Skip to main content

You are here


Restoring access to Fedora after Ubuntu upgrade

I have a quadroboot OS installation environment in my primary laptop.

  • Ubuntu (primary OS)
  • Kali
  • Fedora
  • Windows 7

I decided to upgrade my Ubuntu installing to the latest 15.04. As soon the upgrade completed and rebooted, I noticed the GRUB menu was no longer displaying my Fedora 21 environment. The problem was because I had installed Fedora under an LVM partition, while the others weren't.

Restoring boot access to Fedora was fairly simple.

First, I had install lvm2 package in Ubuntu so it's able to view and configure the LVM

[email protected]:~$ sudo apt-get install lvm2

Then I had to activate the Volume Group.

[email protected]:~$ sudo vgchange -a y

After updating the Volume Group, I was able to verify that Ubuntu was able to my Fedora 21 install.

[email protected]:~$ sudo os-prober
/dev/sda1:Windows 7 (loader):Windows:chain
/dev/sda6:Debian GNU/Linux (Kali Linux 1.0):Debian:linux
/dev/mapper/fedora-root:Fedora release 21 (Twenty One):Fedora:linux

So the last step was to generate a new grub config.

[email protected]:~$ sudo grub-mkconfig > /boot/grub/grub.cfg


Awesome Applications: 

Installing system-config-kickstart on Ubuntu

So, system-config-kickstart fails to start after the initial install.


[email protected]:~$ system-config-kickstart
Traceback (most recent call last):
File "/usr/share/system-config-kickstart/", line 92, in
File "/usr/share/system-config-kickstart/", line 131, in __init__
self.X_class = xconfig.xconfig(xml, self.kickstartData)
File "/usr/share/system-config-kickstart/", line 80, in __init__
File "/usr/share/system-config-kickstart/", line 115, in fill_driver_list
raise RuntimeError, (_("Could not read video driver database"))
RuntimeError: Could not read video driver database

Downgrade the hwdata package.

# apt-get remove hwdata
# wget
# dpkg -i hwdata_0.234-1_all.deb
# apt-mark hold hwdata
# apt-get install system-config-kickstart

This is a known bug in Ubuntu that is yet to be fixed...


Awesome Applications: 

Black background in all desktops after Ubuntu 13.10 upgrade

So I just upgraded my Dell XPS 13 laptop from Ubuntu 13.04 to 13.10, and immeditely the first thing I noticed that all of my desktops had a black background. and manually changing the background wallpaper took no effect. Turns out this is a common problem. In my case it turned out to be related to Gnome, which I found it to be rather interesting giving that a Gnome specific setting will case this in Unity.

gsettings set org.gnome.settings-daemon.plugins.background active true



Awesome Applications: 

Chef encountered an error attempting to create the client

So I'm finally starting to keep up with modern times and started to learn Chef more in depth. My goal is to completely automate and easily manage all of virtual machine instances running in my home network.

Upon attempting to bootstrap my very first node, I received the following error:

ubuntu Creating a new client identity for ubuntu01 using the validator key.
ubuntu ===================================================================
ubuntu Chef encountered an error attempting to create the client "ubuntu01"
ubuntu ===================================================================
ubuntu Resource Not Found:
ubuntu -------------------
ubuntu The server returned a HTTP 404. This usually indicates that your chef_server_url is incorrect.
ubuntu Relevant Config Settings:
ubuntu -------------------------
ubuntu chef_server_url ""
ubuntu [2013-09-15T22:25:28-07:00] FATAL: Stacktrace dumped to /var/chef/cache/chef-stacktrace.out
ubuntu Chef Client failed. 0 resources updated
ubuntu [2013-09-15T22:25:28-07:00] FATAL: Chef::Exceptions::ChildConvergeError: Chef run process exited unsuccessfully (exit code 1)

This essentially means that the node is not able to communicate with the Chef server. In my case, it turned out that the ubuntu01 machine was not using my local DNS servers, thus the lookup from the machine was failing.


Awesome Applications: 

Can't locate local/ CPAN error on Ubuntu 12.04

So the default Perl installation that ships with Ubuntu 12.04 LTS, does not include local::lib which is necessary if you want to use CPAN.


Can't locate local/ in @INC (@INC contains: /home/tony/perl5/lib/perl5 /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 /usr/local/lib/site_perl /home/tony) at /usr/share/perl/5.14/CPAN/ line 1300.


sudo apt-get install liblocal-lib-perl




ZFS on Linux: Kernel updates

Just as I would expect, updating both the kernel's of the machine that is running VirtualBox and its virtual machines and the ZFS enabled Linux virtual machine was completed with absolutely no issues. I originally was more concern on updating the host VirtualBox machine's kernel given that I've never really done this in the past using the additional VirtualBox Extension Pack add-on before, on the other hand I wasn't to concern regarding the ZFS kernel module, given that it was installed as part of a dkms kernel module rpm. Which regardless of what people think about dkms modules, as a sysadmin that have worked with Linux systems with them (proprietary), it's certainly a relief knowing that little or no additional work is needed to rebuild the respective module after updating to a newer kernel.


Awesome Applications: 

ZFS on Linux: Storage setup

For my media storage, I'm using a 500GB 5400 RPM USB drive. Since my Linux ZFS backup server is a virtual machine under VirtualBox, in order for the VM to be able to access the entire USB drive completely, the VirtualBox Extension Pack add-on needs to be installed.

The VirtualBox Extension Pack for all versions can be found on the following web site . It is important that the Extension Pack installed must be for the same version as VirtualBox.

VirtualBox about

VBoxManage extpack install Oracle_VM_VirtualBox_Extension_Pack-4.1.12.vbox-extpack

Additionally, it is also important that the user which VirtualBox will run under is member of the vboxusers group.

groups tony
tony : tony adm cdrom sudo dip plugdev lpadmin sambashare
sudo usermod -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,vboxusers tony
groups tony
tony : tony adm cdrom sudo dip plugdev lpadmin sambashare vboxusers

Since my computer is already using two other 500GB external USB drives, I had to properly identify the drive that I wanted to use for my ZFS data. This was a really simple process (I don't give a flying fuck about sharing my drive's serial).

sudo hdparm -I /dev/sdd|grep Serial
Serial Number: J2260051H80D8C
Transport: Serial, ATA8-AST, SATA 1.0a, SATA II Extensions, SATA Rev 2.5, SATA Rev 2.6; Revision: ATA8-AST T13 Project D1697 Revision 0b

Now that I know the serial number of the USB drive, I can configure my VirtualBox Linux ZFS server VM to automatically use the drive.
VirtualBox drive configuration

At this point I'm about to use the 500 GB hard drive as /dev/sdb under my Linux ZFS server and use it to create ZFS pools and file systems.

zpool create pool backups /dev/sdb
zfs create backups/dhcp

Since I haven't used ZFS on Linux extensively before, I'm manually mounting my ZFS pool after a reboot.

[email protected] ~]# df -h
Filesystem Size Used Avail Use% Mounted on
3.5G 1.6G 1.8G 47% /
tmpfs 1.5G 0 1.5G 0% /dev/shm
/dev/sda1 485M 67M 393M 15% /boot
[[email protected] ~]# zpool import
pool: backups
id: 15563678275580781179
state: ONLINE
action: The pool can be imported using its name or numeric identifier.

backups ONLINE
[[email protected] ~]# zpool import backups
[[email protected] ~]# df -h
Filesystem Size Used Avail Use% Mounted on
3.5G 1.6G 1.8G 47% /
tmpfs 1.5G 0 1.5G 0% /dev/shm
/dev/sda1 485M 67M 393M 15% /boot
backups 446G 128K 446G 1% /backups
backups/afs 447G 975M 446G 1% /backups/afs
backups/afs2 447G 750M 446G 1% /backups/afs2
backups/bashninja 448G 1.4G 446G 1% /backups/bashninja
backups/debian 449G 2.5G 446G 1% /backups/debian
backups/dhcp 451G 4.4G 446G 1% /backups/dhcp
backups/macbookair 446G 128K 446G 1% /backups/macbookair
backups/monitor 447G 880M 446G 1% /backups/monitor
backups/monitor2 446G 128K 446G 1% /backups/monitor2
446G 128K 446G 1% /backups/
backups/rubysecurity 447G 372M 446G 1% /backups/rubysecurity
backups/solaris 446G 128K 446G 1% /backups/solaris
backups/ubuntu 446G 128K 446G 1% /backups/ubuntu


Awesome Applications: 

Monitoring computer's temperature with lm_sensors

One of the primary reasons I use SSD drives on both of my Mac Minis that I use as hypervisors (besides speed), is that compared to regular hard drives, SSD drives consume far less power and more importantly generate less heat. Before using SSD drives on my machines, the fan noise both of them made during the middle of summer was pretty evident compared to any other time during the year.

Although at the time I did little research about proactively monitoring the temperature of my machines, now thanks to the Nagios book that I'm currently reading, I learned about the tool lm-sensors, which is available to monitor the hardware temperature in Linux.

Installing lm-sersors in Ubuntu Server 12.04 is really simple.

sudo apt-get install libsensors4 libsensors4-dev lm-sensors

Since lm-sensors requires low-level hooks to monitor hardware temperate, it comes with the utility sensors-detect, which can be used to automatically detect and load the appropriate kernel modules for the lm-sensors tool to function on the respective piece of hardware.

[email protected]:~$ sudo sensors-detect
# sensors-detect revision 5984 (2011-07-10 21:22:53 +0200)
# System: Apple Inc. Macmini5,1
# Board: Apple Inc. Mac-8ED6AF5B48C039E1

This program will help you determine which kernel modules you need
to load to use lm_sensors most effectively. It is generally safe
and recommended to accept the default answers to all questions,
unless you know what you're doing.

Some south bridges, CPUs or memory controllers contain embedded sensors.
Do you want to scan for them? This is totally safe. (YES/no): YES

In the case of my mid 2011 Apple Mac Minis, it was only able to use the coretemp module. File /etc/modules :

# Generated by sensors-detect on Sat Feb  2 21:22:20 2013
# Chip drivers

After the module has been added, then its just a matter of loading the recently applied modules.

Do you want to add these lines automatically to /etc/modules? (yes/NO)yes

Monitoring programs won't work until the needed modules are
loaded. You may want to run 'service module-init-tools start'
to load them.

Unloading i2c-dev... OK
Unloading i2c-i801... OK
Unloading cpuid... OK

[email protected]:~$ sudo service module-init-tools start
module-init-tools stop/waiting
[email protected]:~$

Now that the appropiate kernel modules have been loaded. I have everything needed to check the temperature.

[email protected]:~$ sensors
Adapter: ISA adapter
Physical id 0: +49.0°C (high = +86.0°C, crit = +100.0°C)
Core 0: +48.0°C (high = +86.0°C, crit = +100.0°C)
Core 1: +50.0°C (high = +86.0°C, crit = +100.0°C)

Adapter: ISA adapter
Exhaust : 1801 RPM (min = 1800 RPM)
TA0P: +36.0°C
TA0p: +36.0°C
TA1P: +34.8°C
TA1p: +34.8°C
TC0C: +47.0°C
TC0D: +44.8°C
TC0E: +57.5°C
TC0F: +58.5°C
TC0G: +94.0°C
TC0J: +0.8°C
TC0P: +42.5°C
TC0c: +47.0°C
TC0d: +44.8°C
TC0p: +42.5°C
TC1C: +50.0°C
TC1c: +50.0°C
TCFC: +0.2°C
TCGC: +49.0°C
TCGc: +49.0°C
TCPG: +98.0°C
TCSC: +50.0°C
TCSc: +50.0°C
TCTD: +255.5°C
TCXC: +49.5°C

Of course, I just had to write a Nagios plugin to monitor them:

#!/usr/bin/env perl
use strict;
# Tony Baltazar. root[@]

use constant OK => 0;
use constant WARNING => 1;
use constant CRITICAL => 2;
use constant UNKNOWN => 3;

my %THRESHOLDS = (OK => 70, WARNING => 75, CRITICAL => 86);

# Sample output
#Physical id 0:  +55.0°C  (high = +86.0°C, crit = +100.0°C)
#Core 0:         +54.0°C  (high = +86.0°C, crit = +100.0°C)
#Core 1:         +55.0°C  (high = +86.0°C, crit = +100.0°C)
my @get_current_heat = split "\n", `sensors 2>/dev/null|grep -E -e '(Physical id 0|Core [0-1])'`;

my $counter = 0;
my $output_string;

for my $heat_usage_per_core (@get_current_heat) {
	$heat_usage_per_core =~ /(.*):\s+\+([0-9]{1,3})/;
	my $core = $1;
	my $temp = $2;
	if ($temp < $THRESHOLDS{OK}) {
		$output_string .= "$core - temperature : $temp" . 'C | ';
	} elsif ( ($temp > $THRESHOLDS{OK}) && ($temp >= $THRESHOLDS{WARNING}) && ($temp < $THRESHOLDS{CRITICAL}) ) {
		print "WARNING! $core temperature: $temp\n";
	} elsif ( ($temp > $THRESHOLDS{OK}) && ($temp > $THRESHOLDS{WARNING}) && ($temp >= $THRESHOLDS{CRITICAL}) ) { 
		print "CRITICAL! $core temperature: $temp\n";

if ($counter == 3 ) {
	print $output_string;
} else {
	print "Unable to get all CPU's temperature.\n";



Awesome Applications: 

Configuring Ubuntu server to automatically email package update notices

Apticron will give you the ability to automatically email information about any packages on a Ubuntu system that needs to be updated.

Installing it and configuring it, is dead simply that even my six year old nephew can do it.

sudo apt-get install apticron

Now simply update the /etc/apticron/apticron.conf config with your email address. By default the cron entry gets added to run every day, /etc/cron.daily/apticron .

Unlike Red Hat's yum-updatesd utility, the apticron tool also includes a summary information about the package's update changes.


Premium Drupal Themes by Adaptivethemes