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Getting started - not basic enough

I went to https://docs.docker.com/engine/docker-overview/ and started reading about docker. I got as far as ’ Example docker run command’ and decided to try it. I noticed docker was already installed on my PC (openSUSE Leap 15.0 BTW) though I don’t remember how it got there. So I typed:

$ docker run -i -t ubuntu /bin/bash
docker: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?.
See 'docker run --help'.

So I typed docker run --help and got a whole list of options but nothing that tells me how to start the docker daemon, assuming that is what I need to do.

So either the web page is wrong in starting with that example command before starting a daemon, or the command’s error message is wrong in what it told me to do, or both.

So what do I do?

Hi :slight_smile:

Note that docker might allready be running, but you’re not allowed to run the command, you can try and run the command with “sudo” to see if that helps.

Else you can try and start the service, like any other: systemctl start docker

There is no docker-ce support for SUSE (see: https://docs.docker.com/install/#supported-platforms)
I am quite sure if you type ‘sudo docker info’, the version number will be 1.13.

If so, this is a docker redistribution of the os vendor and as such supported by the vendor.

Update: seems like suse redistibutes newer versions as well https://software.opensuse.org/package/docker. Though, you will not find any docker-ce downloads for suse on the official docker pages. Just for docker-ee, which requires a subscription.

Thanks, that starts the daemon. I suppose that really I should enable it as well. Where do I bug report that overview web page?

Well, you’re right that I need more privilege but docker tells me explicitly, so there’s no danger of confusion:

$ docker run -i -t ubuntu /bin/bash
docker: Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Post http://%2Fvar%2Frun%2Fdocker.sock/v1.39/containers/create: dial unix /var/run/docker.sock: connect: permission denied.
See 'docker run --help'.

What privilege does it actually need? I’m loath to run some software I’ve never come across before as root. I see that dockerd itself is running as root and the socket is owned by root but has rw permission for the docker group. So is it enough to make myself a member of the docker group perhaps?

(I’m generally prepared to trust what comes out of an official openSUSE repository, but asking me to trust an arbitrary image from the docker hub with root privileges is a step too far for me. Is the security model descibed somewhere?)

Thanks for your help.

Hi again.

Yes either sudo or be a member of group “docker”

I thought the point of docker was to allow running things anywhere? Specifically what I’m looking to do is run an application on a RPi image on my openSUSE box. And I thought open communities were about providing help to people in various out of the box situations. Is discussing an implementation on openSUSE off-topic here?

You’re faith is misplaced then. It says Server Version: 18.09.1.

Well, if I find any problems with the distribution, I will bug report it to the distribution. At the moment, the difficulties I’m having appear to be with the public documentation.

BTW, the notification I received from the forum indicates that you posted a completely different message then deleted it all and replaced it with what is visible. Why did you do that? It would be bad manners in the other communities I’m part of, and indeed is impossible on my preferred medium of mailing lists.

I was simply not statisfied with my initial response. So you would’ve prefered a chain of comments, rather then a correction?

My first impression was: the manual points out the missing steps of the installation - the getting started guide even mentions them as prerequirement. Along the installation guide the missing information could be found. Then I remembered that there is generaly no support for Docker CE on SUSE by Docker Inc. Not even Docker EE is available for openSUSE.

Thus said, usualy vendors like SUSE and RHEL patch things up regarding their needs, which makes some situation not reproducable for people running the vanila versions.

The page has the objective to build up theoretical foundations. The command was an illusrtation on how a typical command looks like. Getting started is located at https://docs.docker.com/get-started/.

Yes, you supplied information to me that you have not published to anybody else that was very different to what you eventually said. I would publish it myself but that is bad manners too. The point is that once you’ve published something, it should be made available to all and stay as a matter of record.

I should have pointed out that I got to that page via a google search, so I have not (yet) read any other parts of what I have now come to understand is a sequenced tutorial. So what the other pages say is not useful to answering my problem or that of any other person in the same situation. I have bug-reported the issue and will make a concrete suggestion for wording changes. [edit]: I have done so in issue #8592

But I’m not asking for support from Docker, Inc. I’m enquiring of the community.

I notice your subsequent answer quotes my question but fails to answer it. Fortunately I had found the appropriate link myself. Your answer tries to justify something that doesn’t need justifying, but does need explaining on the page itself, IMHO.

The idea was to point to you to the installtion guide, which is not available for your distro.

If your OS would have been supported, you would have found the instructions required to see how to install docker, get the service up and running and start containers the right way.

Your OS not beeing supported has several consequences, one of them beeing that it is not fully covered in the documentations.