failed to create symbolic link

[BrendanBall]

I used your dind image the other day, but when I tried using it just now (after downloading the lastest version) it doesn't work anymore. it says
ln: failed to create symbolic link '/sys/fs/cgroup/systemd/name=systemd': Operation not permitted
and results in more erros:
ERRO[0000] [graphdriver] prior storage driver "btrfs" failed: prerequisites for driver not satisfied (wrong filesystem?)

System:
docker:
Client:
Version: 1.8.1
API version: 1.20
Go version: go1.4.2
Git commit: d12ea79
Built: Thu Aug 13 02:40:42 UTC 2015
OS/Arch: linux/amd64

Server:
Version: 1.8.1
API version: 1.20
Go version: go1.4.2
Git commit: d12ea79
Built: Thu Aug 13 02:40:42 UTC 2015
OS/Arch: linux/amd64

OS: Ubuntu 15.04
kernel: 3.19.0-15-generic

[jpetazzo]

There is now an official docker:dind image upstream! I invite you to test it, since it is actively maintained. Thank you!

[htakimok]

Hi @jpetazzo , i encountered the same issue.
i run a container with docker:dind, but when I use docker attach command to attach the container. it just blocked.
so i build a new image with open-ssh installed based on docker:dind..
then i ssh to the container, the docker daemon not start
i run /etc/init.d/docker start, the output is ok.
but the /etc/init.d/docker status command shows it's still not running.
so i run /usr/bin/docker -d, i got the following error
ERRO[0000] [graphdriver] prior storage driver "btrfs" failed: prerequisites for driver not satisfied (wrong filesystem?)
FATA[0000] Error starting daemon: error initializing graphdriver: prerequisites for driver not satisfied (wrong filesystem?)

so what's the solution?

[jpetazzo]

What is the exact command line that you are running? Thank you!

[htakimok]

@jpetazzo
i run
/usr/bin/docker -d

[tianon]

Can you share your dockerfile also? The docker:dind images don't have an init script for docker.

[htakimok]

@tianon @jpetazzo
question description with markdown.
I run a container with docker:dind image named realDocker.

root@ubuntu:~# docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                              NAMES
c894b6aedf85        docker:dind         "dockerd-entrypoint.s"   23 hours ago        Up 45 seconds       2375/tcp, 0.0.0.0:4445->4444/tcp   realDocker

But when I use docker attach command to attach the container. it just blocked until I press ctrl+c to stop.

root@ubuntu:~# docker attach realDocker 

^Ctime="2015-09-18T06:09:30.561515741Z" level=info msg="Processing signal 'interrupt'" 

I don't know why.
so i build a new image with open-ssh installed based on docker:dind.
My dockerfile:

# Pull base image.
FROM jpetazzo/dind


# Install openssh-server
RUN apt-get update && apt-get install -y openssh-server
RUN mkdir /var/run/sshd
RUN echo 'root:root' | chpasswd
RUN sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config

# SSH login fix. Otherwise user is kicked off after login
RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd

ENV NOTVISIBLE "in users profile"
RUN echo "export VISIBLE=now" >> /etc/profile

EXPOSE 22
CMD ["/usr/sbin/sshd", "-D"]

then i ssh to the container, but i find the docker is not running.

root@ubuntu:~# docker ps
CONTAINER ID        IMAGE               COMMAND               CREATED             STATUS              PORTS                   NAMES
c83c53ab5f63        hp02                "/usr/sbin/sshd -D"   20 hours ago        Up 3 seconds        0.0.0.0:32781->22/tcp   hp2
root@ubuntu:~# ssh root@127.0.0.1 -p 32781
The authenticity of host '[127.0.0.1]:32781 ([127.0.0.1]:32781)' can't be established.
ECDSA key fingerprint is 7c:66:35:c7:6a:f5:2d:e9:6e:89:55:b6:d5:cf:40:84.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[127.0.0.1]:32781' (ECDSA) to the list of known hosts.
root@127.0.0.1's password: 
Welcome to Ubuntu 14.04.3 LTS (GNU/Linux 3.13.0-32-generic x86_64)

 * Documentation:  https://help.ubuntu.com/
Last login: Thu Sep 17 10:03:16 2015 from 172.17.42.1
root@c83c53ab5f63:~# 
root@c83c53ab5f63:~# docker ps
Cannot connect to the Docker daemon. Is 'docker -d' running on this host

and start docker service manually, i got the following error:

root@c83c53ab5f63:~# /usr/bin/docker -d
ERRO[0000] [graphdriver] prior storage driver "btrfs" failed: prerequisites for driver not satisfied (wrong filesystem?) 
FATA[0000] Error starting daemon: error initializing graphdriver: prerequisites for driver not satisfied (wrong filesystem?)

[jpetazzo]

You need to read the documentation: https://hub.docker.com/_/docker/

Once your readDocker container is running, you can do:

docker run --link readDocker:docker docker ps

But check the doc for more details. Thank you!