Postings by Niki Kovacs

CentOS 7 + KDE: Okular view PDF files OK but prints a blank page


I recently installed CentOS 7 + KDE 4.14 on my main workstation, and
overall I'm very happy with it.

Okular seems to have trouble with some PDF files. I'm using the Dolibarr
application to generate invoices. I can view the resulting PDF file OK,
but when I try to print it, I get a blank page. A few days ago I had a
similar problem with a PDF file generated from a french administration
online form.

On my previous installation (Slackware64 14.1 + Xfce + Evince built from
source) I never had any trouble with PDF files.

Any suggestions?


Niki Kovacs

Virt-Manager and full-screen display


I have CentOS 7 with Qemu/KVM and Libvirt running on a headless HP
Proliant Server. Virtual hosts are managed via Virt-Manager installed on
a CentOS 7 + KDE client via SSH.

Things are running quite nicely for now, I only have a few small minor
details to adjust.

On my main workstation running Slackware64 14.1, I also have Qemu/KVM
and Virt-Manager installed. When I launch a virtual host and switch to
full-screen display, the host is a "real" full screen.

But when I do the same thing with CentOS, I don't have a real
full-screen display.

rpcbind fails to start after creating virbr0 bridge


In my office I have an HP Proliant server running CentOS 7. It's a
minimal install without GUI. The machine has two network interface
cards, and for now it's acting as gateway/firewall, and it's running
ntpd, Dnsmasq and Rsnapshot.

I'd like this machine to also be a KVM virtualization host, so I
installed qemu-kvm and libvirt.

SAN certificates for multiple domains and multiple services


I'm currently installing and configuring CentOS 7 on a public server.
The machine will host a few small-to-midsize projects that are currently
running on a handful of Slackware servers: public library databases, our
public school's agenda, a small webradio, OwnCloud for myself and a
local non-profit, etc.

Until recently I've mostly used self-signed SSL certificates for stuff
needing a secure connection.

Apache + SSL: default configuration rated "C" by Qualys Labs


I'm currently experimenting with a public server running CentOS 7. I
have half a dozen production servers all running Slackware Linux, and I
intend to progressively migrate them to CentOS, for a host of reasons
(support cycle, package availability, SELinux, etc.) But before doing
that, I have to figure out a few things that work differently under

CentOS 7 + HPLIP = blank page


I just installed CentOS 7 + KDE on a new workstation in my office. I
tried to setup my printer, but the test page is blank. Here's some details.

The printer is an HP OfficeJet 8600 Pro. It works perfectly with all
other desktop clients running Slackware Linux and HPLIP.

I installed hplip and hplip-gui, launched HP Toolbox and then setup the
printer - a network printer - which is mainly a matter of confirming OK,

The printer shows up OK in HP Toolbox, but when I try to print a test
page, the printer ejects a blank page, that's it.

Which leaves me clueless.


Niki Kovacs

bind vs. bind-chroot


On my public servers, I usually run BIND for DNS. I see CentOS offers a
preconfigured (sort of) bind-chroot package. I wonder what's the
effective benefit of this vs. a "normal" BIND setup without chroot. On
my Slackware servers, I have a rather Keep-It-Simple approach to all
things security, e. g. run no unneed services, open only needed ports
etc. but I don't run the extra mile (and haven't been bitten so far).

Any suggestions? (No flamefest please.)


Primary DNS server with BIND on a public machine running CentOS 7


I just installed CentOS 7 on a public server. I'd like to setup BIND as
a primary DNS server for a few domains.

Until now, all my public machines were running Slackware Linux, and
setting up BIND on a Slackware machine is relatively easy. In its out of
the box configuration, it has a bone-headed caching nameserver role,
which is quite easy to expand to a primary nameserver. Here's my
documentation. It's in French, but the *nix bits are universal.

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On my server running CentOS, I notice things are more complicated in the
default configuration.

Network configuration: desktop vs. laptop


I'm just migrating some stuff from Slackware Linux to CentOS, and I have
a question about the orthodox way of configuring a network connection.

On a desktop or workstation, I usually get rid of NetworkManager:

# systemctl stop NetworkManager
# yum remove NetworkManager

Then I edit the /etc/sysconfig/network-scripts/ifcfg-XXXXX file
corresponding to my network interface.

Dnsmasq and /etc/hosts


I just setup CentOS 7 on three boxes to fiddle with it.

1. amandine.sandbox.lan is a headless LAN server

2. bernadette.sandbox.lan is a client desktop

3. raymonde.sandbox.lan is another client desktop

I've setup Dnsmasq on amandine.sandbox.lan.

How do I default to "Folder View" in my custom KDE user profile?


I'm currently busy tweaking KDE 4.14 on CentOS 7 to my needs. I want to
use it as a base for an enterprise class desktop.

Trouble setting up HP Officejet Pro 8600 printer on CentOS 7 + KDE


I just installed a CentOS 7 + KDE desktop in my office's network. So
far, I'm quite happy with the results, though I have some trouble
getting the printer to work. All the other machines in my office
(server, desktops, workstation) are running Slackware64 14.1 or 14.2,
and they can all use the printer perfectly.

I installed hplip-gui and ran it.

CentOS 7 + KDE - default keyboard layout?


I'm currently fiddling with CentOS 7 and KDE 4.14, and I must say, I'm
pleasantly surprised. This is one of the cleanest implementations of KDE
I've ever seen, and with some tweaking (a lot, in fact) this can be
turned into a highly functional desktop with all the bling and bells and

But right now, I have some minor problems to solve. First things first.
My system is installed in French, with a swiss french keyboard
(fr_CH-latin1) as default.

Disable calendar notification in GNOME / CentOS 7 ?


Here's one of the problems adressed in a previous thread, but it got
somehow swept away in the heat of the discussion.

Since I'm using Thunderbird and not Evolution, I'd like to get rid of
the calendar notifications in GNOME's system menu.

Ideally, things should work like this:

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There's an extension called "Nothing To Do" which is supposed to do
exactly that, e. g.

Thunderbird vs. Evolution vs. OwnCloud


I'm currently using Thunderbird synced to OwnCloud on my main
workstation running Slackware64 14.1. I just installed CentOS 7 on my
Asus S300 laptop. It's running nicely, and I'm spending some time
getting acquainted with it.

I wonder if I should stick with Thunderbird or go with the default
Evolution application, since this seems to be better integrated into the
desktop, namely the calendar function.

On the other hand, it seems like you have to jump through burning loops
to connect Evolution to OwnCloud.

What are your experiences with these two clients and OwnCloud?

NetworkManager icon not showing


I just installed CentOS 7 on my Asus S300 laptop. Wireless was working
OK at first, but now for mysterious reasons the NetworkManager icon
seems to have disappeared from the notification area. When I click on
that area, there's only information showing about sound, brightness,
battery status and the connected user.

Which leaves me clueless. Any suggestions?

Niki Kovacs

CentOS 7 : keyboard shortcut for mouse gesture?


I have a CentOS 7 (GNOME) desktop installed as a VirtualBox guest on my
Slackware64 14.1 workstation, to fiddle with it.

Custom desktop menu entries: weird behavior with menu categories


For my client's desktops, I'm usually customizing the various Linux
desktops I'm installing. I'm using custom icon themes (Elementary),
custom system fonts (Droid Sans), and one of the things I also customize
are desktop menu entries.

Here's an example of what I do on a Slackware+Xfce-based desktop, so you
get the idea.

Duplicate *.desktop entries for GNOME in /usr/share/applications


Today I noticed something strange. There seem to be a series of
duplicate desktop menu entries in /usr/share/applications.

Example: gedit.desktop and org.gnome.gedit.desktop

Other example: nautilus.desktop and org.gnome.Nautilus.desktop

This is annoying, since I usually edit some custom menu entries for my
users. Now, if I edit both files for a single application, I end up with
duplicate menu entries.

Any suggestions?



Software RAID and GRUB on CentOS 7


When I perform a software RAID 1 or RAID 5 installation on a LAN server
with several hard disks, I wonder if GRUB already gets installed on each
individual MBR, or if I have to do that manually. On CentOS 5.x and 6.x,
this had to be done like this:

# grub
grub> device (hd0) /dev/sda
grub> device (hd1) /dev/sdb
grub> root (hd0,0)
grub> setup (hd0)
grub> root (hd1,0)
grub> setup (hd1)
grub> quit

I'd like my server to be able to boot a degraded software RAID after an
eventual hard disk failure.

Any suggestions?

Niki Kovacs

CentOS 6 + nux-dextop: GIMP vs. GIMP 2.8 ?


I just setup a CentOS 6 desktop with the nux-dextop repository activated.

When installing GIMP (yum install gimp), I get a gimp package as well as
a gimp28 package. I understand this is the Nux-Dextop GIMP 2.8 package.
Unfortunately this doesn't work so well with my system.

Minimum RAM requirement for CentOS 6.x graphic installer?


The title says it all. What's the minimum RAM requirement for the CentOS
6.x graphic installer? In our public libraries we have some old hardware
running CentOS 5, and I wonder if some of these machines can be upgraded
to CentOS 6. Unfortunately RHEL 5.x' nifty text mode installer got
seriously crippled with version 6.x.


Niki Kovacs

Status of RPMFusion repo for CentOS 5 and 6 ?


I have to maintain (and eventually beef up) desktop clients in public
libraries running CentOS 5 and 6. The hardware is still OK, though
sometimes really old, so the least evil will be to keep CentOS 5 on the
old machines until that version is EOL.

I've been using CentOS 5 as my main system somewhere between 2007 and
2009. At the time the RPMForge was my favorite third-party repository,
though I understand that project is dead. I'm looking for a clean and
viable solution to replace this. Here's what I intend to do.


Redefine ethX interface names in CentOS 5.11?


I have a LAN server running CentOS 5.11 with two NICs eth0 and eth1.

CentOS 7 + GUI as KVM guest: fix screen resolution


I'd like to run CentOS 7 in a KVM guest (host is my Slackware64 14.1
workstation). The main purpose of this installation will be to build
custom RPM packages. I've made a few tests, and everything works more or
less as expected.

Display boot menu with GRUB_TIMEOUT=0?


On my minimal installation of CentOS 7, here's what I have in

GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
video=1024x768 \

According to the official documentation, pressing any alphanumerical key
just after the BIOS screen will make the GRUB menu appear.

Unexpected behavior of 'yum group list' and 'yum group install'


I'm currently experimenting with Yum on a fresh CentOS 7 minimal
install, and I'm getting some puzzling results. Here's what I did.

1. Install CentOS 7 from the Minimal CD.

2. Install 'deltarpm' and update all packages.

3. Install the "Core" package group: 'yum group install "Core"'

4. Install the "Base" package group: 'yum group install "Base"'

5. As expected, 'yum group list hidden | less' shows this:

Installed Groups:

6. Now I remove manually all packages that were not present in the
initial installation.

Reduce existing CentOS 7 installation to "Minimal install" - services?


When I install a CentOS server/desktop/workstation, I usually start from
scratch with a barebone minimal installation, then add packages as needed.

Some machines (like dedicated servers in a datacenter) come
preconfigured by the hosting company, so I thought it wouldn't be a bad
idea to start stripping that stuff first.

Here's a little script I wrote, which essentially strips down any
CentOS-7 installation to a minimal core system:

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The script parses the 'minimal' package list and then just removes

RAID1 bootloader configuration on CentOS 6.x and 7


The CentOS wiki sports a page about setting up software RAID1 on CentOS
5.x. There's a section about making both members of the RAID1 bootable
by setting up GRUB on both disks.

Now I wonder how this should be done on CentOS 6.x and 7.

kmod-fglrx not available on CentOS 7?


The subject says it all. I'm currently busy installing a CentOS 7 based
desktop on a client's machine, an HP Compaq with an ATI video card.

# lspci | grep -i vga
01:05.0 VGA compatible controller: Advanced Micro Devices, Inc.
[AMD/ATI] RS780C [Radeon 3100]

I wanted to give the proprietary video driver a spin, so I configured
ELRepo, but curiously enough, there seems to be no kmod-fglrx driver

Why is that so?