My role as a Core Engineer in the Storage Platform Group involves architecting and engineering storage software components in the Linux kernel. Hopefully some of these components will be released soon, along with our product [...]]]> Since last month (Feb. 2012), I’ve started working for OnApp, a UK-based company developing cloud software for hosts.

My role as a Core Engineer in the Storage Platform Group involves architecting and engineering storage software components in the Linux kernel. Hopefully some of these components will be released soon, along with our product releases. For the moment stay tuned for more news & releases soon…

#> 'C:\Program Files\Oracle\VirtualBox\VBoxManage.exe' clonehd .\MyVM.vdi .\NewVM.vdi

VBoxManage.exe: error: Cannot register the hard disk 'C:\VMs\MyVM.vdi' {601b44ed-a301-45a7-8b17-9b2185040a1e} [...]]]> A VM disk image in Virtual Box (version 4.0.6) can be cloned using the command line “VBoxManage” tool with the “clonehd” command. Unfortunately, cloning a VM that already has a registered UUID in Virtual Box fails like that:


#> 'C:\Program Files\Oracle\VirtualBox\VBoxManage.exe' clonehd .\MyVM.vdi .\NewVM.vdi

VBoxManage.exe: error: Cannot register the hard disk 'C:\VMs\MyVM.vdi' {601b44ed-a301-45a7-8b17-9b2185040a1e} because a hard disk 'C:\VMs\MyVM1.vdi' with UUID {601b44ed-a301-45a7-8b17-9b2185040a1e} already exists
VBoxManage.exe: error: Details: code E_INVALIDARG (0x80070057), component VirtualBox, interface IVirtualBox, callee IUnknown Context: "OpenMedium(Bstr(pszFilenameOrUuid).raw(), enmDevType, AccessMode_ReadWrite, pMedium.asOutParam())" at line 209
of file VBoxManageDisk.cpp

A quick way to clone the disk would just be to copy the file, don’t you think? Unfortunately the UUID still remains embedded in the copied VM image and does not allow you to load the new VM in the same machine!

One solution would be to copy the disk image and then change the UUID of the copied image to a new one. Such an option, however, does not show up on the VBoxManage printout!

Fortunately there’s an undocumented command of VBoxManage to do what we need, as I found in https://forums.virtualbox.org/viewtopic.php?p=33678

Unfortunately the command shown there was wrong, or it may have changed in recent versions of Virtual Box:

#> 'C:\Program Files\Oracle\VirtualBox\VBoxManage.exe' internalcommands setvdiuuid .\MyVM.vdi
Syntax error: Invalid command 'setvdiuuid'

The correct command is ‘sethduuid’ (showing up on the internalcommands usage printout) and using that we can finally change the UUID and use the copied VM image as a new VM:


#> 'C:\Program Files\Oracle\VirtualBox\VBoxManage.exe' internalcommands sethduuid .\MyVM.vdi
UUID changed to: 0156199f-6e83-4cd6-97b7-c9e24d9cd26d

All done!
You can now create a new VM on the same computer using the copied disk image without any problems.

A quick hack-style solution is to go to TortoiseSVN->Settings->Network and [...]]]> Configuring recent versions of toirtoise SVN to work with non-standard ports is a bit tricky. I tried editing the “subversion config file” through Settings->General->Edit, to using an ssh command line, like the one I’m using on Linux for the same repository, but that didn’t work.

A quick hack-style solution is to go to TortoiseSVN->Settings->Network and set the SSH client to (assuming port number XX):
“C:\Program Files\TortoiseSVN\bin\TortoisePlink.exe -P XX”
(The hack is also described here: http://www.supernifty.com.au/blog/2007/09/27/hack-it-1-change-the-tortoisesvn-ssh-port/ )

The issue with this hack is that if you have multiple repositories, each with different ports, this does not work. A more generic and elegant solultion is to use a batch script that is able to parse correctly an SVN URL of the type svn+ssh://user@host.com:port/svn/dir with the correct port, and use it as a wrapper of your TortoiseSVN ssh agent.

You can find a working script with this solution here: http://unformatt.com/news/non-standard-ssh-ports-with-tortoise-svn/

I’m quoting the batch script here (for redundancy purposes):

@echo off
set HOST=%1
set PORT=%HOST:*:=%

IF [%PORT%]==[%HOST%] (
 set PORT=22
 )
 c:\\Progra~1\\TortoiseSVN\\bin\\TortoisePlink.exe -P %PORT% %HOST% %2 %3

So, lots [...]]]> For the last few weeks I’ve been working on a new project, building an electronic store that will hopefully grow into a successful business. Unfortunately I’ve had to put all my other projects on hold for this, but hopefully this won’t take more than a couple of months …I know, famous last words.

So, lots of new things for me to learn… I’ve been exploring the area of e-commerce platforms and played with a few that seemed promising. Unfortunately there’s a lot of old stuff out there, dating from 10 years ago. There are some promising new platforms also, but many of them lack the more advanced features I need, or were just too expensive or too complicated to build on.

I have finally decided to go with Magento, an open-source e-commerce platform built with PHP. In case you are curious to know which were the ‘finalists’ in my quest for an e-commerce platform, my shortlist included also Shopify and Prestashop.

Now, let’s see where this rabbit hole will take me…

I’ve had this issue for some time, because I had tuned Vim for writing in C/C++, which of course proves quite annoying when trying to write Python code (no braces darling!).

Googling the issue I came up with [...]]]> Today I solved the problem of properly indenting my Python code with my favorite editor (Vim 7.2).

I’ve had this issue for some time, because I had tuned Vim for writing in C/C++, which of course proves quite annoying when trying to write Python code (no braces darling!).

Googling the issue I came up with the article “Indenting Python with VIM” which proves quite useful, but unfortunately did not work out of the box for me.

The issue was that the “ftplugin” solution suggested in the article was not enabled on my Vim. After some searching I found out that I should enter the following commands in my .gvimrc:

“enable filetype plugin and indentation
filetype plugin on
filetype indent on

After that the settings in ~/.vim/ftplugin/python.vim and ~/.vim/indent/python.vim (downloaded from http://www.vim.org/scripts/script.php?script_id=974) script files worked as described.

Problem solved. Now let’s write some code!

This post has been mirrored on my posterous blog Gnosis

A [...]]]>

I needed to “compile” a latex document using the tkiz package. After spending quite a few time trying to set this up on CentOS and Fedora, I finally gave up. Fortunately Ubuntu had a working pre-built package that includes pfg and tkiz, but this also required two online searches to deal with latex errors.

A summary of the process for RHEL/CentOS/Fedora 

I searched many times for RPMs with tkiz/pgf for RHEL 5 or FC12 (to install it on our CentOS server). No luck on Google, Rpmfind or the pgf project site. So I decided to manually install it, following the documentation in http://media.texample.net/pgf/builds/pgfmanualCVS2010-06-02.pdf .

I downloaded the sources from http://www.texample.net/tikz/ , installed them in the /usr/share/texmf of the CentOS system and run “texhash” and “mktexlsr” (should do the same thing, but I tried both). The result was that latex was still missing the tkiz.sty package when I tried it,
although it still existed under /usr/share/texmf/…
I tried to manually provide the filename. It worked, but then it asked for the following (in order): pgffor.sty, pgfrcs.sty, pgfutil-common.tex. After the fourth file I gave up on installing the package on CentOS and decided to try the pre-built Ubuntu package.

The Ubuntu 10 process

I fired up a VM with Ubuntu 10 on Virtual Box, which however did not have any latex/tetex installed on it. Everything went smoothly after the command:

sudo apt-get install pgf 

After 350MB of packages installed on my disk I tried to run latex on my document, with the following result:
——————————————————–
Error:
kpathsea: Running mktexmf ptmr7t
! I can’t find file `ptmr7t’.
<*> …:=ljfour; mag:=1; nonstopmode; input ptmr7t

Please type another input file name
! Emergency stop.
<*> …:=ljfour; mag:=1; nonstopmode; input ptmr7t

Transcript written on mfput.log.
grep: ptmr7t.log: No such file or directory
mktextfm: `mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input ptmr7t’ failed to make ptmr7t.tfm.
kpathsea: Appending font creation commands to missfont.log.”
——————————————————–

A google search produced this helpful document: http://sysad.wordpress.com/2008/11/06/ubuntu-hardy-to-intrepid-upgrade-remnants/

After a “sudo apt-get install texlive-fonts-recommended“, I was missing algorithm.sty:

“! LaTeX Error: File `algorithm.sty’ not found.”

Another google search produced: http://ubuntuforums.org/archive/index.php/t-800376.html

“Most of these things are in the repositories. I think algorithm.sty is contained in the texlive-science package. So you just have to do:

sudo apt-get install texlive-science”

Finally, it all went fine. My latex file was so happilly processed, I could not even scream about the time lost in this

[This post is mirrored on my Gnosis posterous blog ]