Showing posts from December, 2014

SystemD Debate and Configuration by Example

A "healthy" debate on the virtues, use-cases, and overall disdain and misconceptions of SystemD. Specific use-cases in "less-common" configurations provide a challenge as well as an opportunity to learn about the underlying mechanism of certain aspects of the Operating System. A substantial number of years working in/with Linux doesn't preclude a person from learning how to use new tools and mechanisms even if, or perhaps especially when, the mechanism is low-level software. Users and Administrators must not get so entrenched in their ways of comfort that they reject advancements in the underlying pieces of the OS on the basis of overestimating the merit of their own existing knowledge, while downplaying the benefits of the advancements and exaggerating their problems an perceived shortcomings on surface value. Nevertheless, even though change is inevitable in our universe, it breeds chaos in the early stages of wide-spread adaptation. It's in th

Recover Fedora21 after Removing swap LVM Partition

"God" help you if you make the mistake, as I did today on a newly-installed Fedora21 system, to delete an LVM swap partition without taking the proper precautions before rebooting. If you are in this position, or have been in the past, you've come face to face with the dracut rescue shell and its limited set of "shell" commands. While the rescue shell offers some potentially useful functions (commands), I could not successfully use it to implement any of the advised steps from manual pages and internet forums I came across when searching for a solution to this problem. The  Fedora Wiki page on "How to debug Dracut problems" suggested activating the root and any other logical volumes by executing  # lvm vgscan # lvm vgchange -ay "With the root volume available, you may continue booting the system by exiting the dracut shell" exit Though, in fairness, that resolution was dealing with unlocking an encrypted root volume with an addit

How to Reset Root Password in RHEL7

Without a doubt, one of the most powerful and essential tools a system's administrator has is the ability to gain root privileges. While it's generally a bad idea, to say the least, to perpetually operate as the root user on any given system, being able to log in as the root user on the command console is essential at times. Therefore, it's frustrating to be in the position as a system administrator if you've forgotten or otherwise lost the password and are, subsequently, unable to gain escalated privileges on a system. Since the shift to grub2, as well as other changes with the init system, the method of gaining access to a system for such low-level purposes has changed. Reboot the system, wait for the grub menu, press the letter 'E' on the keyboard to edit the menuentry. Then, scroll down to the bottom of the screen to the line starting with linux and append the space-separated kernel commands rw and init=/bin/bash before hitting the F10 key to boot

Backups in RHEL7 on XFS Filesystem

The default storage setup in a new Red Hat Enterprise Linux 7 installation is an LVM partitioning scheme with an XFS boot partition outside of the LVM scheme, and the root and home partitions comprising the main volume group on an XFS filesystem. This is a departure from the previous default filesystem type ext4 . Some important behavioral and administrative differences between the ext4 filesystem and the xfs filesystem are addressed in the RedHat Documentation, chapter 6 in the “Storage Administration Guide” specifically. The key items addressed pertain to Filesystem repair , Metadata error behavior , Quotas , Filesystem resize and Inode numbers among other things. One nice feature of the XFS filesystem is the native backup and restoration feature with the xfsdump and xfsrestore utilities, respectively. The xfsdump utility supports incremental backups to tape drives or regular file images. The incremental backups are possible due to the use of different dump levels .

Firefox--Multiple plugins Directories

There are a number of legitimate reasons why one would have multiple versions of Firefox installed on one system.  While, it's generally ill-advised to have multiple versions of the same package/software installed--as it could create resource conflicts and system hangups--recent versions of Firefox have become more stable in this type of scenario.  The Developer Edition of Firefox, for example, has an option under Preferences that specifies whether or not to "allow Firefox Developer Edition and Firefox to run at the same time" through the use of different Profiles . While this is a nice functionality, there are still some issues with the system-wide Library path and the local ".mozilla" directory in the user's home directory.  There's still an issue with installed plugins, which are in the system-wide directory "/usr/lib64/mozilla/plugins/" on a 64-bit system, not available in the second installed firefox package unless the user creates

Troubleshoot JavaScript Functionality--Firefox Browser and DD-WRT Network Router

HTML5 is here! On October 28th, 2014 the HTML Working Group published HTML5 as W3C Recommendation. This specification defines the fifth major revision of the Hypertext Markup Language (HTML), the format used to build Web pages and applications, and the cornerstone of the Open Web Platform. When the talk of HTML5 comes up generally it's understood that, for the most part, CSS3 and JavaScript are an intricate part of the "whole". Extended features such as responsive design among other things are nothing without all three languages. JavaScript in particular uproots the "operating system" and unshackles users from the confinement of locally-run software with seemingly boundless potential. Well, if that wasn't a loaded statement then you still have faith that I know what I'm talking about. Regardless, this post is mainly meant to help troubleshoot the possible causes of a half-assed web-experience followed by constant, nagging banners

Support Freedom and Net-Neutrality

---------- Forwarded message ---------- From:  +Evan Greer from FFTF   < > Date: Wed, Dec 17, 2014 at 9:14 AM Subject: "Impossible" To: Dear Fight for the Future member, I've got to be honest with you. I really didn't think we would make it this far. When we started this fight for net neutrality, it seemed like the odds were stacked impossibly against us. We're up against some of the most powerful and politically well-connected companies in the world. Companies that are so close to the government, sometimes it's hard to tell the two apart. But against all odds, we are winning. Everything we are hearing says the FCC is finally caving to the public pressure and writing a real net neutrality rule. Please help us finish the fight: click here to chip in whatever you can afford today. To tell the truth, when we first started this, there was a pretty strong voi

Set Focus to Follow Mouse Cursor in GNOME 3

Install dconf-editor in RHEL or Fedora, then go to org -> gnome -> desktop -> wm -> preferences and make sure auto-raise check-box is checked on. Also, change the focus-mode to sloppy or mouse . The window focus mode indicates how windows are activated. It has three possible values; "click" means windows must be clicked in order to focus them, "sloppy" means windows are focused when the mouse enters the window, and "mouse" means windows are focused when the mouse enters the window and unfocused when the mouse leaves the window. There's a nice, detailed write-up available on . Auto Raise Delay: The time delay before raising a window if auto-raise is set to true. The delay is given in thousandths of a second. Focus Mode: The window focus mode indicates how windows are activated. It has three possible values; “click” means windows must be clicked in order to focus them, “sloppy” means windows are focused when th

wpa_supplicant and wifi in RHEL 7

If you have a desktop environment set up in Red Hat Enterprise Linux 7, chances are that you might have GNOME installed as it is the "default".  NetworkManager is pulled in as a dependency package of GNOME and it's integrated into gnome-shell in the top panel as a widget.  While NetworkManager is a great tool as it consolidates many different networking tools and facilitates the network configuration for many different use-cases, there might be instances where its broad reach becomes an obstacle rather than a benefit to system administrators.  One such instance is when dealing with network bridging . Recently I was trying to set up a network bridge on my laptop, as it's equipped with a wifi adapter and an ethernet adapter, in order to dedicate the ethernet interface to a virtual machine in Red Hat 7 --or at least to "share" it.  Bridged networking (also known as physical device sharing) is used to dedicate a physical device to a virtual machine.  So,

Install NVidia drivers in RHEL

NVidia drivers for GPUs (Video Cards) are proprietary software and, therefore, are like a thorn in the eye of the OpenSource/Linux community. Given the nature of said drivers, Linux distributions do not provide support for nVidia's drivers; however, the nouveau project is an open-source alternative to nVidia's proprietary drivers, though it's still very much in development and 3D support, while it's greatly improved in recent years, is lacking. There are two ways to get the nVidia drivers installed onto a system running RedHat: Download the binary package directly from nvidia and execute the installation procedure with sh NVIDIA-Linux- .run Install the Community Enterprise Linux Repository elrepo and install the kmod-nvidia package yum install kmod-nvidia The second method is usually preferred as, similar to rpmfusion and Fedora , they are preformated in rpm format  they can be installed/updated/uninstalled with yum package manager are optimized

The New Meaning of Black Friday

Today, the day after Thanksgiving, "traditionally" known as Black Friday , is the busiest day for shopping in the United States. Though, most media outlets are flooded by incessant calls to run to the store and "SAVE!!", sporadic reports of nation-wide boycotts--in response to another unarmed African-American teenager's death at the hands of a police officer--do make it through to the occasional news-broadcast. It seems that the Black citizens of the United States came to know a different meaning of Black Friday ; one more synonymous with the dark, gloomy symbolism of all things black. While most Americans wrestled and pushed their way through long lines at the retail stores--the annual event provoking scenes eerily similar to those in apocalyptic movies--fighting for bargain prices on consumer products, the black "community", transfixed in a state of dejavu, wrestled with the idea of bargain-low prices of an African-American life. For

fail2ban configuration in Fedora/RHEL

The configuration files in Fedora20 for fail2ban are located in the /etc directory under /etc/fail2ban/ with further sub-directories for actions, filters and jails . drwxr -xr -x . 2 root 4.0 K May 16 2014 action . d drwxr -xr -x . 2 root 4.0 K Mar 19 2014 fail2ban . d drwxr -xr -x . 2 root 4.0 K May 16 2014 filter . d drwxr -xr -x . 2 root 4.0 K Mar 19 2014 jail . d -rw -r -- r -- . 1 root 2.1 K Mar 14 2014 fail2ban . conf -rw -r -- r -- . 1 root 33 Dec 10 00 : 16 fail2ban . local -rw -r -- r -- . 1 root 14 K Dec 10 01 : 06 jail . conf -rw -r -- r -- . 1 root 16 K Dec 10 00 : 54 jail . conf . rpmnew -rw -r -- r -- . 1 root 805 Dec 10 07 : 48 jail . local -rw -r -- r -- . 1 root 1.5 K Mar 14 2014 paths -common . conf -rw -r -- r -- . 1 root 606 Mar 14 2014 paths -debian . conf -rw -r -- r -- . 1 root 649 Mar 14 2014 paths -fedora . conf -rw -r -- r -- . 1 root 1.2 K Mar 14 2014