Wednesday, February 7, 2018

Nested virtualization on AMD ThreadRipper on Fedora 27

After much testing different kernel parameters and many emails between me and one of the kernel devs at Red Hat (I work there), I found a very simple solution to implementing nested virtualization on AMD ThreadRipper on Fedora 27.

Just run the 4.13 kernel for now. Everything works fine on 4.13. It turns out that 4.14 is broken for nested virt. That's all :/

Friday, January 12, 2018

Using a AMD Ryzen ThreadRipper with Fedora 27

Here's a collection of things that are useful to know if you are using a Ryzen ThreadRipper processor with Fedora.

  • SVM works fine, nSVM currently does not. However, virt-manager on Fedora 27 wants to use the EPYC processor type. This gives me odd warnings in dmesg, like

    smpboot: do_boot_cpu failed(-1) to wakeup CPU#1

    To get rid of these, I use Opteron_G2 as my processor type, which seems to work fine.
  • on the MSI x399 mainboard, if you want to read out your hardware sensors, you have to:

modprobe nct6775 force_id=0xd352

If you want to keep this after a reboot, do:

echo "options nct6775 force_id=0xd352" > /etc/modprobe.d/nct6775.conf
echo "nct6775" > /etc/modules-load.d/nct6775.conf

More to come :)

Thursday, July 7, 2016

Why haven't I ever done this before??

This is going to be a short one.

If you are on Fedora, please go and read this post on, and do as it says. It makes a world of difference for how your fonts look. For the better. Go do it now.

Tuesday, August 4, 2015

Building an Arch Linux Docker base image for your Raspberry Pi 2

So I wanted to toy around a bit with my Raspberry Pi 2 running some Docker containers.

I did not, however, wanted to download some ready made base image. First of all, I don't know where it has been, who made it and whether what's in there is legit. Second, the base images out there seem to be based on the Raspberry Pi 2 operating system images and about twice the size they should be (over 500MiB instead of about 250MiB).

So I set off to create my own Raspberry Pi 2 base image (armv7h) for Arch Linux. These are my notes to make this a bit easier you than it was for me.

There is this file you need to download, together with this file. Put them in a directory together. I like to edit the second one to show the correct architecture (armv7h on line 22), but that's not strictly necessary.

What *is* strictly necessary though, is to edit the first file and edit line 56, which currently reads 
set timeout 60
 and change that to something like
set timeout 300
This is because the 60 second timeout that is there by default is fine for fast disks in x86_64 machines, but will not do for your Pi 2. The timeout should accomodate for the pacstrap command to finish, which installs about 86 packages. Even with a fast SD card in your Pi 2, 60 seconds will not cut it.

If you up the timeout to 300, the process will complete nicely, giving you a proper armv7h Docker base image!

Second thing you will want to do, is to edit the file again and change line 71 where it reads
Server =\$repo/os/\$arch
Server =\$arch/\$repo
If you don't make that change, you'll never be able to install packages from the armv7h repositories.

Now go and run
Happy containering! :)

Sunday, March 23, 2014

Belastingaangifte 2013 op Fedora

Wat een verademing :)

Dit jaar is het de belastingdienst in Nederland voor het eerst gelukt om een nette (althans, redelijke nette) RPM te maken voor het aangifteprogramma op Linux!

RPM downloaden, installeren en hoppa! Nou ja, dat zou het zijn althans, als dat programma vlak voor het verzenden van je aangifte niet ongegeneerd zou segfaulten met must be installed for pthread_cancel to work
Aborted (core dumped)
Beetje slordig, maar redelijk simpel op te lossen met
sudo dnf -y install libgcc.i686
Kan natuurlijk ook met yum ;)

De foutmelding treedt alleen op als je je aangifte op een x86_64 systeem in wilt vullen, waarop libgcc niet in 32-bit variant geinstalleerd is.

Wednesday, August 14, 2013

"Windows is unable to install to the selected location. Error: 0x80300001"

So I was playing with RHEV the other day and having some problems installing Windows 7 in a VM.

The error I received was:

"Windows is unable to install to the selected location. Error: 0x80300001"


The cause apparently is the fact that the install disk is missing from the drive. Ok, my bad: I had to take it out (virtually) to install the Virtio drivers. But is it really that difficult to write an understandable error message? What is wrong with: "The install disk is not in the drive.". Sheesh.


Tuesday, March 5, 2013

Belastingaangifte doen met Fedora 18

Als je belastingaangifte wilt doen op Linux, op Fedora 18 x86_64 om meer precies te zijn, en je hebt een vrij minimale installatie gedaan, krijg je allerlei foutmeldingen tijdens het starten van het aangifte programma omtrent missende libraries. Vooral de eerste is cryptisch:

bash: ./ib2012ux: /lib/ bad ELF interpreter: No such file or directory

Die duidt doorgaans op het ontbreken van 32-bits libraries op een 64-bits systeem. Los het hele probleem op door het volgende commando uit te voeren:

sudo yum -y install glibc.i686 libXext.i686 libSM.i686

Hierna is alle software die nodig is om ib2012ux uit te voeren, aanwezig.