How to fix docker: Got permission denied issue

Question

I installed Docker in my machine where I have Ubuntu OS. After than I installed docker, when I run

sudo docker run hello-world

All it's ok, but I want to hide the word sudo to make more short the command.

If I write the command without the word sudo

docker run hello-world

That display the following:

docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.35/containers/create: dial unix /var/run/docker.sock: connect: permission denied.See 'docker run --help'.

It's happened the same when I try to make

docker-compose up

How can I resolve this?

Answer 1

I solve this error with the command :

$ sudo chmod 666 /var/run/docker.sock

Answer 2

lightdm and kwallet ship with a bug that seems to not pass the supplementary groups at login. To solve this, I also, beside sudo usermod -aG docker $USER, had to comment out

auth optional pam_kwallet.so
auth optional pam_kwallet5.so

to

#auth optional pam_kwallet.so
#auth optional pam_kwallet5.so

in /etc/pam.d/lightdm before rebooting, for the docker-group to actually have effect.

bug: https://bugs.launchpad.net/lightdm/+bug/1781418 and here: https://bugzilla.redhat.com/show_bug.cgi?id=1581495

Answer 3

After Docker Installation on Centos. While running below command I got below error.

[centos@aiops-dev-cassandra3 ~]$ docker run hello-world
docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.soc k/v1.40/containers/create: dial unix /var/run/docker.sock: connect: permission denied.
See 'docker run --help'.

Change Group and Permission for docker.socket

[centos@aiops-dev-cassandra3 ~]$ ls -l /lib/systemd/system/docker.socket
-rw-r--r--. 1 root root 197 Nov 13 07:25 /lib/systemd/system/docker.socket
[centos@aiops-dev-cassandra3 ~]$ sudo chgrp docker /lib/systemd/system/docker.socket
[centos@aiops-dev-cassandra3 ~]$ sudo chmod 666 /var/run/docker.sock
[centos@aiops-dev-cassandra3 ~]$ ls -lrth /var/run/docker.sock
srw-rw-rw-. 1 root docker 0 Nov 20 11:59 /var/run/docker.sock
[centos@aiops-dev-cassandra3 ~]$

Verify by using below docker command

[centos@aiops-dev-cassandra3 ~]$ docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
1b930d010525: Pull complete
Digest: sha256:c3b4ada4687bbaa170745b3e4dd8ac3f194ca95b2d0518b417fb47e5879d9b5f
Status: Downloaded newer image for hello-world:latest

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

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/

[centos@aiops-dev-cassandra3 ~]$

Answer 4

Seriously guys. Do not add Docker in your groups or modifies the socket posix (without a hardening SELinux), it's a simple way to make a root privesc. Just add an alias in your .bashrc, it's simpler and safer as : alias dc='sudo docker'.

Answer 5

1. Add current user to docker group

sudo usermod -aG docker $USER

2. Change the permissions of docker socket to be able to connect to the docker daemon /var/run/docker.sock

sudo chmod 666 /var/run/docker.sock

Answer 6

Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.40/images/json: dial unix /var/run/docker.sock: connect: permission denied

sudo chmod 666 /var/run/docker.sock

This fix my problem.