Cannot connect to the Docker daemon at unix:/var/run/docker.sock. Is the docker daemon running?

368
votes

I have applied every solution available on internet but still I cannot run Docker.

I want to use Scrapy Splash on my server.

Here is history of commands I ran.

docker run -p 8050:8050 scrapinghub/splash
sudo docker run -p 8050:8050 scrapinghub/splash
sudo usermod -aG docker $(whoami)
sudo docker run -p 8050:8050 scrapinghub/splash
newgrp docker
sudo docker run -p 8050:8050 scrapinghub/splash
reboot
sudo docker run -p 8050:8050 scrapinghub/splash
docker run -p 8050:8050 scrapinghub/splash

You can see I tried to restart my server as well, but it didnt help.

see output of ps -aux | grep docker

root@mani:/var/www/html# ps aux | grep docker
root      8524  0.0  0.8 127904 13964 ?        Ssl  17:21   0:00 /usr/bin/dockerd --raw-logs
root      8534  0.0  0.3  90588  5012 ?        Ssl  17:21   0:00 docker-containerd -l unix:///var/run/docker/libcontainerd/docker-containerd.sock --metrics-interval=0 --start-timeout 2m --state-dir /var/run/docker/libcontainerd/containerd --shim docker-containerd-shim --runtime docker-runc
root      8543  0.0  0.0   8812   764 pts/1    S+   17:21   0:00 grep --color=auto docker
root     16356  0.0  0.0  17200   964 pts/1    S    17:14   0:00 newgrp docker
root     20080  0.0  0.0  17200   964 pts/1    S    17:06   0:00 newgrp docker
root     30221  0.0  0.0  17200   964 pts/1    S    17:09   0:00 newgrp docker
30
linuxubuntudockerubuntu-14.04
If you run ps aux | grep docker, do you see the daemon process running? - Rome_Leader
Possible duplicate: stackoverflow.com/questions/21871479/… - BMitch
@Rome_Leader see the output in my question ... - Umair Ayub
try this : sudo service docker restart - Haythem ROUIS
you can see the status of you docker deamon using this : sudo service docker status check if it is active - Haythem ROUIS

30 Answers

306
votes

You can try out this:

systemctl start docker

It worked fine for me.

P.S.: after if there is commands that you can't do without sudo, try this:

gpasswd -a $USER docker
148
votes

Just Run

sudo dockerd

dockerd is the daemon service for docker containers, because it is not running in background we're not able to take any actions related to the service, which needs be restarted.

73
votes

You can get this error if docker doesn't shut down cleanly. The following answer is for the docker snap package.

Run snap logs docker and look for the following:

Error starting daemon: pid file found, ensure docker is not running or delete /var/snap/docker/179/run/docker.pid

Deleting that file and restarting docker worked for me.

rm /var/snap/docker/<your-version-number>/run/docker.pid
snap stop docker
snap start docker

Make sure to replace ‍‍‍‍<your-version-number>‍ with the appropriate version number.

44
votes

Easy way to fix this issue, try this

sudo su
systemctl start docker
systemctl enable docker
systemctl restart docker
40
votes

I just hit this after doing a fresh install of DOCKER from the main docs. The problem for me was that immediately after the install, the service is not running.

These commands will help you to make sure docker is up and running for your run command to find it: 

$ sudo service --status-all 
$ sudo service docker start
$ sudo service docker start
29
votes

First, try with sudo, as the current user may not have access permissions to communicate to docker daemon i.e. /var/run/docker.sock

If its still not working, then, after the installation, simply stop the docker daemon as,

$ sudo service docker stop

And, run the following command to start the daemon in background,

$ sudo nohup docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock

To make working with Docker easier, you should add your username to the Docker users group. Adding a user to the group can be done with the command below

$ sudo usermod -aG docker $USER

Also, this step is mention at official documentation of docker Post-installation steps for Linux (https://docs.docker.com/engine/installation/linux/linux-postinstall/)

The Ubuntu 16.04 users can follow these steps,

Inside file /lib/systemd/system/docker.service change: ExecStart=/usr/bin/dockerd fd:// with ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375

Inside file /etc/init.d/docker change:

DOCKER_OPTS= with DOCKER_OPTS="-H ****tcp://0.0.0.0:2375 "

and then restart your machine. And, start playing with docker.

22
votes

It's worked for me:

sudo systemctl unmask docker
sudo systemctl start docker
21
votes

enter image description here

I just simply forget running the Docker Desktop in my mac, after running Docker Desktop, you will be good to go.

16
votes

This usually happened if you haven't stopped docker probably.

To resolve

service docker stop
cd /var/run/docker/libcontainerd
rm -rf containerd/*
rm -f docker-containerd.pid
service docker start

then "docker run...." to download your image and start the container as usual

13
votes

This works fine for me..!

service docker restart

7
votes

I'm running on root and tried below, it worked:

service docker start

export DOCKER_HOST="tcp://0.0.0.0:2375"
7
votes

I had this problem after closing docker will pulling a container docker pull mongo. At first I was getting weird errors so I purged docker sudo apt-get purge docker.io and reinstalled sudo apt-get install docker.io... all of this did nothing. I couldn't even run the hello-world container. The correct fix for me at least was:

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

After this I could pull mongo and run hello world.

Cheers!

7
votes

I guess if you are using WSL with GUI, then you could just try

sudo /etc/init.d/docker start
6
votes

here's the solution which works for me on Linux

systemctl start docker.

5
votes

I also received the error message below, after installing the docker and running: docker run hello-world #Cannot connect to the Docker daemon at unix: /var/run/docker.sock. Is the docker daemon running?

Here's a solution, what worked for me. Environment

  • Windows 10 (Don't forget to enable on windows: Settings> Update and Security> Developer mode)
  • Ubuntu 18.04 LTS
  • Docker Desktop version 2.3.0.2 (45183)
    • Enable in Docker Desktop: Expose daemon on tcp: // localhost: 2375 without TLS
    • Docker Desktop must also be running (connected to Docker Hub ... just log in)

After installing ubuntu, update the repository

sudo apt-get update

To use a repository over HTTPS

sudo apt-get install apt-transport-https ca-certificates curl gnupg-agent software-properties-common

Add the official Docker GPG key:

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

Make sure you now have the key with the fingerprint

sudo apt-key fingerprint 0EBFCD88

Update the repository

sudo apt-get update

Update the docker repository

sudo add-apt-repository "deb [arch = amd64] https://download.docker.com/linux/ubuntu $ (lsb_release -cs) stable "

Update the repository again

sudo apt-get update

Command to install the docker in version: 5: 18.09.9 ~ 3-0 ~ ubuntu-bionic

sudo apt-get install docker-ce = 5: 18.09.9 ~ 3-0 ~ ubuntu-bionic docker-ce-cli = 5: 18.09.9 ~ 3-0 ~ ubuntu-bionic containerd.io

Command to set the DOCKER_HOST

export DOCKER_HOST="tcp://0.0.0.0:2375"

Note: put the command above in your profile to start with the ubunto ex: echo "export DOCKER_HOST="tcp://0.0.0.0:2375"" >> ~/.bashrc

Add user to the docker group

sudo usermod -aG docker $USER

Restart ubuntu

(Close and open the ubuntu window again) or run:

source ~/.bashrc

Testing the installation (DO NOT use more sudo before docker commands (it will give an error), the user "root" has already been included in the docker group)

docker run hello-world

The message below should be displayed

Hello from Docker! This message shows that your installation appears to be working correctly.

Note: if it fails, run the command again:

export DOCKER_HOST="tcp://0.0.0.0:2375"

Reference: https://docs.docker.com/engine/install/ubuntu/ Session: INSTALL DOCKER ENGINE

#For other versions of the docker that can be installed with ubuntu, see the repository using the command below: apt-cache madison docker-ce

Then install the desired version of the docker:

sudo apt-get install docker-ce = <VERSION_STRING> docker-ce-cli = <VERSION_STRING> containerd.io
4
votes

Make sure information in this path /etc/docker/daemon.json

{
  "registry-mirror": [
    "https://registry.docker-cn.com"
  ],
  "insecure-registries": [
    "192.168.199.100:5000"
  ]
}

delete 

"insecure-registries": [
    "192.168.199.100:5000"
]

and runs well enter image description here

3
votes

I was trying to run docker(just installed) in an instance of AWS when the message appears. I just write sudo service docker start and works fine for me.

Also see AWS with Docker

3
votes

This exception comes when the service of docker is not running or the logged in user dont have the permission to access docker and generally it comes in RedHat

Using below command should resolve the issue

sudo service docker start

enter image description here

2
votes

use this in ubuntu export DOCKER_HOST=tcp://localhost:2375

2
votes

export DOCKER_HOST=tcp://localhost:2375 is perfect for anyone who doesn't have sudo access and the user doesn't have access to unix:///var/run/docker.sock

2
votes

None of the current answers worked for my version of this error. I'm using the desktop version of Ubuntu 18. The following two commands fixed the issue.

sudo snap connect docker:home :home

sudo snap start docker

2
votes

In root mode, run the command systemctl start docker

And afterwards, you can check the status by running systemctl status docker

1
votes

I had the same problem for gitlab CI running node:lts image:

  • I just restarted the docker daemon and restart the container, it worked for me.
1
votes

This worked for me, It might just work for you if you are using Ubuntu 16 or 18 (14 may also work). Easy to give a try:

Go to Ubuntu Software, type in Docker. Uninstall docker (108 mb) if it is preinstalled there. Install docker Now run the commands and see if the same error comes

The error:

enter image description here

After doing the above steps. enter image description here

As you can see, it worked:)

1
votes

I faced same issue on Linux when I installed docker using yum (yum install docker).

Resolution: download docker binary from official site: docker install, unpack and follow the installation steps.

1
votes

It could be related to no disk space left on the hard drive. Make sure you have space left on the device, Docker can't start up if there isn't any space left.

1
votes

I installed docker from snap repository. So I also had to start from snap (running Ubuntu).

sudo snap start docker

Otherwise you can also install it from their repositories.

1
votes

I had this problem when docker was started after my terminal was started. Restarting the terminal or the process hosting the terminal (such as vscode) resolved the issue.

1
votes

This might be a bit late for you but hope it will help someone find their way through the docker jungles. The problem might be coming from a tcp port binding issue verify if this file exists

/etc/systemd/system/docker.service.d

this is the default UNIX socket listening override file. The file might actauly be empty, but i find that the fact that it exists sometimes causes some headaches like what you faced. if it exists 1. then 2. if not just go straight to 2.

1. $ sudo rm -rf /etc/systemd/system/docker.service.d

2. $ sudo systemctl deamon-reload

I find that some of the recommendations here overlook the error being in the actual daemon failing to load

A good friend when playing with docker is

$ systemctl status docker.service
0
votes

For me the solution was to simply make sure I had installed the correct Docker package. For example, for Ubuntu the depreciated packages are:

  • docker
  • docker-engine
  • docker.io
  • containerd
  • runc

For installation check https://docs.docker.com. Instructions are provided for Ubuntu, CentOS, Debian and Fedora at the time of writing.