[GIS.lab] chroot

[Matej Pastor]

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Dňa Wed, 20 Apr 2016 15:32:12 +0200
Ludmila Furtkevicova <ludmilafurtkevicov at gmail.com> napísal/a:

> Hi,
> 
> Is there any difference when I say `client's root` or `chroot`? I suppose
> that `client's chroot`
> is not the best expression - many times used in GIS.lab wiki.
> Or am I wrong?
> What should I use to be correct in GIS.lab materials? E.g. when talking
> about image and client's root backup ..
> 
> Thanks ..
> 
> Ludmila

"client's root" is concrete directory (on gis.lab server) in which gis.lab client
is installed (with a special tool named 'debootstrap'). it has almost same filesystem
hierarchy as a standard xubuntu desktop installation with our gis.lab integration
changes (and this is what you see in running gis.lab client). from this directory
is then created gis.lab client image. this image is mounted (over network)
as a "client's root partition" during boot process. 

chroot (from wikipedia :)):

"A chroot on Unix operating systems is an operation that changes the apparent root directory
for the current running process and its children. A program that is run in such a modified environment
cannot name (and therefore normally cannot access) files outside the designated directory tree."

if you want to e.g. install new package in client, you must do it in "client's chroot".
'chroot' is a tool which enable it:

    chroot /path/to/client/root/directory apt-get install firefox

this command install firefox to client's root within chroot :)

very simple comparision: 'root' is a directory and 'chroot' is an operation.

- -- 
Matej Pastor
email: matej.pastor at initipi.sk
gpg: http://www.initipi.sk/gpg/matej.pastor_initipi.sk.gpg
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