Cockpit as a privileged container?

Daniel J Walsh dwalsh at redhat.com
Tue Aug 12 13:51:35 UTC 2014


On 08/10/2014 05:02 AM, Stef Walter wrote:
> On 09.08.2014 01:04, Colin Walters wrote:
>> On Fri, Aug 8, 2014, at 11:57 AM, Stef Walter wrote:
>>> So to summarize this... Do you know of anyone who's tried this stuff out
>>> with Cockpit? Interested in the results in any case, and open to patches
>>> that help make it work.
>> I don't offhand.  One way to approach this might be to mount the host
>> file system at /sysroot or something in the container.  The cockpit
>> would have to conditionalize itself and say: Am I in a container? 
> Is there a standard way to do this on Linux?
We are working to add an environment variable that says container=docker
in all Fedora/RHEL images.  We are hoping to
get this ability upstream soon.  If your question was about /sysroot for
the host, I guess the closest thing to a standard is anaconda and
libguesfs.  But those two do not agree.   I think someone in your group
suggested /host.
>
>> Look
>> at /sysroot/proc.
> So I guess you're mostly talking about cockpit-agent here, although
> cockpit-ws would also need to some how trick PAM into looking at the
> /sysroot/etc/pam.d path ... But I guess that could be via a symlink.
>
> I guess that also when we connect to such a system via ssh, we would
> have to run the cockpit-agent command at a different path? What would
> that path be?
>
>> Though that might get untenable for things like systemd APIs that are
>> basically just wrappers around looking at files in /run.  
> We would probably have to symlink /run to /sysroot/run
>
> In fact the only interesting parts of the cockpit container file system
> would be /usr/libexec/cockpit-* and /usr/share/cockpit.
Well stuff in /usr/lib64 is also probably used and any parts of
coreutils you take use.  Potentially some configuration
you might want shipped within a container.
>> Maybe flip it around and try to have cockpit-in-container have its data
>> all isolated in /usr/lib/cockpit (including the binaries).
>>
>> On the other hand - if we made Cockpit work in this pattern, I'd say it
>> would work for any management agent / config system / etc.
> Right. So how does this work in real life (for example with Docker). Is
> there a way to just remount / with a bind mount into the container at /
> and then remount the container file system in an alternate place?
>
> Stef
You could mount / at / theoretically, but I believe as soon as you did
this your app would loose its shared libraries and could start acting
strange.
> _______________________________________________
> cockpit-devel mailing list
> cockpit-devel at lists.fedorahosted.org
> https://lists.fedorahosted.org/mailman/listinfo/cockpit-devel



More information about the cockpit-devel mailing list