Docker-in-Docker issue.

[monokal]

Hey! Thanks for the work you'd done getting systemd running in an Ubuntu container. I'm trying to utilise what you've done using a a container within a container (Chef/Kitchen testing) and using the test container documented in the README I get the following error:

[root@698c28dc0f10 ~]# docker logs 69d925db484b
The systemd cgroup hierarchy is already mounted at /sys/fs/cgroup/systemd.
Your Docker host is now configured for running systemd containers!
[root@698c28dc0f10 ~]# docker run -d --name systemd --security-opt seccomp=unconfined --tmpfs /run --tmpfs /run/lock -v /sys/fs/cgroup:/sys/fs/cgroup:ro -t solita/ubuntu-systemd
7675be4a3fb0440c834739f7af790b4a4ca58b896769b065c4c0ca0a8edaf26e
[root@698c28dc0f10 ~]# docker logs systemd
systemd 229 running in system mode. (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD -IDN)
Detected virtualization docker.
Detected architecture x86-64.

Welcome to Ubuntu 16.04.2 LTS!

Set hostname to <7675be4a3fb0>.
Initializing machine ID from random generator.
Cannot determine cgroup we are running in: No medium found
Failed to allocate manager object: No medium found
[!!!!!!] Failed to allocate manager object, freezing.
Freezing execution.

[noidi]

Unfortunately I don't have much experience with Docker-in-Docker nor the time to investigate this issue. If you can come up with a change to solita/ubuntu-systemd that fixes the problem, I'd be happy to merge it and credit you as a contributor.

I don't know the details of your situation but, as a workaround, perhaps you could start sibling containers instead of child containers? (See "The solution" at the end of the article.) I've used that approach successfully when I've needed to use Docker in a container.

[monokal]

Thanks for the reply. I'll let you know what I come up with.

…

On 25 July 2017 at 10:47, Timo Mihaljov ***@***.***> wrote: Unfortunately I don't have much experience with Docker-in-Docker nor the time to investigate this issue. If you can come up with a change to solita/ubuntu-systemd that fixes the problem, I'd be happy to merge it and credit you as a contributor. I don't know the details of your situation but, as a workaround, perhaps you could start sibling containers <https://jpetazzo.github.io/2015/09/03/do-not-use-docker-in-docker-for-ci/> instead of child containers? (See "The solution" at the end of the article.) I've used that approach successfully when I've needed to use Docker in a container. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#10 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE6NkjhnQ6NWBe9uNzvQpL5sGFXTvSbRks5sRbmwgaJpZM4OiMaI> .