Running systemctl in container fails with "Failed to get D-Bus connection"

[daviddavis]

I searched Issues and while I found other bugs that seemed similar, I couldn't tell if they were exactly the same as this so I apologize if this is a repeat.

After following the steps on this blog to setup docker on Fedora, when you run systemctl you get an error about failing to connect to dbus.

bash-4.2# systemctl list-units
Failed to get D-Bus connection: No connection to service manager.

Docker version: docker-io-0.6.3-3.devicemapper.fc19.x86_64
OS: Fedora 19 (Schrödinger’s Cat)

[jpetazzo]

How did you start the container exactly?
It looks like you started an "application container", as opposed to a "machine container".
An "application container" just runs a specific process (or group of processes); essentially it just runs what you need.
A "machine container" will run a full init, possibly with ssh, syslog, etc.
If you start an application container, it doesn't have a real init process, and since systemctl talks to the init process... you get the idea :-)

[daviddavis]

I tried docker run -i -t 366ff524eea0 /bin/bash and I also tried:

docker ps -a # find the container
docker start 9e5f23150755
docker attach 9e5f23150755

[daviddavis]

I'm guessing both of those are app containers. How do I get/start a machine container?

[jpetazzo]

The idea is to "docker run -t -i /sbin/init".

However:

• when running Ubuntu images, a number of shortcomings in Upstart will get in the way; efforts to work around them are documented on Ubuntu/Upstart issues as a container/full machine #2276
• I don't know if peple have tried to run Fedora machine containers

This is an area which we want to support, but not so many people are working on it right now; so if you want to investigate and report your findings, that will be very helpful.

[daviddavis]

So I ran docker run -t -i -d f19 /sbin/init and then attach but the attach just hung. I will look into it more later.

[chenyf]

hi, @daviddavis , what's your latest result?

[daviddavis]

@chenyf I haven't had time to look into this. I'm fine with closing this out.

[kiorky]

@jpetazzo for #2276, those are not workarounds but fixes ;)

[creack]

Closing in favor of #2276.

@daviddavis Please feel free to reopen the issue if/when needed.

[xyproto]

This error also happens here when attempting to start sshd with systemctl start sshd on an Arch Linux container. Running /sbin/init first only hangs.

Edit: This is my very first Dockerfile and I'm new to Docker, so it is fully possible that there is a command I should or should not have run: http://ix.io/d2l

[michaelneale]

@xyproto the RUN statements only happen in the building container - not the image that results - you need to have them in ENTRYPOINT or CMD. BTW what arch image did you use with this?

[xyproto]

Thank you, michaelneale. I'll try using CMD instead. (Seems like other tutorials for setting up ssh on distros that use systemd often involve running sshd directly, btw).

[michaelneale]

@xyproto yes I am trying with arch myself (michaelneale/archbase)- that I bootstrapped. With systemd you need to have it setup to launch the services so you get in - and the one process docker bootstraps is init (and blocks) - to get in the container you will need ssh (or perhaps nsenter could work).

[etworker]

I met the same problem when running systemctl in centos docker.
Official centos7 image has no systemctl, so i download and build it, everything seems ok.

here is the error result:

[root@85287f97016e systemd-216]# systemctl --version
systemd 216
-PAM -AUDIT -SELINUX +IMA -APPARMOR +SMACK +SYSVINIT -LIBCRYPTSETUP -GCRYPT -GNUTLS -ACL +XZ -LZ4 -SECCOMP -BLKID -ELFUTILS -KMOD -IDN
[root@85287f97016e systemd-216]# systemctl
Failed to get D-Bus connection: Unknown error -1
[root@85287f97016e systemd-216]# systemctl list-units
Failed to get D-Bus connection: Unknown error -1

here is the kernel version.
[root@85287f97016e systemd-216]# uname -a
Linux 85287f97016e 3.10.0-123.13.2.el7.x86_64 #1 SMP Thu Dec 18 14:09:13 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

So the systemctl can not run inside docker, right? thanks!