Sunday, September 29, 2013

CSSH on MacOS X 10.8+

I assume that you've already known what CSSH (or ClusterSSH in formal) is. In short, it is a way for control many Unix/Linux boxes in parallel in the same way.

I always use CSSH on my Fedora box at work, but this is the first time I have to use it at my home to control my cluster. And my laptop's operating system is Mac OS X 10.8. That is the problem.

Installation of CSSH on Mac OS X seems to be simple. If you want to do it in a lazy way like me, use port.

sudo port install cssh

Then, you try to connect to some host, for example.

cssh root@somehost

It should works well??? Oh no, some strange error message occur like the one as follows.

Can't connect to display `tmp/launch-P6rxkT/org.macosforge.xquartz:0': Invalid argument at /opt/local/lib/perl5/vendor_perl/5.12.4/X11/ line 2270

If you open file and go to line number 2270, you will see that it try to use INETSocket (wrong) instead of UNIXSocket (right). That is because $host is not equal to "unix". Now you have to change something here to let it use UNIXSocket by checking whether $host contains "xquartz" or not. You change the line number 2262 (the IF command before the error line) from

if ($host eq 'unix') {


if ($host eq 'unix' || index($host, "xquartz") != -1) {

(Ahh, that's the error of Perl 5.12.4 distribution of  Mac Ports.)

That's all. Let's try again and see everything goes well.

Wednesday, August 28, 2013

Supermicro Server: Reset the IPMI Password

You might sometime forget your IPMI password or you get the server from other and want to reset it? There are some options for you. However, first of all, you should try with the default IPMI account, which is ADMIN / ADMIN.


Supermicro provides a tool for you to manage your IPMI settings named IPMICFG. You can download it from the following location.

It contains tools for DOS, Linux, and Windows.


If you have Linux installed on that server, you can install OpenIPMI and IPMI Tool to manage the local or remote IPMI service.

To reset the password, all you have to do is as follows.

# service ipmi restart

If IPMI service could not be started, please stop here. You might not have IPMI support in your server.

First, you have to get the user id of the account "ADMIN".

# ipmitool user list

ID  Name      Callin  Link Auth IPMI Msg   Channel Priv Limit
2   ADMIN            true    false      false      Unknown (0x00)

You might see the output as above with the user id of account "ADMIN" is 2.

Now, you change the password of user with id = 2 to "MATKHAU", for example.

# ipmitool user set password 2 MATKHAU

That's all. Have a nice try!

Tuesday, August 13, 2013

RHEL/CentOS/Fedora: How to Disable CPU Frequency Scaling/Throttling

Attention! Be sure you REALLY want to perform this action! Do it at your own risk!

I assume that you may already know the reason before reaching my post. Run the following command as root. That's all.

echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor >& /dev/null

Have fun!!!

Thursday, July 4, 2013

Some post-installation steps to make Fedora 19 more comfortable

So, as you may now, Fedora 19 (Schrödinger’s Cat) has released for few days. And this time I decided to upgrade my PC immediately, and everything seems to be very smooth.

For Fedora, I have to make some minor changes to make it more comfortable, such as:
  • Install Liberation Fonts (version 2).
  • Fix the font's rendering problem.

Liberation Fonts

Liberation fonts are installed in Fedora by default. However, it is kept at version 1.07 with very poor quality. And to get the much better quality, I always upgrade them to version 2.

You can download compiled fonts from the Liberation Fonts page or RPM packages from Fedora's page. I choose the former method.

$ wget
$ tar -zxvf liberation-fonts-ttf-2.00.0.tar.gz
$ sudo cp -f liberation-fonts-ttf-2.00.1/*.ttf /usr/share/fonts/liberation/
$ sudo fc-cache

Now the Liberation fonts are ready to use. We will fix the font rendering problem before change font settings for GNOME to reflect what we have done so far.

Fix Font Rendering Problem

If you've ever see an Ubuntu screen, you may see a much better font rendering. The problem here is Fedora disable RGBA sub-pixel hinting. All you have to do is to enable such feature by install package freetype-freeworld from RPM Fusion.

$ rpm -ivh

Now, to change the default fonts and default font hinting methods for GNOME, you should install gnome-tweak-tool.

$ sudo yum install gnome-tweak-tool
$ gnome-tweak-tool &

Change the default font settings as in the below screen.

To make everything the same as Ubuntu, you should run the following command.

$ echo "Xft.lcdfilter: lcddefault" >> ~/.Xresources

You may need to log out and log in again to reflect the changes.