Systemd

Immutable Atomic Linux Distirbutions

Of late, I’ve been hearing a lot of (good) things about Immutable Linux Distributions, from friends, colleagues and mentors. It has been something on my plate for some time, to explore. But given the nature of the subject, it has been delayed for a while. Reasons are simple; I can only really judge this product if I use it for some time; and it has to be on my primary daily driver machine.

With KDE 6.5.0, PowerDevil has broken forced its own set of suspend/hibernate inhibitors onto logind. And to my knowledge, there’s no way to disable them.

As a user, I’d prefer to set lid action as Do nothing and really expect KDE/PowerDevil to do nothing in that regard. But with KDE 6.5.0 PowerDevil forces those inhibitors whatsoever.

❯ systemd-inhibit  --list
WHO            UID  USER PID   COMM            WHAT                                                                       WHY                                                        >
ModemManager   0    root 3541  ModemManager    sleep                                                                      ModemManager needs to reset devices                        >
NetworkManager 0    root 3453  NetworkManager  sleep                                                                      NetworkManager needs to turn off networks                  >
UPower         0    root 4342  upowerd         sleep                                                                      Pause device polling                                       >
PowerDevil     1000 rrs  82735 org_kde_powerde handle-power-key:handle-suspend-key:handle-hibernate-key:handle-lid-switch KDE handles power events                                   >
Screen Locker  1000 rrs  4844  kwin_wayland    sleep                                                                      Ensuring that the screen gets locked before going to sleep >

5 inhibitors listed.

This essentially prohibits logind to act on the lid actions. And instead forces the user to depend on nothing else and other than PowerDevil. This assumes the wishful thought that PowerDevil is Solid.

Finally, TIL, what can all be the reason for systemd services to hang indefinitely. The internet is flooded with numerous reports on this topic but no clear answers. So no more uselessly marked workarounds like: systemctl daemon-reload and systemctl-daemon-reexec for this scenario.

The scene would be something along the lines of:

rrs         6467  0.0  0.0  23088 15852 pts/1    Ss   12:53   0:00  |   |   \_ /bin/bash
rrs        11512  0.0  0.0  14876  4608 pts/1    S+   13:18   0:00  |   |   |   \_ systemctl restart snapper-timeline.timer
rrs        11513  0.0  0.0  14984  3076 pts/1    S+   13:18   0:00  |   |   |       \_ /bin/systemd-tty-ask-password-agent --watch
rrs        11514  0.0  0.0 234756  6752 pts/1    Sl+  13:18   0:00  |   |   |       \_ /usr/bin/pkttyagent --notify-fd 5 --fallback

The snapper-timeline service is important to me and it not running for months is a complete failure. Disappointingly, commands like systemctl --failed do not report of this oddity. The overall system status is reported to be fine, which is completely incorrect.

KDE Impressions

These days, I often hear a lot about Wayland. And how much of effort is being put into it; not just by the Embedded world but also the usual Desktop systems, namely KDE and GNOME.

In recent past, I switched back to KDE and have been (very) happy about the switch. Even though the KDE 4 (and initial KDE 5) debacle had burnt many, coming back to a usable KDE desktop is always a delight. It makes me feel home with the elegance, while at the same time the flexibility, it provides. It feels so nice to draft this blog article from Kwrite + VI Input Mode

Linux and ARM

With more ARM based devices in the market, and with them getting more powerful every day, it is more common to see more of ARM images for your favorite Linux distribution. Of them, Debian has become the default choice for individuals and companies to base their work on. It must have to do with Debian’s long history of trying to support many more architectures than the rest of the distributions. Debian also tends to have a much wider user/developer mindshare even though it does not have a direct backing from any of the big Linux distribution companies.

For Debian Jessie, the multipath support relied on sysvinit scripts. So, if you were using systemd, the level of testing would have been minimal.

At DebConf15, I got to meet many people whom I’d worked with, over emails, over the years. With every person, my ask was to use the SAN Storage stack in a test environement, and report bugs early. Not after the next release. This applies also to the usual downstream distribution projects.

For some time, I have been wanting to read more on Linux Cgroups to explore possibilities of using it to control Ill behaving applications. At this time, while I’m stuck in travel, it has given me some time to look into it.

In our Free Software world, most of the things are do-o-cracy, i.e. when your use case is not the common one, it is typically you who has to explore possible solutions. It could be Bugs , Feature Requests or as is in my case, performance issues. But that is not to assume that we do not have better quality software in Free Software world. Infact, in my opinion, some of the tools available are far much more better than the competition in terms of features, and to add a sweetener (or nutritional facts) to it is the fact that Free Software liberates the user.

I am please to announce the release of Laptop Mode Tools, version 1.68.

This release is mainly focused on integration with the newer init system, systemd. Without the help from the awesome Debian systemd maintainers, this would not have been possible. Thank you folks.

While the focus now is on systemd, LMT will still support the older SysV Init.

With this new release, there are some new files: laptop-mode.service, laptop- mode.timer and lmt-poll.service. All the files should be documented well enough for users. lmt-poll.service is the equivalent of the module battery- level-polling , should you need it.

A couple of us DDs met here on the weekend. It is always a fun time, being part of these meetings. We talked briefly about the status of Cross Compilation in Debian, on the tools that simplify the process.

Next we touched upon licensing, discussing the benefits of particular licenses (BSD, Apache, GPL) from the point of view of the consumer. The consumer being an individual just wanting to use/improve software, to a consumer who’s building a (free / non-free) product on top of it. I think the overall conclusion was that there are 2 major licenses at a high level: Ones those allow you take the code and not give back, and the others which allow you to take code only if you are ready to share the enhancements back and forward.

I recently switched to a ThinkPad W530 laptop. It is a fairly recent machine with the following hardware config:

• Intel(R) Core(TM) i7-3720QM CPU @ 2.60GHz
• 8 GiB RAM
• nVIDIA Optimus
• Samsung SSD Drive

On the software front, I decided to take my chances. Hence: