Ubuntu – How to run systemctl command inside docker container

dbusdockersystemd

I would like to run a docker container which will have the ability to run systemctl commands on its host.

Following this question I didn't find a solution that would work for me.

I have no hard limits on the docker base image, so using ubuntu-16.04 docker image for an ubuntu-16.04 host and ubuntu-18.04 docker image for an ubuntu-18.04 host is totally acceptable.

Best Answer

After some investigation I was able to run a docker container with the ability to run systemctl command.

The following worked when running on an ubuntu:16.04 host:

sudo docker run --privileged -v /run/systemd/system:/run/systemd/system -v /bin/systemctl:/bin/systemctl -v /var/run/dbus/system_bus_socket:/var/run/dbus/system_bus_socket -it ubuntu:16.04 systemctl

sudo docker run --privileged -v /run/systemd/system:/run/systemd/system -v /var/run/dbus/system_bus_socket:/var/run/dbus/system_bus_socket -it ubuntu:16.04 systemctl

And on ubuntu:18.04 host:

sudo docker run --privileged -v /run/systemd/system:/run/systemd/system -v /var/run/dbus/system_bus_socket:/var/run/dbus/system_bus_socket -it ubuntu:18.04 systemctl

Since systemctl doesn't come with this image

Related Solutions

Docker – Can Snappy Ubuntu Core Run as a Guest Inside Docker?

Yes, you can: Snappy is just a stripped down version of Ubuntu, and Ubuntu works inside Docker. The fact that Snappy does not appear inside the public Docker repository implies that you have to do things manually.

First, get the latest image:
```
wget http://cdimage.ubuntu.com/ubuntu-core/preview/ubuntu-core-alpha-02_amd64-virt.img
```
This file is a QCOW2 image meant for QEMU/KVM, but we can extract its contents for Docker too.
In order to access the files inside a QCOW2 image, you'll need qemu-nbd, so install it and run:
```
qemu-nbd -c /dev/nbd0 ubuntu-core-alpha-02_amd64-virt.img
```
This command will create a "virtual disk" named /dev/ndb0, with "virtual partitions" named /dev/ndb0pX. Use fdisk -l /dev/nbd0 to get an idea of what partitions are inside the QCOW2 image.
The partition you are interested in is /dev/ndb0p3, so mount it:
```
mount /dev/ndb0p3 /somewhere
```
You are almost done! Just follow Docker's guide on custom base images:
```
tar -C /somewhere -c . | docker import - snappy
```

Now you are ready to create your Snappy images on top of that base image. For example, I created a snappy_test image with the xkcd-webserver app installed. Here's the Dockerfile I used:

FROM snappy:latest
RUN snappy install xkcd-webserver
EXPOSE 80

Ubuntu – what’s the difference between base os ubuntu and image ubuntu

For convenience, there are default base operating systems.

For the Oracle Virtual Box driver, this base operating system is the boot2docker.iso.
For drivers used to connect to cloud providers, the base operating system is Ubuntu 12.04+

Those are two different environments, as I described in "Container as a Service (Caas)":

the non-Linux host will use a TinyCore-based BM called boot2docker: in it you can run docker daemon and launch any container based on any image you want (ubuntu or otherwise)
the cloud hosts, that is cloud providers, the base operating system is the latest Ubuntu LTS the provider supports. Hence Ubuntu 12.04.
To use a different base operating system on a remote provider, specify the provider’s image flag and one of its available images. For example, to select a debian-8-x64 image on DigitalOcean you would supply the --digitalocean-image=debian-8-x64 flag.

In all environments, the goal is to provide a Linux kernel recent enough to support docker feature, allowing any docker image to delegate its system calls to the kernel.

Best Answer

Related Solutions

Docker – Can Snappy Ubuntu Core Run as a Guest Inside Docker?

Ubuntu – what’s the difference between base os ubuntu and image ubuntu

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