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Xen DomU clock issues

I just setup a Xen DomU (Debian Lenny) and found that when I tried to live migrate it between hosts, any pings would just hang.  I found my logs filled with clock warnings about going backwards in time.  Here is how I resolved this.

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Dual Boot Setup Headache and Warning

December 6, 2008 was an important date in my life. That evening we had a launch party in New York for the start up I'd been working with since September. More significantly, it was my last day with a Windows computer in my home. In reality, I was supposed to be getting doing a dual boot installation so my family could continue to use the Windows software they were accustomed to, and I could play around in Linux world. All on the same computer. It seemed so simple.

The directions were in front of me, printed out from the Internet several days before. I hardly needed them, though, as I had read through them again and again as I struggled to work up the nerve to do the installation. The whole process took less than half and hour, but as I rebooted a problem appeared.

When a standard PC boots up you see BIOS working.  What was supposed to happen was that I would see an option to log into Windows or go ahead and boot into Ubuntu, which was the new default. That option appeared, but no amount of key-tapping would make it change. Time and again I rebooted, only to be sent -- after a brief wait -- into Ubuntu.

Scouring the Internet and trying different tricks got me nowhere. Folks on the Ubuntu forums were very kind and tried to be helpful, but this was a no-go.

My wife managed to pull me away from the computer to get ready for the launch party. We had a very good time, but the computer problem at home gnawed at me.

We got home late, and I stayed up even later. By the time 2:30am rolled around I had accepted the inevitable and we had a full Ubuntu installation on our computer. I was glad I'd backed up our personal folders of documents and pictures.

It took a few days to realize completely what had happened, but now it is crystal clear. Our computer does not have any PS2 ports. Instead, the keyboard and pretty much everything else uses UBS connections. The version of BIOS on this desktop doesn't recognize USB ports, so the keyboard fails to be identified and cannot be used in BIOS. Since the average user would never have any reason to be poking around in BIOS, this normally wouldn't be a problem. Neither Windows XP nor Ubuntu 8.10 have any problem with USB keyboards.

So, if you are thinking about setting up your computer for dual boot Windows/Ubuntu use, take a closer look at your hardware and at BIOS. If you have USB ports only for the keyboard and if you see the magic words "keyboard failure" anywhere as your computer boots up, don't try a dual boot install.

That said, now that I've learned my way around Linux to some extent, I wouldn't want to go back. I've done maintenance on friends' Windows computers since switching to Ubuntu and have been shocked at how shoddy Windows looks in comparison.

Note: This post originally appeared on my blog, Igneous Quill.  Some minor editing to the text was made for this post.


Convert a .svg file to a .png in Ubuntu

Install ImageMagick for converting:

sudo aptitude install imagemagick

Convert the image with antialiasing:

convert +antialias image.svg image.png

 Confirm that the file is indeed a png:

file image.png


Xen: Create a Jaunty DomU using xen-create-image

These are instructions for creating an Ubuntu Jaunty DomU on Debian Lenny Dom0 using Xen 3.2.1 that comes with Lenny.  I'm installing into an LVM rather than using a file image.  See this HowtoForge article for background of my particular setup.  This tutorial assumes you're working from a similar setup with an iscsi target and LVM-based VMs.

 The reason I'm posting this is because I had such a hard time finding some combination of tools that worked correctly to do this.  I tried a few options but had little success:

  • debootstrap - Didn't seem to work with Jaunty at all.  It would just crash
  • vm-install - Doesn't support LVM-based VMs by default, but there is a procedure for converting the qcow image to an LVM
What I found is that I could find no way of creating the LVM-based VM in Lenny.  I actually had to create a sid instance first and then install my open-iscsi and xen-utils into the sid VM, then use SID to populate the VM. 

Perform the following actions in your SID vm or workstation

Note:  You'll need your /etc/xen-tools/xen-tools.conf setup like the instructions in the HowtoForge article (things like gateway, netmask, broadcast, passwd, fs type, install-method, etc).

Whenever I would try to build the vm with the default partitions, it would always fail.  For some reason the resulting vm would have an fstab that shows something like sda1 and sda2 instead of xvda1 and xvda2.  I had to create my own partition scheme before anything would work right.  Here's mine:

$ sudo cat /etc/xen-tools/partitions.d/with-data



 You will need to create a symlink for jaunty so that the option is recognized at the command-line. 

$ cd /usr/lib/xen-tools

$ sudo ln -s edgy.d jaunty.d 

Now, finally, you can create the image.  This step may take some time

$ xen-create-image --hostname=myserver --dhcp --lvm=vg_xen --dist=jaunty --mirror= --size=4Gb --memory=512Mb --swap=512MB --arch=i386 --partitions=with-data

 Since you're building the LVM on a different machine than it will eventually run on, you'll need to  copy the resulting xen config to the correct server:

$ scp /etc/xen/myserver.cfg root@realhost:/etc/xen/

That should be all you need to get this working.


Install NetBackup Client on Ubuntu Jaunty (i386 and amd64)

Many enterprises use the Symantec NetBackup software to backup machines.  Last time I checked (6 months ago?), they didn't support Debian-based distros.  I've been using this process since around Hardy and just recently tested this in a Jaunty Xen VM and it seems to be working (waiting for admin to run a backup on my machine to check)

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My first entry.

My first entry.
This is my first entry. Right now just looking around and stuff. Will post more soon.


The Calculus Integrator

The Calculus Integrator
Also, if you have not been to my open source program that I am creating, The Calculus Integrator, I would highly recommend to go to my sourseforge page:
Thank You.

GNU ARM toolchain embedded development on Linux

There is a crying demand among mobile phone vendors for talented ARM programmers, and there's plenty of work to be done. This article provides a starting point for understanding the software side of embedded systems development by describing one set of commonly used tools: the GNU ARM toolchain.

About the program

The Calculus Integrator
So, what is The Calculus Integrator? This project was registered on on May 6, 2009.

It is just a simple program, with loads of functionality, that I am working on. As of right now, it can do very basic integrals, and that is it. It is a alpha release right now, but very stable. My program is licensed under Gnu Public licensed version

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