docker: x on no x

jr_bob_dobbs · 03-21-2017, 12:27 PM

So let's imagine a working installed Linux operating system. It has docker. It has no x-windows, no gui at all. Right: now get and put in a container for docker that has x-windows. Do I now have x-windows running?

pan64 · 03-22-2017, 05:49 AM

running system-wide daemons (like dbus) inside the docker container is not trivial. but you can try...

sundialsvcs · 03-27-2017, 07:49 PM

Generally, I would recommend that any application that is running within a container should never try to avail itself of any host services that are not "by definition, universal."

"X-Windows" cannot be called "universal," because "there is only one of you!"

Habitual · 03-28-2017, 10:45 AM

Quote:

Originally Posted by jr_bob_dobbs

So let's imagine a working installed Linux operating system. It has docker. It has no x-windows, no gui at all. Right: now get and put in a container for docker that has x-windows. Do I now have x-windows running?

Technically, you don't have x running.
What do you think docker is?

simosx · 04-13-2017, 06:03 AM

You can run GUI apps in an LXD container, and have them appear on your desktop with your other apps.

Here is an example:

Code:

lxc launch ubuntu:x mycontainer
lxc exec mycontainer -- apt update
lxc exec mycontainer -- apt install x11-apps

This creates a container called "mycontainer". Then, it runs a "apt updat" inside the container, then, it installs "x11-apps" which includes the "xclock" app.

You then need to be able to SSH into "mycontainer".
This means that you need to place your SSH public key in the account "ubuntu" (/home/ubuntu/.ssh/authorized_keys) in the container.
Here is how to do this:

Code:

cat ~/.ssh/id_rsa.pub | lxc exec mycontainer -- sudo --login --user ubuntu tee /home/ubuntu/.ssh/authorized_keys

Finally, let's run the "xclock" app in the container and have it appear on our desktop X.

Code:

ssh -X ubuntu@mycontainer.lxd xclock

You can expand this with more complex apps.

jr_bob_dobbs · 04-19-2017, 12:58 PM

Quote:

Originally Posted by Habitual

Technically, you don't have x running.
What do you think docker is?

Well, I must confess some confusion as to what docker is. By asking highly specific, carefully thought out ahead of time, questions I hope to build up a view of what docker actually does.

I've been researching as best as I can, but admit to a sort of conceptual block. It's the sort of thing that would be most likely resolved by actually running docker, but I've not been able to get docker working. D'oh! But that's beyond (and thus off-topic from) the (high specific) focus of this thread.

Thank you everyone for the replies.

jr_bob_dobbs · 04-19-2017, 01:01 PM

Quote:

Originally Posted by simosx

You can run GUI apps in an LXD container, and have them appear on your desktop with your other apps.

Is this something that only LXD can do, and not the other container methods?

pan64 · 04-20-2017, 01:03 AM

the problem is not the GUI itself, but the communication with other apps (like X server), using message bus (dbus daemon) and sockets (/tmp/.X11-unix/X0) which may or may not available from the container. And obviously you can have authentication related issues too.

simosx · 04-23-2017, 04:37 PM

Quote:

Originally Posted by jr_bob_dobbs

Is this something that only LXD can do, and not the other container methods?

The "ssh -X" method can be used with any Linux server that has the X11 libraries, including containers.
The instructions that I gave above, are suitable for LXD.

It is also possible to run accelerated graphics by sharing the X11 devices to the container.
I am not sure how this would be configured with docker.
The accelerated graphics are required when playing games or running other graphics-intensive apps.

Laserbeak · 05-03-2017, 12:03 AM

I don't believe the X Windows server has to be running on the server for X Windows programs to run with the DISPLAY set to another host.

pan64 · 05-03-2017, 12:18 AM

there are a lot of different approaches, yes, and actually I have no idea what is the real goal (by OP).
X itself is a client-server app pair, and also there are GUI apps which will run and use that X server (not to speak about the daemons/services used by X). And at this moment I don't know which are supposed to run inside the docker and which parts should run "elsewhere".

By default/design docker is a "closed" container which means it is used to run something inside in a separated environment. Running X that way goes against this concept.

simosx · 05-04-2017, 10:20 AM

docker is an application container, while LXD is a machine container.

It is more natural to do these in LXD.

tty0 · 05-18-2017, 12:21 PM

It's possible to ran gui apps like chromium, libreoffice and a xorg server or desktop in separated containers. You need to share a DISPLAY env variable and some sockets (xorg) to get it running.
There is also a playonlinux image available to play games with wine.

It's possible to run a desktop from simple docker optimized and minimal os (minimal console with docker installed) like RancherOS or Linuxkit.

Because it's my first post I can't post links, so just seach for "github jessfraz dockerfiles" and "joriss playonlinux" for examples.

It's possible to run dbus, but you have to share the dbus policy files from applications with the dbus daemon container. But most applications running without dbus daemon