Simpler method for fat/thin client setups

[David Groos]

Personally, while I've grown to enjoy the command line, I would suffer little sense of loss at no longer needing to use it in chroot development and maintenance.  I like the idea that, as you set up and develop the capabilities of the server one is simultaneously accomplishing the same with the thin/fat client--very efficient and transparent.  

The need to reboot the server into grub recovery mode is a limitation for my implementation.  I manage the edubuntu servers remotely and in one case it is not physically accessible.  Therefore I use terminal with ssh but even more use OpenNX to access the server.  Sounds like everything would work great here except I don't see how I could do the grub screen step since this screen is not available to OpenNX--though is it via ssh?  Do you see a work-around?  Sounds like BTRFS snapshots will solve this but not sure of its timeline.  Although with the lower server needs with the fatclient technology, I may be moving to having each classroom use a good desktop (the teachers) as the server and no longer use a full-blown server in a tech closet.  Nice to have options.

At the end of the summer/before the start of the school year I set up one 'golden server' then using clonezilla, clone that image to the other servers only needing to adjust a few network config files.  How would this new system impact how I have been propagating the server?

It seems you are saying that I could get LDAP authentication, Apache caching/filtering working on the server and then not have them running on the clients--is this like the opposite of localapps?  Would I have to specify each application I don't want to run locally?  I may need some guidance here.

Let me know how I can support the internationalization or testing of this: it is continuing to move Ubuntu/LTSP in a highly practical direction.  This will help me in my push to get Ubuntu/Edubuntu more into the mainstream of our school district--whenever you lower the entrance bar for a technology you make it a more welcoming, more accessible option.  Thanks for your continued efforts, Alkis.

Looking forward to seeing others' responses.

David G
 
On Apr 2, 2012, at 12:58 AM, Alkis Georgopoulos wrote:

> Now that the ltsp-server and ltsp-client packages are allowed to be installed simultaneously (LP: #950945), I thought of an extremely simple method to install and maintain LTSP fat/thin computer labs that should be appealing to certain setups like small school labs.
> We'll probably start using it in Greek schools in a month, and I'd like to ask the community for feedback on where this could lead to problems, and also on whether there's interest in an internationalized version of the "ltsp-server-pnp" package that we'll develop to automate this.
> 
> The installation steps for this new method will be:
> 1. Install your server normally with any DE you prefer (Gnome, KDE, XFCE, LXDE...). Also install and configure on the server any applications that you want to have in your thin/fat clients.
> 2. Add the repository for the yet-to-be-developed ltsp-server-pnp package, which automatically installs and configures ltsp-server, ltsp-client, dnsmasq, PXE menus etc for you.
> 3. Reboot your server and select "Recovery console" in the grub menu. From the recovery menu that will appear, select "Generate LTSP image". This will create the /opt/ltsp/images/i386.img NBD image, and it will need about 5-10 minutes to complete, without requiring Internet connectivity.
> 
> That's all, you can then boot your server normally and start your thin/fat clients. If you need to "update your chroot" in the future, you just do any changes you want directly on the server (add/remove apps or settings) and follow step (3) again.
> 
> Pros:
>  * Great simplicity. As you've seen, there's *no LTSP chroot involved*, so no "ltsp-build-client" step, no "ltsp-chroot install packages" step, no "manually transfer gconf mandatory settings to the chroot" step.
> 
> Cons:
>  * Loss of flexibility. The server needs to be the same arch as the clients, so you'll probably want the i386-pae kernel in your server. You can't even have different packages installed in your server than in your thin/fat clients. But you can still have e.g. apache, mysql, sshd etc installed on your server and put them in the RM_SYSTEM_SERVICES lts.conf directive so that they don't run in your clients. No, that doesn't put any additional RAM overhead, your clients can still have as low as 128 MB RAM no matter how many services you have installed on your server. And of course in bigger setups you can use a separate server for NFS/apache/whatever, and only keep the LTSP-related services in the server where ltsp-server-pnp runs.
>  * Security concerns. E.g. the clients will have the same sshd keys as your server. But I think that in step (3) above, the security-sensitive data can be regenerated or omitted. And of course /home, /srv, /opt, and user's entries in /etc/passwd and /etc/shadow will be omitted too in the NBD image.
>  * Finally, your server needs to be rebooted to update the NBD image, so some downtime is involved. This will be avoided in the future when BTRFS snapshots will be available.
> 
> Thoughts? And, does anyone care about an internationalized Ubuntu Precise/Debian Wheezy package for this?
> 
> -- 
> edubuntu-users mailing list
> edubuntu-users at lists.ubuntu.com
> Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/edubuntu-users