05 17:17:05 hj-fsbfsd9761.persistent.co.in systemd[1]: Starting Docker Application Container Engine...
Mar 05 17:17:05 hj-fsbfsd9761.persistent.co.in dockerd[11331]: time="2018-03-05T17:17:05.126009059+05:30" level=info msg="libcontainerd: new containerd process, pid: 11337"
Mar 05 17:17:06 hj-fsbfsd9761.persistent.co.in dockerd[11331]: time="2018-03-05T17:17:06.346599571+05:30" level=warning msg="devmapper: Usage of loopback devices is ...section."
Mar 05 17:17:10 hj-fsbfsd9761.persistent.co.in dockerd[11331]: time="2018-03-05T17:17:10.889378989+05:30" level=warning msg="devmapper: Base device already exists an...ignored."
Mar 05 17:17:10 hj-fsbfsd9761.persistent.co.in dockerd[11331]: time="2018-03-05T17:17:10.976695025+05:30" level=info msg="[graphdriver] using prior storage driver \"...mapper\""
Mar 05 17:17:54 hj-fsbfsd9761.persistent.co.in dockerd[11331]: time="2018-03-05T17:17:54.312812069+05:30" level=fatal msg="Error starting daemon: timeout"
Mar 05 17:17:54 hj-fsbfsd9761.persistent.co.in systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
Mar 05 17:17:54 hj-fsbfsd9761.persistent.co.in systemd[1]: **Failed to start Docker Application Container Engine.**
Mar 05 17:17:54 hj-fsbfsd9761.persistent.co.in systemd[1]: Unit docker.service entered failed state.
Mar 05 17:17:54 hj-fsbfsd9761.persistent.co.in systemd[1]: docker.service failed.
Hint: Some lines were ellipsized, use -l to show in full.
journalctl -xe
loop: Write error at byte offset 63585648640, length 4096.
How would I be able to start Docker without losing any containers and using previous configurations?
I had the same issue (Fedora 30 x86_64, kernel 5.2.9) and it turned out that being connected to a VPN was the problem. Apparently having a changed gateway address causes an "Error initializing network controller" error which I was able to see when I tried starting docker via sudo dockerd instead of sudo systemctl start docker.
I found the note here about the VPN being a possible problem, disconnecting immediately allowed me to start docker with systemctl start docker.
"Failed to start Docker Application Container Engine" is a general error message.
You should inspect journal for more details:
journalctl -eu docker
In my case it was: "error initializing graphdriver: /var/lib/docker contains several valid graphdrivers: devicemapper, overlay2"
Changing graphdriver to overlay2, fixed it:
$ sudo systemctl stop docker
$ vi /etc/docker/daemon.json # Create the file if it does not exist, and add:
{
"storage-driver": "overlay2"
}
$ sudo systemctl start docker
$ systemctl status docker.service # Hopefully it's running now
I removed the file /etc/docker/daemon.json and started it with sudo systemctl start docker and it worked!!
For the googlers:
For me what worked was doing a killall dockerd and a sudo rm /var/run/docker.pid
I got the error message that recommended that from running dockerd
I ran into this too but all I did after receiving the error was sudo systemctl start docker and then ran sudo systemctl status docker again and that took care of it while on a vpn.
You may have the issue with the current docker installation.
If you don't have much done already you may want to try to reinstall using the install script provided by Docker: https://docs.docker.com/install/linux/docker-ce/ubuntu/#install-using-the-convenience-script this will help you to investigate the errors.
I faced the same problem, in my case the disk was full. I removed docker volumes from /var/lib/docker/volumes/ and started docker with sudo systemctl start docker.

Resources