Yenya's World

Wed, 04 Nov 2015

Fedora 23

The upgrade to F23 was flawless both on my workstation and on my laptop. So far the changes I noticed were:

To sum it up, pretty flawless upgrade. I will obviously wait for some time before upgrading my home dual-seat desktop, as I always do.

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Tue, 15 Sep 2015

Eternal Spring

This year we spent our holidays in the island of eternal spring. I have been to Madeira in 2010 at a conference, and I had only about two and half days to visit something outside the hotel. This time, we decided to spend two weeks there: one week in Funchal, and another one somewhere close to the Northern coast.

Pico Ruivo

We tried to ask travel agencies whether two-weeks trip with them is possible, but the reply was that it would be difficult. So we ended up booking the flight and accomodation for both weeks separately. Surprisingly enough, the price was about the same as with the travel agency.

Caldeirao Verde

We enjoyed the sea, gardens in Funchal, mountains, and of course levada walks. The weather was nice: it was about 19 °C and foggy weather in the mountains, while the temperature attacked unbearable values of 35 °C in Brno. I can highly recommend Madeira, I would say there is still at least another week worth of interesting places for us to see there.

Have a look at a short description (about 25 photos, in Czech), or a larger photo gallery (about 200 photos).

Speaking of photo galleries: I used Photoswipe for the above gallery. It turned out to be customizable enough for my needs. The only drawback is that it does not work well in Fennec (a mobile version of Firefox on Android).

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Mon, 14 Sep 2015

Service Bloat

I have (finally) upgraded my home workstation/server/router to Fedora 22. Newer Fedora releases have an anti-feature called "product": one cannot simply install "Fedora", the "Fedora Product", such as Fedora Workstation, should be selected first. For a system with X session (two X sessions, in my case), "Fedora Workstation" seems to be a natural choice. It is not: "Fedora Workstation" can be translated from Fedora Newspeak to an ordinary English as "Fedora GNOME 3". So this is a no-go.

A time ago, I came across a suggestion that "Fedora Server" is probably the closest thing to former "Fedora". So I upgraded my home box to "Fedora Server". Today, after a routine inspection of open ports on my home server, I discovered that something is listening on port 9090 on INADDR_ANY (and IN6ADDR_ANY as well). One fuser -n tcp, and I discovered that the listening process is called cockpit-ws.

Digging further into it, it seems that this is a web-based administrative interface (do you remember linuxconf, anyone?), probably another futile attempt to encapsulate the strength of all the configuration files to some useless web-based interface. Moreover, it cannot be uninstalled, as it depends on the fedora-release-server package. A side note: the cockpit-ws package contains font files, which is probably against Fedora Font Packaging Guidelines.

I wonder what happened to the "no unnecessary services should be enabled by default" philosophy. It seems that Cockpit is a blatant example of an unnecessary service, which is not only installed by default, but also enabled by default in Fedora Server 22. I recommend to run the following commands:

# systemctl stop cockpit.socket
# systemctl disable cockpit.socket

What other kinds of service-bloat did you find on your computers? Watch for newly opened ports after Fedora upgrades.

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Mon, 31 Aug 2015

Mission Completed

The project I started long, long time ago and which made a slow, but steady progress since then, has been finished today. Also, this month is a 10 years anniversary of this blog, which I have started in August 2005.

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Tue, 14 Jul 2015

I am looking for the best way how to publish my photos on the Web. So far I have ruled out putting my photos to some "cloud" service out of my control (Picasa, Flickr, Rajče). I want something which could generate a static tree of files (HTML/CSS/JPG/JS), which can then be published by any web hosting service, or even on my own server.

Some time ago I have tested Highslide.js, but this is more lightbox than a gallery, and it cannot adapt itself to the size of the screen.

I have looked at Darktable, which has its own "web gallery" export format, but surrounding Javascripts are not good enough to make it fit the screen. I have googled many other project, usually ruling them out solely based on their demo galleries.

What looks promising so far, is the thing named Photoswipe. There still are some problems, though:

So, my dear lazyweb: which gallery for static files do you use? I would like to have something with the following properties:

What would you recommend?

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Mon, 13 Jul 2015

Systemd Developer Attitude

Systemd. Some people love it, some people hate it. My own position is somewhere in between: I think many things they are trying to solve are real problems which need solutions, the system should "just work" for common use without the configuration, etc. But sometimes the overall attitude of the systemd developers is just plain wrong. The following bug report shows the problem pretty clearly: provide non standard time - issue #437

TL;DR: it can be summarized as follows:

There are several solutions to this problem which I would consider clean and fair:

The systemd maintainer's response was "we are not a vendor, we don't want a vendor pool", and "let's add a warning when somebody uses the defaults". I think using Google servers against the will of their owner is pretty rude, and having the defaults which need to be replaced, even though the possibility of having sane defaults exists, to be inconsiderate to their users.

In my opinion, the above clearly shows the attitude of systemd developers towards the rest of the world.

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Fri, 10 Jul 2015

My First CVE Number

After banging our collective heads against the wall while trying to discover why one Samba share works as we expect, while another one with the same configuration on the same server does not, I have finally admitted that the bug is not in our setup, but probably in Samba itself.

Interestingly enough, the expected behaviour was the share where it did not work, and the other one worked only by accident. The fact that it worked in one case turned out to be a potential minor security issue. So this is the first security issue I have discovered, which has its own CVE number: CVE-2015-3287 (details will be in Samba bug #11395 after it is declassifiled).

I appreciate the fast response of Samba developer Jeremy Allison: the first fix was available within 3.5 hours after the bug was reported.

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Tue, 09 Jun 2015

Laptop Upgrade, take 2

After thinking about upgrading my laptop in 2013, it is time for another try. My old ASUS F3E has flaky power connector, and sometimes fails to charge, which is quite annoying. So far my requirements are:

Of course, all the above criteria are met with exactly zero laptops currently available in the Czech Republic. So far I am considering the following less-than-optimal models:

So, my dear lazyweb, what would you recommend? Any other models? Any known problems with the abovementioned laptops? Thanks!

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Fri, 29 May 2015

Historic Bugs

After each Fedora release, the bugs reported to the release which is to be EOL'd, are being closed. I have looked at the notifications sent out after the Fedora 22 release, and most of my bugs-to-be-closed are waiting for the developers to do something about the bug. I wonder whether reporting bugs to Fedora bugzilla is still worth the effort. Anyway, the following reply to the bug closing notice made my day:

No! This bug is on the federal register of historic bugs! You can't close it now. Changing to fedora 22 (where, of course, it is still busted).

As you might guess this is in reply to the infamous "no way to control X server startup options" bug #451562 of GNOME Display Manager. There is nothing being done about the bug (reported in 2008 against Fedora 9), despite promises from 2009, that the bug is being worked on. Apparently GNOME developers are busy making their applications incompatible with other desktop environments instead.

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Thu, 28 May 2015

GNOME-Only Applications

Once upon a time, there was a windowing system called X. There were lots of applications for X written using various widget toolkits. In order to make the window operations unified across the whole desktop, regardless of the widget toolkit used by a particular application, the special application, called "window manager" provided window title bars and borders. Applications could inform the window manager about their particular needs (for example, their minimum required window size, etc.) using an open protocol called ICCCM. Not anymore.

Nowadays, GNOME developers decided that the only way to use their system and their applications is to have the complete desktop including all running apps GNOME-based. Being able to run GNOME apps under other desktop environments and vice versa is sooo last century way of desktop computing. From now on, all GNOME applications inform the window manager using ICCCM, that their windows are not to be touched by the WM. These windows then do not have window borders for resizing, raising/lowering/etc., they have their own title bar and maximize/minimize/close buttons different to the rest of the desktop, etc.

OK, after ditching GNOME desktop environment when GNOME 3.0 came out, it is time to ditch also the GNOME applications, as they are clearly not intended to run under the standard desktop environment. So far I have replaced the following applications:

evince with Okular
This means installing lots of KDE libraries, but on the other hand Okular does not take over the screen on startup (unfixed since at least 2008), it can zoom to the arbitrary size (CLOSED WONTFIX, really?), when I run "okular somefile.pdf" twice, I get two windows as expected, etc.
file roller with thunar-archive-plugin
Not that I use the GUI file manager often, but still.
eog and gthumb with (undecided yet)
I am still not sure about the replacement - so far I am testing ristretto, geeqie and some others.

There is a nice list of recommended applications for XFCE, which are written in GTK, but positively GNOME-free. Which image viewer and PDF viewer do you use, my dear lazyweb?

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Mon, 23 Mar 2015

Backward Compatibility

One of the alleged advantages of certain family of operating systems from Redmond is backward compatibility. They say they support interfaces and applications back to the DOS era, and they sometimes even use this feature as an excuse for some doubtful technical choices they made. Yesterday I have discovered that it is not as good as they often say.

I wanted to install The Neverhood, an old 1996 adventure game. The result was the perfectly working game under WINE and Linux, and partly-working game under Windows 8.1: the gameplay was OK, but the in-game video sequences and their sound were too sluggish, as if it required 5 to 10 times more powerful hardware. According to the discussion forum posts about this topic, it is a common problem in newer versions of Windows. The recommended solution is to run the game under ScummVM, which is a rewrite of many ancient game engines.

Remember this the next time you hear an exaggerated statement about the backward compatibility of Windows.

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Thu, 19 Mar 2015

Libvirt Dependencies

Welcome to Yenya's rant about software "features". Today we will have look at libvirt in Fedora and its dependencies. But firstly let me show you a funny picture:


Anyway. I teach a seminar on Linux administration, where one of the tasks is to compile and use one's own kernel. The task for the following week is to create a virtual machine. One of my students had an interesting problem with the second task - virsh refused to start his KVM-based virtual machine with the "command timeout" message.

Digging into the issue, we discovered that it works with the distribution kernel, but not with his custom kernel. Then we found that virsh tries to do a RPC call over D-Bus, which then times out, because the D-Bus object in question was not present. This object is supposed to be provided by a daemon called systemd-machined, which describes itself with the following headline:

This is a tiny daemon that tracks locally running Virtual Machines and Containers in various ways.

This is in fact an understatement, with the real situation being that this daemon is a core part of the virtualization subsystem, and it is not even possible to start a libvirt-managed guest without it. We have tried to start the daemon from the command line, but it immediately exited without a meaningful message anywhere. The only message in the syslogjournal was that systemd-machined failed to start when the system was booted.

Long story short, my lucky guess was that systemd-machined could have something to do also with containers, and it might have needed a container support in the kernel. After enabling about five namespaces-related kernel config options and booting a recompiled kernel, we were able to start systemd-machined, and only then we managed to start the VM using virsh.

This spaghetti-structured unstraceable mess of interconnected daemons communicating over D-Bus and providing no meaningful error messages, which is masqueraded under a collective name "systemd", makes me sick quite often.

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Tue, 30 Dec 2014

PF 2015

I wish a nice year 2015 to all readers of this blog.

PF 2015

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Sat, 20 Dec 2014

HDMI Sound

Another problem related to getting a new mainboard was sound. The mainboard has an on-board Intel GPU, which I use for the first seat. Unlike my previous graphics card for the Seat0, it is connected by HDMI port to my monitor. So I have decided to give sound over HDMI a try.

The problem was that it did not work: using pavucontrol, I have verified that sound is routed correctly to the HDMI interface, but the interface said that the output is disconnected. And I did not know how to "connect" it, because physically it has obviously been connected.

After some hours of searching I have found the following solution:

$ pactl list cards
Card #1
	Name: alsa_card.pci-0000_00_03.0
	Driver: module-alsa-card.c
		output:hdmi-stereo: Digital Stereo (HDMI) Output (sinks: 1, sources: 0, priority: 5400, available: yes)
		output:hdmi-surround: Digital Surround 5.1 (HDMI) Output (sinks: 1, sources: 0, priority: 300, available: yes)
		output:hdmi-stereo-extra1: Digital Stereo (HDMI 2) Output (sinks: 1, sources: 0, priority: 5200, available: yes)
		output:hdmi-surround-extra1: Digital Surround 5.1 (HDMI 2) Output (sinks: 1, sources: 0, priority: 100, available: yes)
		output:hdmi-stereo-extra2: Digital Stereo (HDMI 3) Output (sinks: 1, sources: 0, priority: 5200, available: yes)
		off: Off (sinks: 0, sources: 0, priority: 0, available: yes)
	Active Profile: output:hdmi-stereo
		hdmi-output-0: HDMI / DisplayPort (priority: 5900, latency
offset: 0 usec, not available)
				device.icon_name = "video-display"
			Part of profile(s): output:hdmi-stereo, output:hdmi-surround
		hdmi-output-1: HDMI / DisplayPort 2 (priority: 5800, latency
offset: 0 usec, not available)
				device.icon_name = "video-display"
			Part of profile(s): output:hdmi-stereo-extra1, output:hdmi-surround-extra1
		hdmi-output-2: HDMI / DisplayPort 3 (priority: 5700, latency
offset: 0 usec, available)
				device.icon_name = "video-display" = "PLE2607WS"
			Part of profile(s): output:hdmi-stereo-extra2
$ pactl set-card-profile 1 output:hdmi-stereo-extra2

Apparently PulseAudio knows that the hdmi-stereo-extra2 is the only connected output, but remains set up to hdmi-stereo instead. Now that is not very user-friendly, plug&play, etc.

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Fri, 19 Dec 2014

Multiseat LightDM

After getting a new mainboard, I have upgraded my home computer to Fedora 20, and made my multiseat setup use the udev/logind/loginctl seat tags. About a month ago I have discovered that the seat numbers are not correctly assigned to sessions by xdm(8), so I started to look for solutions. Of course, that piece of crap called gdm was not even been considered for obvious reasons. Apparently the solution does exist, and suprisingly enough, it is really nice: it is called LightDM.

LightDM is the display manager. It has cleanly separated the display manager part (starting up the X servers, listening on XDMCP, etc.), and the user interface part (chooser). The later can be selected from various options - e.g. a KDE/Qt compatible one, and a GTK+ compatible one. The configuration is pretty straigthforward, and it does not try to hide anything from the user, unlike the above mentioned piece of crap.

The multiseat setup in LightDM is pretty straightforward: in /etc/ligthdm/lightdm.conf I have to add the following:

xserver-command=X -layout Primary -isolateDevice PCI:0:2:0 -seat seat0 vt7

xserver-command=X -layout Secondary -isolateDevice PCI:1:0:0 -seat seat1
-sharevts vt7

In the udev tags, I had to tag the following device as belonging to Seat1 (using loginctl(8)):

And that's it! The only (minor) nitpick is, that the GTK+ greeter does not remember the last logged-in user per seat, so it preselects the last logged in user on both seats by default. But we usually log in only after the reboot, so it is not a big problem.

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