$ echo "bootlogd install" | sudo dpkg --set-selections
$ echo "initscripts install" | sudo dpkg --set-selections
$ echo "sysvinit install" | sudo dpkg --set-selections
$ echo "sysvinit-utils install" | sudo dpkg --set-selections
$ echo "sysv-rc install" | sudo dpkg --set-selections
$ sudo apt-get install -t unstable systemd libpam-systemd libsystemd-daemon0 libsystemd-login0 bootlogd initscripts sysv-rc sysvinit sysvinit-utils

Only remark after upgrade as for the last time a normal reboot isn’t possible since the system already looks at the new location, but a `halt -f` solves that.

As VirtualBox is mainly a desktop solution, then the other options are Xen and KVM for now. I picked KVM as it is shipped with RHEL6 and part of the vanilla Linux kernel since 2007. Also there is a nice (remote) management solution and closer integration in GNOME 3.4 in the form of GNOME Boxes. So the time has come to give it a go and first we create a line in /etc/fstab to mount the BtrFS subvolume.

LABEL=datavol	/var/lib/libvirt	btrfs	defaults,relatime,nodiratime,subvol=libvirt	0	0

Now we create the BtrFS subvolume and mount it. Afterward we install all required software and make a user member of the right group. It is important to note that one needs to logout and login afterwards. These right are only needed when doing local maintenance.

$ sudo btrfs subvolume create libvirt /media/btrfs-datavol
$ sudo mount /var/lib/libvirt
$ sudo apt-get install qemu-kvm virt-manager virt-viewer virtinst
$ sudo usermod -a -G libvirt <username>
</username>

The machine is now able to run virtual machines if it has an CPU with Intel-VT or AMD-V technology. And the first tests with Debian 6.0, Solaris 11 and Windows 7 looked very promising. The management interface is very clean and people who have worked with Solaris Container the commandline tool virsh is also a good option. One thing that seems to be missing is a storage snapshot option as in VirtualBox, but if it is a real miss I doubt as most images are on BtrFS and BtrFS supports snapshots on subvolume level.

For now KVM appears to be a good and free alternative for VirtualBox and VMWare. It may need some more love in the future, but for now it deserves some more testing from my side together with SELinux for stronger separation of virtual machines. Maybe I can say goodbye to DKMS for recompiling VirtualBox modules with every release and the Qt-toolkit as dependency for VirtualBox and switching back on the default GTK toolkit on my machine.

$ sudo apt-get remove --purge libgcj12 libgcj-common gcj-4.6-jre-headless \
    libgcj12-awt default-jre-headless

This action also made me wonder about the state of LibreOffice as it is mainly a big blob of code on the system like Firefox is as well btw. I read on there website somewhere that making Java an option is a long term goal, but will it be enough? For now it should be, as I prefer my documents in OpenDocument-format. When the next GTK3 based version of Abiword and Gnumeric are released I need to do some testing again to see if they support OpenDocument now better.

$ cd `xdg-user-dir DOWNLOAD`
$ wget http://snapshot.debian.org/archive/debian/20111223T034013Z/pool/main/s/sysvinit/bootlogd_2.88dsf-18_amd64.deb
$ wget http://snapshot.debian.org/archive/debian/20111223T034013Z/pool/main/s/sysvinit/initscripts_2.88dsf-18_amd64.deb
$ wget http://snapshot.debian.org/archive/debian/20111223T034013Z/pool/main/s/sysvinit/sysv-rc_2.88dsf-18_all.deb
$ wget http://snapshot.debian.org/archive/debian/20111223T034013Z/pool/main/s/sysvinit/sysvinit-utils_2.88dsf-18_amd64.deb
$ wget http://snapshot.debian.org/archive/debian/20111223T034013Z/pool/main/s/sysvinit/sysvinit_2.88dsf-18_amd64.deb
$ dpkg -i bootlogd_2.88dsf-18_amd64.deb initscripts_2.88dsf-18_amd64.deb sysvinit_2.88dsf-18_amd64.deb sysvinit-utils_2.88dsf-18_amd64.deb sysv-rc_2.88dsf-18_all.deb

And as there is no solution for now except a dependency change for systemd the package are being placed on hold like the last time they broke systemd.

$ echo "bootlogd hold" | sudo dpkg --set-selections
$ echo "initscripts hold" | sudo dpkg --set-selections
$ echo "sysvinit hold" | sudo dpkg --set-selections
$ echo "sysvinit-utils hold" | sudo dpkg --set-selections
$ echo "sysv-rc hold" | sudo dpkg --set-selections

It sounds strange for Linux-people, but I really wished I had an alternative boot environment like Solaris has. Maybe this is the reason for me to invest more time in read-write within BtrFS.

In the case of thepiratebay.org it looks like it has been done by manipulating DNS-answers. The first attempt is just using the DNS-resolver from the internet access provider and the second is an attempt using Google public resolvers.

$ dig thepiratebay.org
 
; < <>> DiG 9.8.1 < <>> thepiratebay.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER< <- opcode: QUERY, status: NOERROR, id: 6811
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
 
;; QUESTION SECTION:
;thepiratebay.org.		IN	A
 
;; ANSWER SECTION:
thepiratebay.org.	10	IN	A	194.109.6.92
 
;; ADDITIONAL SECTION:
thepiratebay.org.	10	IN	TXT	"Forged by XS4ALL for Stichting B.R.E.I.N."
 
;; Query time: 19 msec
;; SERVER: 192.168.178.1#53(192.168.178.1)
;; WHEN: Sat Feb  4 08:15:35 2012
;; MSG SIZE  rcvd: 104
 
$ dig thepiratebay.org @8.8.8.8
 
; <<>> DiG 9.8.1 < <>> thepiratebay.org @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER< <- opcode: QUERY, status: NOERROR, id: 4847
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
 
;; QUESTION SECTION:
;thepiratebay.org.		IN	A
 
;; ANSWER SECTION:
thepiratebay.org.	2596	IN	A	194.71.107.50
 
;; Query time: 26 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sat Feb  4 08:16:16 2012
;; MSG SIZE  rcvd: 50

By just changing DNS resolvers on the client or internet router the censorship can be bypassed for now. The question remaining is how long this is going to stand when the first article is published by a big computer magazine on how to bypass it. Or when sites also get an .onion to bypass DNS completely. ]]> http://blog.dailystuff.nl/2012/02/blocking-the-piratebay/feed/ 0 http://blog.dailystuff.nl/2012/02/censorship-in-chinawthe-netherlands/ http://blog.dailystuff.nl/2012/02/censorship-in-chinawthe-netherlands/#comments Tue, 31 Jan 2012 23:11:59 +0000 Hans http://blog.dailystuff.nl/?p=1135 Continue reading →]]> A picture says more than a thousand words, but censorship in The Netherlands has started thanks to Stichting Brein.

As from now all my DVD’s are for sale on Bol.com and yes in March I’ll join the month of not spending a penny on the entertainment industry which was proposed for SOPA and PIPA. It only make me wonder how ACTA is going to influence the Internet when it gets approved.

With Firefox 10 WebGL works and there for also Google Street View works without the need of Flash. Yes, another dependency on Flash has been removed. The previous major dependency was YouTube, but as some may have noticed they also are in a transition from Flash to HTML5 video where you get the HTML5 variant when Flash doesn’t work.

As more and more websites switch from a Flash-player for video toward HTML5 in under a year it makes you wonder what WebGL is going to change. Was HTML5 a year ago only for the geeks and cutting edge, now more and more starts to depend on it. With HTML5 Canvas a lot of Arcade games where rewritten to run in a webbrowser. With WebGL the question comes when Doom has been rewritten to run in a webbrowser. Maybe something for a Google Summer of Code project?

LABEL=datavol	/home	btrfs	defaults,subvol=home	0	0
LABEL=datavol	/media/btrfs-datavol	btrfs	defaults,noauto,subvolid=0	0	0

As /media is a temporary file system, meaning it is being recreated with every reboot, we need to create a mountpoint for the BtrFS volume before mounting. After that we create two read-only snapshots with a small delay in between. As there is currently no naming guide for how to call snapshots, I adopted the ZFS naming schema with the @-sign as separator between the subvolume name and timestamp.

$ sudo mkdir -m 0755 /media/btrfs-datavol
$ sudo mount /media/btrfs-datavol
$ cd /media/btrfs-datavol
$ sudo btrfs subvolume snapshot -r home home\@`date "+%Y%M%d-%H%m%S-%Z"`
Create a readonly snapshot of 'home' in './home@20124721-080109-CET
...
$ sudo btrfs subvolume snapshot -r home home\@`date "+%Y%M%d-%H%m%S-%Z"`
Create a readonly snapshot of 'home' in './home@20124721-080131-CET'
$ ls -l
totaal 0
drwxr-xr-x 1 root root 52 nov 21  2010 home
drwxr-xr-x 1 root root 52 nov 21  2010 home@20124721-080109-CET
drwxr-xr-x 1 root root 52 nov 21  2010 home@20124721-080131-CET

We now have two read-only snapshots and lets test to see if they are real read-only subvolumes. The creation a new file shouldn’t be possible.

$sudo touch home@20124721-080109-CET/test.txt
touch: cannot touch `home@20124721-080109-CET/test.txt': Read-only file system

Creating snapshots is fun and handy for migrations or as on disk backup solution, but they do consume space as the delta’s between snapshots is being kept on disk. Meaning that changes between the snapshots are being keept on disk even when you remove them. Freeing diskspace will not only be removing them from the current snapshot, but also removing previous snapshots that include the removed data.

$ sudo btrfs subvolume delete home@20124721-080109-CET
Delete subvolume '/media/btrfs-datavol/home@20124721-080109-CET'
$ ls -l 
totaal 0
drwxr-xr-x 1 root root 52 nov 21  2010 home
drwxr-xr-x 1 root root 52 nov 21  2010 home@20124721-080131-CET

As last step we unmount the BtrFS volume again. This is where ZFS and BtrFS differ too much for my taste. To create and access snapshots on ZFS the zpool doesn’t needs to be mounted, but then again with the first few release of ZFS the zpool needed to mounted as well. So there is still hope as BtrFS is still under development.

$ sudo umount /media/btrfs-datavol

Seeing what is possible with BtrFS, Sun’s TimeSlider becomes an option. Also the option of Live Upgrades with rollbacks as is possible with Solaris 11, but for that BtrFS with read-write snapshots needs to be tested in the near future.