Monthly Archives: January 2018

Linux Foundation LFCS and LFCE: Alberto Bullo |

The Linux Foundation offers many resources for developers, users, and administrators of Linux systems. One of the most important offerings is the Linux Certification Program, which is designed to give you a way to differentiate yourself in today’s competitive job market.

How well does the certification prepare you for the real world? To illustrate that, The Linux Foundation will be featuring some recently certified admins and engineers. These testimonials should help you decide if either the Linux Foundation Certified System Administrator or the Linux Foundation Certified Engineer certification is right for you. In this article, we talk with Alberto Bullo, who recently completed the certification process for both LFCS (Ubuntu) and LFCE (CentOS). How did you become interested in Linux and open source?

Alberto Bullo: I started using Linux few years ago out of curiosity when my old computer started to get slow and wanted to try something lighter. At the time, I had a disk of Fedora lying around from a conference and managed to get it installed and working. Since then, I started using it for everyday tasks to get more familiar with the alternative software. I really liked the fact that I could select any distro I wanted and have full control of the operating system. I also used Linux for university projects and started to better understand how to use the utilities and services. Open source projects caught my attention when I started using them on my first job as they gave me the ability to adjust the features and code to my needs but also to contribute back to the community. I then started visiting open source conferences to get more involved and became a big fan of the initiative. What Linux Foundation course did you achieve certification in? Why did you select that particular course?

Bullo: I started with completing LFCS (Ubuntu) and achieved LFCE (CentOS) afterwards. I chose Linux Foundation certification because I like practical exams where you are in front of a terminal and reflect real-world scenario problems to be solved. This gives you the ability to think of multiple ways to solve a task but also how to find and understand the available documentation from the manual pages and help options. It’s a challenging test, and very different from traditional paper-based exams that I was accustomed to. What are your career goals? How do you see Linux Foundation certification helping you achieve those goals and benefiting your career?

Bullo: In the long run, I would like to become a system engineer or trainer. The Linux Foundation helped me build a solid foundation of how to manage and administer different systems and services that are crucial to achieve the goal and progress with my career. I am also planning to continue to work with other DevOps training provided by The Linux Foundation to extend my skills in development tools. What other hobbies or projects are you involved in? Do you participate in any open source projects at this time?

Bullo: I like home automation projects and am currently working on finding different solutions using open source software and micro-controllers. I participated twice in open source projects by raising bug reports, feature requests, and support on language-localization. Currently, I am working on university projects for academic research at the InSPIRE research center of UCLan University. I am looking forward to participating and being more involved in other projects in the near future. Do you plan to take future Linux Foundation courses? If so, which ones?

Bullo: I am currently interested in the Essentials of OpenStack Administration and Kubernetes Administration courses offered by The Linux Foundation. In what ways do you think the certification will help you as a systems administrator in today’s market?

Bullo: Being a hands-on test certificate reflecting real-world scenarios, it requires a solid understanding and a lot practice to pass the exam. The knowledge acquired by achieving the certification will help me troubleshoot and perform many system administration tasks in the work environment. Being also a vendor-independent test, it gives you the freedom to select from the available distributions that are more suitable and beneficial, based on your preference. As today’s technology is mostly based on Linux systems this is the perfect way to sharpen and gain necessary skills required to manage and deliver better results. What Linux distribution do you prefer and why?

Bullo: I am currently using Ubuntu and Fedora as my preferred desktop distributions due to the great communities around them, ease of use, and the long-term support they provide. I have been distro-hopping for some time trying out rolling release distributions like the openSUSE Tumbleweed and Arch Linux derivatives, as I like the idea of having updates as soon as they are released. To that end, I am using a mixture of different distros at home right now. For server use, I tend to prefer CentOS as its very well documented and stable. Are you currently working as a Linux systems administrator? If so, what role does Linux play?

Bullo: Sadly, I am still not working as a Linux system administrator but my role requires me to troubleshoot issues which need Linux knowledge as most, if not all, of our servers are Linux based.

There were instances where I put into practice what I have learned about how to identify system issues, so Linux plays a very important role on my everyday tasks. Where do you see the Linux job market growing the most in the coming years?

Bullo: I am sure anything related to Linux will grow exponentially in the coming years, especially with the continued rise of cloud technologies. Companies are continuously developing and utilizing open source software for their needs and benefiting from the great community behind them. Small businesses and startups are also enjoying the ability to scale fast with the open source technologies and started transitioning to Linux based solutions. What advice would you give those considering certification for their preparation?

Bullo: Practice a lot on a virtual environment. The exams are going to test your knowledge of finding possible problems that prevent you from completing the tasks and require you to find documentation and/or configurations needed to achieve the goal at hand. Don’t be limited to the certification domains but also try to understand the technology behind it, that will make it easier for you to troubleshoot in case you are not able to perform a task on the exam. This is especially true for the LFCE certification, which requires you to know the services and have a solid understanding of the available options. Don’t be limited by studying from one source; there are multiple books available that cover the services and system admin tasks needed to pass and gain the necessary knowledge. If you have found employment in the IT industry, do you feel like your certification was crucial or beneficial?

Bullo: The course handbooks for both the LFCE and LFCS exams reflect a lot of services that are used in a real work environment. I have no doubt that the certification is beneficial to troubleshoot and perform daily tasks but also in helping with Linux-related questions raised in an interview.

Learn more about Linux through the free “Introduction to Linux” course from The Linux Foundation and edX.
Read more:

Linux Foundation LFCS and LFCE: Miltos Tsatsakis

Linux Foundation Certified System Administrator: Gabriel Rojo Argote

Linux Foundation LFCE Georgi Yadkov Shares His Certification Journey

Linux Foundation LFCS and LFCE: Pratik Tolia

Linux Foundation Certified Engineer: Gbenga “Christopher” Adigun

Linux Foundation Certified Engineer: Karthikeyan Ramaswamy

Linux Foundation Certified System Administrator: Muneeb Kalathil

Install Icinga 2 and Icinga web 2 on Ubuntu 17.10 server

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Icinga 2 is an open source monitoring system which checks the availability of your network resources, notifies users of outages and generates performance data for reporting.Scalable and extensible, Icinga2 can monitor large, complex environments across multiple locations.

Icinga Web 2 is a powerful PHP framework for web applications that comes in a clean and reduced design. It’s fast, responsive, accessible and
easily extensible with modules.

Preparing your system

Before installing Icinga 2 you need to make sure you have installed Ubuntu 17.10 LAMP server.

Install Icinga 2 on ubuntu 17.10

From the terminal run the following command

sudo apt-get install icinga2 icinga2-ido-mysql

This will install the main Icinga software, along with a database driver that enables Icinga to put historical data and other information into a MySQL database.

You will be presented with the following questions

Enable Icinga 2’s ido-mysql feature? YES

Configure database for icinga2-ido-mysql with dbconfig-common? YES

You’ll then be prompted to set up an Icinga database password. Create a strong password and record it for later. We’ll need it when setting up
the web interface.

Now you need to enable icinga2 mysql feature using the following commands

sudo icinga2 feature enable ido-mysql

sudo icinga2 feature enable command

sudo systemctl restart icinga2

If you don’t do the above steps you will be presented with the following error

There is currently no icinga instance writing to the IDO. Make sure that a icinga instance is configured and able to write to the IDO

Check the status of icinga2 using the following command

sudo systemctl status icinga2

Installing the Icinga2 Web Interface

Run the following command to install Icinga2 Web Interface

sudo apt-get install icingaweb2

Now you need to edit the /etc/php/7.1/apache2/php.ini file to enter the timezone

sudo nano /etc/php/7.1/apache2/php.ini

Add the time zone

date.timezone = Europe/London

Save and exit the file and restart the apache2 server using the following command

sudo systemctl restart apache2

Setting up the Icinga2 Web Interface

We need to configure the Icinga2 Web Interface using the web-based process before starting this we need to create setup token using the following command

sudo icingacli setup token create

You need to start the web interface using the following link


Setting up the Token

Enter the token created previously and click next

Selecting the Icinga Web2 Modules

Enabling the Monitoring module and Click Next to continue

Verifying the PHP settings

Authenticating Method select as database

Enter the Database details

Creating Icinga2 Web administration logins

Choosing the Application configuration options

Review all the selected settings

Configuring Monitoring Module

Review monitoring module configuration options

Icinga2 Login Interface

Once you login you should see similar to the following screen

After completing the installation check the icinga2 documentation for hosts monitoring setup.

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Install Cacti on ubuntu 17.10 server

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Cacti is a complete network graphing solution designed to harness the power of RRDTool’s data storage and graphing functionality. Cacti provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features out of the box. All of this is wrapped in an intuitive, easy to use interface that makes sense for LAN-sized installations up to complex networks with thousands of devices.



Unlimited number of graph items can be defined for each graph optionally utilizing CDEFs or data sources from within cacti.
Automatic grouping of GPRINT graph items to AREA, STACK, and LINE[1-3] to allow for quick re-sequencing of graph items.
Auto-Padding support to make sure graph legend text lines up.
Graph data can be manipulated using the CDEF math functions built into RRDTool. These CDEF functions can be defined in cacti and can be used globally on each graph.
Support for all of RRDTool’s graph item types including AREA, STACK, LINE[1-3], GPRINT, COMMENT, VRULE, and HRULE.

Data Sources

Data sources can be created that utilize RRDTool’s “create” and “update” functions. Each data source can be used to gather local or remote data and placed on a graph.
Supports RRD files with more than one data source and can use an RRD file stored anywhere on the local file system.
Round robin archive (RRA) settings can be customized giving the user the ability to gather data on non-standard timespans while store varying amounts of data.

Data Gathering

Contains a “data input” mechanism which allows users to define custom scripts that can be used to gather data. Each script can contain arguments that must be entered for each data source created using the script (such as an IP address).
Built in SNMP support that can use php-snmp, ucd-snmp, or net-snmp.
Ability to retrieve data using SNMP or a script with an index. An example of this would be populating a list with IP interfaces or mounted partitions on a server. Integration with graph templates can be defined to enable one click graph creation for hosts.
A PHP-based poller is provided to execute scripts, retrieve SNMP data, and update your RRD files.


Graph templates enable common graphs to be grouped together by templating. Every field for a normal graph can be templated or specified on a per-graph basis.
Data source templates enable common data source types to be grouped together by templating. Every field for a normal data source can be templated or specified on a per-data source basis.
Host templates are a group of graph and data source templates that allow you to define common host types. Upon the creation of a host, it will automatically take on the properties of its template.

Graph Display

The tree view allows users to create “graph hierarchies” and place graphs on the tree. This is an easy way to manage/organize a large number of graphs.
The list view lists the title of each graph in one large list which links the user to the actual graph.
The preview view displays all of the graphs in one large list format. This is similar to the default view for the 14all cgi script for RRDTool/MRTG.

User Management

User based management allows administrators to create users and assign different levels of permissions to the cacti interface.
Permissions can be specified per-graph for each user, making cacti suitable for co location situations.
Each user can keep their own graph settings for varying viewing preferences.

Preparing your system

Before installing cacti you need to make sure you have installed Ubuntu 17.10 LAMP server.

Install Cacti on ubuntu 17.10 server

Open the terminal and run the following command

sudo apt-get install snmp snmpd cacti rrdtool cacti-spine

The above command starts the cacti installation.

Now select the webserver you want to use (in my case it is apache2)


Cacti database configurations select yes


Enter database admin user password

Mysql application password for cacti


confirm the password

THis will complete the Cacti installation.

 Login in to cacti

Point your web browser towards http://YOURSERVERIP/cacti/  and  login in to Cacti with the default admin/admin, and change the password to something more sensible



After login in to Cacti you should see similar to the following screen

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How to fix DNS problems after upgrading Ubuntu 17.10 from ubuntu 17.04/16.10/16.04

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One of my friend recently upgraded his ubuntu 17.04 to ubuntu 17.10 and after the upgrade my DNS stopped working.

Use one of the solutions to fix DNS issue on Ubuntu 17.10

Solution 1

Add the google DNS server in /etc/systemd/resolved.conf file

sudo nano /etc/systemd/resolved.conf

add the following line


Save and exit the file

Restart the systemd-resolved using the following command

sudo systemctl restart systemd-resolved

Solution 2

Edit the /etc/NetworkManager/NetworkManager.conf file

sudo nano /etc/NetworkManager/NetworkManager.conf





restart NetworkManager using the following command

sudo systemctl restart NetworkManager

Solution 3

Edit /etc/nsswitch.conf file

sudo nano /etc/nsswitch.conf

comment out the following line

hosts: files

Save and exit the file

Solution 4

add a line nameserver in /etc/resolv.conf

Install unbound with sudo apt-get install unbound

disable the troublesome daemon with:

sudo systemctl disable systemd-resolved

sudo systemctl stop systemd-resolved

add dns=unbound in the [main] section of


enable unbound with:

sudo systemctl enable unbound-resolvconf

sudo systemctl enable unbound

Reboot the ubuntu PC/server

If you can share which solution worked for you is very useful for other users and if you have any other new solution that would help more users.

Note:- Some of the solutions are from askubuntu

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Multimedia Apps for the Linux Console |

When last we met, we learned that the Linux console supports multimedia. Yes, really! You can enjoy music, movies, photos, and even read PDF files without being in an X session with MPlayer, fbi, and fbgs. And, as a bonus, you can enjoy a Matrix-style screensaver for the console, CMatrix.

You will probably have make some tweaks to your system to make this work. The examples used here are for Ubuntu Linux 16.04.


You’re probably familiar with the amazing and versatile MPlayer, which supports almost every video and audio format, and runs on nearly everything, including Linux, Android, Windows, Mac, Kindle, OS/2, and AmigaOS. Using MPLayer in your console will probably require some tweaking, depending on your Linux distribution. To start, try playing a video:

$ mplayer 

If it works, then hurrah, and you can invest your time in learning useful MPlayer options, such as controlling the size of the video screen. However, some Linux distributions are managing the framebuffer differently than in the olden days, and you may have to adjust some settings to make it work. This is how to make it work on recent Ubuntu releases.

First, add yourself to the video group.

Second, verify that /etc/modprobe.d/blacklist-framebuffer.conf has this line: #blacklist vesafb. It should already be commented out, and if it isn’t then comment it. All the other module lines should be un-commented, which prevents them from loading. Side note: if you want to dig more deeply into managing your framebuffer, the module for your video card may give better performance.

Add these two modules to the end of /etc/initramfs-tools/modules, vesafb and fbcon, then rebuild the initramfs image:

$ sudo nano /etc/initramfs-tools/modules
    # List of modules that you want to include in your initramfs.
    # They will be loaded at boot time in the order below.
$ sudo update-initramfs -u

fbcon is the Linux framebuffer console. It runs on top of the framebuffer and adds graphical features. It requires a framebuffer device, which is supplied by the vesafb module.

Now you must edit your GRUB2 configuration. In /etc/default/grub you should see a line like this:


It may have some other options, but it should be there. Add vga=789:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash vga=789"

Reboot and enter your console (Ctrl+Alt+F1), and try playing a video. This command selects the fbdev2 video device; I haven’t learned yet how to know which one to use, but I had to use it to play the video. The default screen size is 320×240, so I scaled it to 960:

$ mplayer -vo fbdev2 -vf scale -zoom -xy 960

And behold Figure 1. It’s grainy because I have a low-fi copy of this video, not because MPlayer is making it grainy.

MPLayer plays CDs, DVDs, network streams, and has a giant batch of playback options, which I shall leave as your homework to explore.

fbi Image Viewer

fbi, the framebuffer image viewer, comes in the fbida package on most Linuxes. It has native support for the common image file formats, and uses convert (from Image Magick), if it is installed, for other formats. Its simplest use is to view a single image file:

$ fbi filename

Use the arrow keys to scroll a large image, + and – to zoom, and r and l to rotate 90 degress right and left. Press the Escape key to close the image. You can play a slideshow by giving fbi a list of files:

$ fbi --list file-list.txt

fbi supports autozoom. With -a fbi controls the zoom factor. --autoup and --autodown tell fbi to only zoom up or down. Control the blend time between images with --blend [time], in milliseconds. Press the k and j keys to jump behind and ahead in your file list.

fbi has commands for creating file lists from images you have viewed, and for exporting your commands to a file, and a host of other cool options. Check out man fbi for complete options.

CMatrix Console Screensaver

The Matrix screensaver is still my favorite (Figure 2), second only to the bouncing cow. CMatrix runs on the console. Simply type cmatrix to start it, and Ctrl+C stops it. Run cmatrix -s to launch it in screensaver mode, which exits on any keypress. -C changes the color. Your choices are green, red, blue, yellow, white, magenta, cyan, and black.

CMatrix supports asynchronous key presses, which means you can change options while it’s running.

-B is all bold text, and -B is partially bold.

fbgs PDF Viewer

It seems that the addiction to PDF documents is pandemic and incurable, though PDFs are better than they used to be, with live hyperlinks, copy-paste, and good text search. The fbgs console PDF viewer is part of the fbida package. Options include page size, resolution, page selections, and most fbi options, with the exceptions listed in man fbgs. The main option I use is page size; you get -l, xl, and xxl to choose from:

$ fbgs -xl annoyingpdf.pdf

Learn more about Linux through the free “Introduction to Linux” course from The Linux Foundation and edX.