Greetings, people of the Internet! Welcome to the personal website of Jonathan Carter!
// November 27th, 2010 // No Comments » // Jonathan
Living in Cape Town for pretty much all my life, I saw snow for the first time a few weeks ago while traveling back to Canada from the US. People here in Sherbrooke told me it wasn’t real snow because it melted as soon as it hit the ground. A few minutes ago, my car was on a black tarred driveway, now you just see snow:
Outside from my home office:
Next month when it heaps up nicely I’ll build a snowman in the front and post some pics :)
// November 24th, 2010 // 30 Comments » // Education, Free Software
Thin clients are a great way to lower initial deployment as well as running costs in classrooms, libraries and similar organisations, but they have some limitations, especially when it comes to graphical and CPU intensive software. Even playing a video on one or more thin clients can often be enough to drag the network performance to crawling speeds. In recent LTSP versions, it became possible to run some applications locally, making it possible to use the local CPU/GPU/memory and drastically improve performance all-round. Since LTSP 5.2.1 (that ships with Ubuntu 10.04), it’s been possible to also run everything locally. This essentially makes a terminal a complete fat client that simply uses the network as a storage device. It combines many of the benefits of thin clients and fat clients, while also requiring a less powerful server since it basically becomes just a file server.
Install it from the command line using apt-get install ltsp-server-standalone or by installing it from the Ubuntu Software Centre. If you’d like to configure a DHCP server seperately, then you should use the ltsp-server package instead.
LTSP will work out of the box if you have an interface configured on the 192.168.0.0/24 range. If you would like to use another IP range, you will have to edit /etc/ltsp/dhcpd.conf and adjust it to your needs. Usually LTSP is run from a separate network interface that connects to the rest of the network. If it’s not yet configured, you can add the configuration for a second interface to the /etc/network/interfaces file. Example:
auto eth1iface eth1 inet staticaddress 192.168.0.254netmask 255.255.255.0
An LTSP fat client image can be used for both thin clients and fat clients alike. This is useful if you have a mixture of newer, more powerful machines as well as very old machines that can be used as thin clients only.
ltsp-build-client --fat-client --fat-client-desktop edubuntu-desktop --arch i386 --skipimage
Edubuntu-desktop can also be replaced with kubuntu-desktop, ubuntu-desktop or xubuntu-desktop. The Edubuntu one is probably most tested though. It’s recommended that you use the i386 architecture for the thin client environment (you can do this even if your server is amd64), the reason for this is that many machines (such as Intel Atom based thin clients) are not 64bit capable. The skipimage switch will prevent the image from being built now, since we want to install other software on it first. You can get all ltsp-build-client options by entering “ltsp-build-client –extra-help”.
chroot /opt/ltsp/i386 apt-get install htop openarena stellarium vlc
The example above will change-root to the ltsp environment and install htop, openarena, stellarium and vlc. These are just examples, you can choose any other software that you intend to run on your LTSP fat client. Next, sync the ssh keys (used for logins) and update the LTSP image:
ltsp-update-sshkeysltsp-update-image
Restart networking:
/etc/init.d/networking restart
Restart the DHCP server:
/etc/init.d/dhcp3-server restart
That’s it, your LTSP Fat client server is now installed and ready for use. All you need to do now is connect one or more machines to the configured network and set them to boot from PXE or Etherboot.
The diskless workstation will use the LTSP image in a similar way as a local hard disk and will only read the information over the network as required. It doesn’t download the whole image at boot time, so it doesn’t slow down the boot process by installing more software and it doesn’t use any additional RAM either.
Create a file called /var/lib/tftpboot/ltsp/i386/lts.conf if it doesn’t exist already. lts.conf is the configuration file for LTSP. The [default] section contains settings that apply to all machines on the network. You can specify exceptions to this by specifying the mac address between brackets:
[default] LDM_DIRECTX=true [00:A1:08:EB:43:27] LTSP_FATCLIENT=false
LDM_DIREXTX disables SSH encryption of thin client sessions. It is insecure, but boosts performance and might be required for very old machines or of you have limited CPU power on the server. The machine with the MAC address 00:A1:08:EB:43:27 will function as a thin client instead of a fat client. For more settings available in lts.conf, refer to the manual page.
DRBL is an alternative to LTSP that does diskless fat clients only. LTSP already matches all the functionality of DRBL, and on top of that supports multiple architectures, mixed thin/fat environments, individual client configuration as well as being properly packaged in Debian and Ubuntu already. Spending more valuable resources on supporting DRBL in Edubuntu wouldn’t bring any benefit to any of our users, although if someone wants it really badly, we’ll be happy to review any packages that they submit through the usual process.
The cool kids these days walk around with dual-core ARM based devices with 2GB of RAM in their pockets. With computing becoming so ubiquitous, does it make sense for schools and other organisations to still make use of LTSP? I’m quite sure that the way we use computers over the next few years is going to change drastically, but for now LTSP still offers a great way to cut down on administration and maintenance costs with very little compromise.
LTSP uses the X Window System to display applications that run on a remote application server. The X Window System is planned to be replaced by Wayland in the near future. Wayland offers better and simpler means to write new software on top of it, which will allow developers to write great software faster and with less trouble than before. In order to achieve this simplicity, Wayland had to drop the network transparency features that is present in the X Window System. This will certainly bring on some required changes on how LTSP is implemented, but at least there are already some options available that the LTSP team will investigate, and there’s no reason why Wayland should mean an end to LTSP.
// November 8th, 2010 // No Comments » // Free Software
Ubuntu Weekly Newsletter #217 is now available!
Covers the period from 17 October to 7 November 2010:
We’ve run in to some delays getting this issue out due to the Ubuntu Developer Summit held in Orlando, Florida two weeks ago, on top of that our editors home literally burnt down so we had to scramble a bit to make this issue happen! Enjoy!
// November 8th, 2010 // 1 Comment » // Free Software, Jonathan, Project Mayhem
I’ve taken a lot of time recently to think about my future and what I want to do with my life. Part of the process in refocusing and doing what I really want to do is cutting back on distractions and some things that just take up too much time.
I unsubscribed from a bunch of mailing lists (down from hundreds to dozens), quit from a lot of IRC channels (down from more than 50 to 16) and unsubscribed from a big bunch of blueprints, bug reports and other stuff that sends out email in Launchpad.net. The reason for all of this isn’t because I’ve lost interest in those things I unsubscribed from, but more a case of getting back to basics. So if anyone is wondering, it’s certainly not because I got angry or bored or anything like that, I just really needed to cut down!
At my French classes on Mondays we usually spend some time speaking about what we did the last weekend. I usually get stuck there and can’t think of much that I did besides work. I’ve spent entire weekends before just thinking or worrying about stuff that I need to do. I’m going to change that. I put together a *really* big mindmap in freemind mapping out some ideas that I’ve had that spans career choices, hobbies, stuff just for fun, financial targets, training and education and more. It’s big and I’ll probably not be able to do everything on there in my lifetime (which is actually fucking scary), but I certainly want to make the most of it and prioritize my time better. I’m going to have to learn to rely on other people much more in the future and learn to let go a bit more, which is hard, but I think doable!
Specifics will follow in more blog entries… or if things go well you’ll read about it on digg/slashdot/etc ;)
