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

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:

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 mentioned in the official documentation of docker Post-installation steps for Linux.

Ubuntu 16.04 users can follow these steps:

Inside file /lib/systemd/system/docker.service change:

ExecStart=/usr/bin/dockerd fd://

to

ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375

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

DOCKER_OPTS=

to

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

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

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

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.

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.

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:

After doing the above steps.

As you can see, it worked:)

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.

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

here's the solution which works for me on Linux

systemctl start docker.

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

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.

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.

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

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

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

service docker start

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

This issue can be resolved permanently by running 1. systemctl enable docker 2. service docker start

I had this problem after closing docker while 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".

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

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.

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

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

Use docker start <your_container_name>

Then connect to database by using mssql -u <yourUsername> -p <yourPassword>

If you get an error in the first step then the docker is running and go with the second step.

Note: I use Mac as my primary OS and this might be the same answer for Unix based OSs. If not! Sorry in advance.

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

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

For everyone who is having problems with Docker at the time of installation.

An error pointing to a failure in the docker service, do the commands below.

$ sudo apt update

$ sudo apt install apt-transport-https ca-certificates curl gnupg2 software-properties-common

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

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

$ sudo apt update

$ apt-cache policy docker-ce

$ sudo apt install docker-ce

It's worked for me:

sudo systemctl unmask docker
sudo systemctl start docker

In root mode, run the command systemctl start docker

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

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.

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

sudo /etc/init.d/docker start

Just restarting the system worked for me. It might be a temporary issue

This works fine for me..!

service docker restart

Easy way to fix this issue, try this

sudo su
systemctl start docker
systemctl enable docker
systemctl restart docker

I had the same issue. In my case, VPN was the culprit. Turning off the VPN helped with the successful installation.

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.

Just adding to the knowledge base. I found this video helpful. I do not have DOCKER_HOST defined. I do have a /etc/wsl.conf that has:

[automount]
root = /
options = "metadata"

After Restarting a few times docker hello-world worked.

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

For those fresh installing & trying to running docker on RaspberryPi (RPi) like me, I needed to reboot my RPi 4B+ to resolve this issue and actually run the docker daemon.

By the time of writing this contribution this great manual does mention the necessity to reboot RPi, but only after setting "Non root-user to the Docker Group".

HTH, should someone miss this like me..

If you are trying to install docker with wsl 2 linux subsystem in windows, please read this document and check whether this command is executed:

wsl.exe --set-version (distro name) 2

and also check in your Windows OS docker->settings->Resources->Enable integration with additional distros: are checked on and restarted.

It happens by the docker is not started yet.

Please check the docker status

$ sudo systemctl status docker

Then start and enable the docker and recheck the status

$ sudo systemctl start docker && sudo systemctl enable docker && sudo systemctl status docker

Thats it. Now the last step for checking the docker is working fine

$ sudo docker run hello-world

I didn't see this solution mentioned, so I'll post it in case it might help someone. I was running into this error on my MacOS machine. The reason was that I had the DOCKER_HOST environment variable set in my dotfiles. Unsetting it through unset DOCKER_HOST did the trick. I found the tip in the official docker for Mac documentation: https://docs.docker.com/desktop/mac/troubleshoot/#workarounds-for-common-problems.

if you are using MAC so just type docker in finder it will automatically resolve.

On Ubuntu 20.04 and Docker version 20.10.11,as a non root user, Running:

sudo service docker start

Then checking the status

sudo service docker status

Shows

* Docker is running

But trying any docker command such as

docker images

Shows the same error

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

Running the below solves it

sudo service docker restart

Restart solved it, while start did not

for linux run

sudo dockerd

However, if you use Docker Client for mac it won't work. try the below code

$socat TCP-LISTEN:2376,reuseaddr,fork UNIX-CLIENT:/var/run/docker.sock

https://forums.docker.com/t/using-pycharm-docker-plugin-with-docker-beta/8617/9

That workaround opens port 2376 to the world... as TLS isn't enabled, this is a bad idea as anyone on the same network can hijack your docker daemon

Just refer this video on youtube, I have been struggling since last 2 days nothing helped, but, this video saved my life!