Yes I have followed steps provided here https://docs.docker.com/engine/install/ubuntu/ and https://docs.docker.com/engine/install/linux-postinstall/ and also checked this thread docker.sock permission denied
But still getting the below problem when docker is run without sudo in Ubuntu 18.04
docker run hello-world
docker: Cannot connect to the Docker daemon at unix:///run/user/1000/docker.sock. Is the docker daemon running?.
See 'docker run --help'.
It is rather frustrating as I tried multiple times.
It worked fine after deleting the below entry in .bashrc
export DOCKER_HOST=unix:///run/user/1000/docker.sock
I'm not sure how that line made it into .bashrc
Feel so stupid now. Anyway thanks!
I perform the following docker commands in the following order:
docker pull docker
docker run -ti <imgId>
https://hub.docker.com/_/docker/
Now I am inside the "docker" image for Docker
Now suppose I create a temp folder and download a Dockerfile
mkdir temp
cd temp
curl <dockerfile>
docker build .
It will tell me Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
This means that the docker service needs to be started, but as the official docker image comes on alpine linux, commands like service/systemctl are not available, so we must perform apk add openrc --no-cache to access these.
After I install it, I still cannot start the docker service.
Performing system docker start says that it cannot find docker as a service?
service: service docker does not exist
Eventually I want to build this via Jenkins.
In the build step, I perform Execute Shell
if [ -f "Dockerfile" ]; then
echo "Dockerfile exists ... removing it"
rm Dockerfile
fi
wget <dockerFile url>
docker build .
I purposely don't do the openrc on Jenkins since I want to test locally first
The image you're pulling here (with the latest tag) does not contain the docker daemon. It's meant to be used as the docker client. What you want is to first get the docker daemon running with the image tagged dind (docker in docker).
docker network create dind
docker run --privileged --name docker --network dind -v docker-client-certs:/certs/client -d docker:dind
To verify it started up and works, you can check the logs.
docker logs docker
Now you can use a client container to connect to the daemon. This is how you connect interactively to the shell, like you wanted to:
docker run -ti --network dind -e DOCKER_TLS_CERTDIR=/certs -v docker-client-certs:/certs/client:ro docker
Docker commands should work inside this container. If you do docker version, you should see the versions of both the client and the server.
Note the two containers share the same network (some examples online feature links, but those are deprecated). They also share some of the TLS certs, which are generated when starting up the dind image.
I started to experiment with the docker but have some questions regarding how to develop on it and regarding its use cases. If anyone could guide me through these questions, it will be much appreciated.
First,
As far as I understood, docker is used mainly for developing applications on custom environments, thus avoiding the tidious installation processes. This is initially my intention, why I'd like to use docker for.
I've created a docker file which builds successfuly, and which has basic C++ development tools based upon library/gcc. I want to be able to develop in this docker container as you would do on your terminal.
What I did is I created a docker image from a Dockerfile. (I can observe that it is successfully created)
docker build -t mydockerimage .
Then run the docker in detached mode.
docker run -d mydockerimage
At this point, I am notified with the ID of the docker container. However docker container does not seem to be running when I check the output of:
docker container ls
Here comes the first question, why is my docker container not running?
To my understanding, simplest way to interact with the docker container is as follows:
docker exec -it <container_id_or_name> echo "Hello from container!"
Is this true? Is this a use case of docker in which I simply can start the container and exec some Linux command on it?
Moreover, I get a permission denied on /var/lib/docker.sock when I try to execute docker commands without sudo. What am I missing here?
Thank you in advance.
Do you provide an entrypoint or CMD in your dockerfile? This will be executed inside your container and keeps the container running. You can find some details here.
In short. Docker has a default entrypoint: /bin/sh -c, but no default CMD.
Check the dockerfile of ubuntu. This has bash as CMD so it's executing /bin/sh -c bash.
$ docker run -it ubuntu bash
root#9855e779cab2:/#
This will result in an interactive shell in which you can execute commands like on an ubuntu. If you exit the container the container will stop running.
To keep a container running you can use the -d option. It will run the container in the background as a daemon:
$ docker run -d -it ubuntu bash
2606ad8e095baa0237cc30e599a26a4d727d99d47392d779fb83cd50f1a39614
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
2606ad8e095b ubuntu "bash" 18 seconds ago Up 17 seconds cranky_johnson
Now you can exec inside the container to "go inside" the container and execute ubuntu commands.
$ docker exec -it 2606ad8e095b bash
root#2606ad8e095b:/#
When you exit the container it remains running in the background.
Now we can execute your command too:
$ docker exec -it 2606ad8e095b echo "Hello from container!"
Hello from container!
This will open a bash session in your container and echo the string.
I think it's important in your case you define some entrypoint (which can also be a script) or a CMD. Probably you need something very similar to Ubuntu when you just want to use bash inside your container.
Moreover, I get a permission denied on /var/lib/docker.sock when I try to execute docker commands without sudo. What am I missing here?
This is normal. The Docker daemon currently requires root privileges. So you have to use docker with your root user or users which have root priviledges and you have to add sudo every time. You can add your user to a docker group. Every time the daemon starts, it makes the ownership of the Unix socket read/writable by the docker group. This means you can use docker without using sudo everytime when that user is inside your docker group.
To add your user to the docker group:
$ sudo groupadd docker
$ sudo usermod -aG docker $USER
$ exit
ssh back or open new shell
I tried installing the docker using the linux method.
However when the command $docker run hello-world is executed, it outputs:
docker: Cannot connect to the Docker daemon. Is the docker daemon running on this host?.
See 'docker run --help'.
What can be done about this?
First of all make sure the daemon is running:
$ps aux|grep "docker daemon"|grep -v "grep"
A) The daemon is not launched (no lines are returned by the ps)
Start the daemon that is not working:
$sudo /usr/bin/docker daemon -H unix:///var/run/docker.sock
Or start it as a service with:
$sudo /usr/sbin/service docker start
At this point the daemon is launched.
B) The daemon is launched
As shown by the ps with something like:
[..] /usr/bin/docker daemon -H unix:///var/run/docker.sock
You're good to go with your first container with a:
$sudo docker run hello-world.
sudo and docker
If you want to use docker without being sudo (this you should, though you must be aware of the security warning!) a good read of this will help you.
You have to run this command as sudo.
sudo docker run hello-world
This will give you enough privileges to perform that action.
If you want to enable your user to rung docker without sudo, then check out this answer.
I am new to docker. I have a shell script that loads data into impala and I want a docker file that runs builds an image and run the container.
I am on mac, installed boot2docker and have the DOCKER_HOST env set up.
bash-3.2$ docker info
Containers: 0
Images: 0
Storage Driver: aufs
Root Dir: /mnt/sda1/var/lib/docker/aufs
Dirs: 0
Execution Driver: native-0.2
Kernel Version: 3.15.3-tinycore64
Debug mode (server): true
Debug mode (client): false
Fds: 10
Goroutines: 10
EventsListeners: 0
Init Path: /usr/local/bin/docker
Sockets: [unix:///var/run/docker.sock tcp://0.0.0.0:2375]
I am trying to just installed a pre-built image using:
sudo docker pull busybox
I get this error:
sudo docker pull busybox
2014/08/18 17:56:19 Post http:///var/run/docker.sock/images/create?fromImage=busybox&tag=: dial unix /var/run/docker.sock: no such file or directory
Is something wrong with my docker setup?
When I do a docker pull busybox, It pulls the image and download is complete.
bash-3.2$ docker pull busybox
Pulling repository busybox
a9eb17255234: Download complete
fd5373b3d938: Download complete
d200959a3e91: Download complete
37fca75d01ff: Download complete
511136ea3c5a: Download complete
42eed7f1bf2a: Download complete
c120b7cab0b0: Download complete
f06b02872d52: Download complete
120e218dd395: Download complete
1f5049b3536e: Download complete
bash-3.2$ docker run busybox /bin/echo Hello Doctor
Hello Doctor
Am I missing something?
You don't need to run any docker commands as sudo when you're using boot2docker as every command passed into the boot2docker VM runs as root by default.
You're seeing the error when you're running as sudo because sudo doesn't have the DOCKER_HOST env set, only your user does.
You can confirm this by doing a:
$ env
Then a
$ sudo env
And looking for DOCKER_HOST in each output.
As for having a docker file that runs your script, something like this might work for you:
Dockerfile
FROM busybox
# Copy your script into the docker image
ADD /path/to/your/script.sh /usr/local/bin/script.sh
# Run your script
CMD /usr/local/bin/script.sh
Then you can run:
docker build -t your-image-name:your-tag .
This will build your docker image, which you can see by doing a:
docker images
Then, to run your container, you can do a:
docker run your-image-name:your-tag
This run command will start a container from the image you created with your Dockerfile and your build command and then it will finish once your script.sh has finished executing.
You can quickly setup your environment using shellinit
At your command prompt execute:
$(boot2docker shellinit)
That will populate and export the environment variables and initialize other features.
docker pull will fail if docker service is not running. Make sure it is running by
:~$ ps aux | grep docker
root 18745 1.7 0.9 284104 13976 ? Ssl 21:19 0:01 /usr/bin/docker -d
If it is not running, you can start it by
sudo service docker start
For Ubuntu 15 and above use
sudo systemctl start docker
On my MAC when I start boot2docker-vm on the terminal using
boot2docker start
I see the following
To connect the Docker client to the Docker daemon, please set:
export DOCKER_CERT_PATH=<my things>
export DOCKER_TLS_VERIFY=1
export DOCKER_HOST=tcp://<ip>:2376
After setting these environment variables I was able to run the build without the problem.
Update [2016-04-28] If you are using a the recent versions of docker you can do
eval $(docker-machine env) will set the environment
(docker-machine env will print the export statements)
I also got this error. Though, I did not use boot2docker but just installed "plain" docker on Ubuntu (see https://docs.docker.com/installation/ubuntulinux/).
I got the error ("dial unix /var/run/docker.sock: no such file or directory. Are you trying to connect to a TLS-enabled daemon without TLS?") because the docker daemon was not running, yet.
On Ubuntu, you need to start the service:
sudo service docker start
See also http://blog.arungupta.me/resolve-dial-unix-docker-sock-error-techtip64
For boot2docker on Windows, after seeing:
FATA[0000] Get http:///var/run/docker.sock/v1.18/version:
dial unix /var/run/docker.sock: no such file or directory.
Are you trying to connect to a TLS-enabled daemon without TLS?
All I did was:
boot2docker start
boot2docker shellinit
That generated:
export DOCKER_CERT_PATH=C:\Users\vonc\.boot2docker\certs\boot2docker-vm
export DOCKER_TLS_VERIFY=1
export DOCKER_HOST=tcp://192.168.59.103:2376
Finally:
boot2docker ssh
And docker works again
In Linux, first of all execute sudo service docker start in terminal.
If you're using CentOS 7, and you've installed Docker via yum, don't forget to run:
$ sudo systemctl start docker
$ sudo systemctl enable docker
This will start the server, as well as re-start it automatically on boot.
To setup your environment and to keep it for the future sessions you can do:
echo 'export DOCKER_HOST="tcp://$(boot2docker ip 2>/dev/null):2375";' >> ~/.bashrc
Then:
source ~/.bashrc
And your environment will be setup in every session
The first /var/run/docker.sock refers to the same path in your boot2docker virtual machine. Correcly write for windows /var/run/docker.sock
You, maybe the not the OP, but someone may have a directory called /var/run/docker.sock/ already due to how many times you hack and slash to get things right with docker (especially noobs). Delete that directory and try again.
This helped me on my way to getting it to work on Centos 7.
I have installed the docker using offline method and post server restart docker is not running.
So, I executed the below command it worked for me!
/usr/bin/dockerd > /dev/null
run the following commands, OS = CentOS / RHLE / Amazon Linux, etc.
sudo systemctl start docker
sudo systemctl enable docker
sudo systemctl status docker
chmod 777 /var/run/docker.sock