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Archive for 2019

Highlights of YaST Development Sprint 91

December 18th, 2019 by

The last two weeks of the year, and also the first one of the new year, are vacation season in many parts of the world and YaSTland is not an exception. But before we enter hibernation mode, let’s take a look to the most important features and bugfixes we implemented in the last sprint of 2019. That includes:

  • bringing back to life some sections of the Software Manager,
  • implementing system upgrade with the new SLE media types,
  • making the installation in Raspberry Pi and IBM Z System even better,
  • improving usability of encryption,
  • reducing the footprint of the Snapper plugin for ZYpp,
  • as always, many other small improvements and fixes.

Restored Some Package Views: Recommended, Suggested, etc.

Let’s start with a redemption story. Some time ago we implemented feature fate#326485 which requested dropping the “Package Groups” view from the package manager UI. That was quite an easy task.

However, a few weeks later we got a bug report that the lists of recommended, suggested, etc… packages couldn’t be displayed anymore. It turned out that, in the Qt package manager front-end, the removed “Package Groups” view not only used to display the static group data from the packages but it also contained some special computed package lists like orphaned, suggested or recommended packages. So these lists were lost as a collateral damage of removing the “Package Groups” view.

The ncurses package manager was not affected by the same problem because, in that front-end, those views are grouped in a separate “Package Classification” section. So the task for this sprint was to somehow revive the lists in Qt and make them again available to the users.

We partly reverted the Package Groups removal and restored displaying those special package groups. To make it consistent we also use the “Package Classification” name for the view, like in the ncurses package manager.

The new Package Classification view in Qt

On the other hand, the ncurses front-end was missing some lists like the “Multiversion Packages” and “All Packages”. To take consistency another step further, we added these missing lists and did some small cleanup and fixes so now both the Qt and the ncurses package managers should offer the same functionality and should look similar.

The revamped Package Classification view in ncurses

User-friendly Encryption Device Names

And talking about bug reports that trigger some usability revamp, some users had pointed that, when the system is booting and prompts for the password of an encrypted device, it’s not always that easy to identify which exact device it is referring to:

Booting password prompt before the change

The root of the problem is that when YaST creates an encryption device (during the installation by means of the storage proposal, or manually with the Expert Partitioner), the device mapper name for the new encrypted device is generated from the udev id of the underlying device (e.g., cr_ccw-0XAF5E-part2).

We decided to improve the encryption naming generation in YaST for Tumbleweed and future releases of Leap and SLE. From now on, the name will be based on the mount point of the device. For example, if an encrypted device is going to be mounted at root, its device mapper name would be cr_root. In general, when the encrypted device is mounted, the device mapper name would be cr_mount_point (e.g., cr_home_linux for an encrypted device mounted at /home/linux).

Booting password prompt after the change

Note that udev-based names might still be used for some scenarios. For example, when the device is not mounted or for an indirectly used encrypted device (e.g., an encrypted LVM Physical Volume).

And related to the identification of encryption devices, we have also added more information about the device when the encryption devices are activated during the installation process. Providing the password for the correct device was very difficult because the user needed to know the UUID of the encryption device. Now on, the activation popup also informs about the kernel name of the underlying device, making much easier to identify it.

New password prompt during installation

Because names matter… which leads us to the next topic.

How does it Feel to Run a Mainframe?

As you may know, (open)SUSE runs in a vast range of hardware, including powerful mainframes like the IBM Z family. One of the strengths of our beloved distributions is that, despite the differences in hardware and scope, the installation and usage experience is very similar in all the supported systems.

Consistency and ease of use are good, but when you drive a luxury car you want to see the brand’s badge on top of the hood. So in future versions of the installer, the model of the machine will be displayed when installing in an IBM Z system. See the right-top corner of the following screenshot.

IBM Z Model in the installer

The text-based installer also has been modified to include the same banner in a similar place.

IBM Z Model in the text-mode installer

But in the same way that (open)SUSE enables you to install and use Linux in a mainframe “just like in any other computer”, we also target to do the same in the other extreme of the hardware spectrum.

Better Support for Raspberry Pi in the Partitioning Proposal

One year ago we announced that openSUSE Leap 15.1 and SLE-15-SP1 would be the first Linux distributions that could be installed in Raspberry Pi devices following the standard installation procedure, instead of deploying a Raspberry-specific pre-built image. The only prerequisite was the existence in the target SD card (or disk) of a partition containing the Raspberry Pi boot code.

But we are now able to go one step further for SLE-15-SP2 (and Leap 15.2). Thanks to the technologies included in those upcoming releases, (open)SUSE will not longer need a separate partition with the boot code in all cases. Now the installer can make a reasonable installation proposal in all situations, even if the target storage device doesn’t contain a booting partition in advance. See, for example, what the installer suggests by default for installing a fully standard SLE-15-SP2 Beta1 in a 32 GiB SD card that contained initially a GPT partition table (tip: GPT partition tables cannot be used to boot in a Raspberry Pi device… and the installer knows it).

Installer proposal for a Raspberry Pi

With that, the installation of the standard SLE-15-SP2 Beta1 (the aarch64 version, of course) in a Raspberry Pi 3 or 4 is as easy as “next”, “next”, “next”… with the only exception of a couple of packages that must be manually selected for installation (raspberrypi-* and u-boot-rpi3). Hopefully, future beta images of both SLE and openSUSE Leap 15.2 will select those packages automatically when installing in a Pi, which will make the (open)SUSE experience in those devices basically identical to any other computer.

SLE Upgrade with the New Media Types

And talking about the standard installation images of the upcoming SLE-15-SP2, we explained in our previous blog post that those versions of SUSE Linux Enterprise (SLE) and all its associated products will be distributed in two new kinds of media – Full and Online. The Full Media contains many repositories and the system can be installed without network connectivity. The Online Media is similar to the openSUSE’s net installer, it contains no repository and it must download everything from the network. The big difference with openSUSE is that SLE systems need to be registered in order to have access to remote repositories.

But apart from installation, those two new media types can also be used to upgrade an existing system… at least after all the improvements implemented during the latest sprint.

In the case of the Online Media, if the system is registered the upgrade process will switch all repositories to point to their corresponding versions at the SUSE Customer Center (SCC) and will get the new software from there. If the system is not registered, the upgrade process is cancelled and the user is advised to either register the system or use the Full Media.

The Full Media can be used to upgrade any system, registered or not, but the process is different in each case. For a non-registered system, the repositories will be switched to the ones included in the media and the system will be upgraded from there. For registered systems the process is the same that with the Online Media, so the software will be fetched from the remote repositories at the SUSE Customer Center.

Last but not least, we also made sure the process with both medias works with an AutoYaST upgrade (yes, you can also use AutoYaST to perform an unattended upgrade, in addition to the better known unattended installation). For a registered system, we simplified the procedure as much as possible and it only needs access to SCC and an empty AutoYaST profile. For non-registered systems it is a little bit more complex because the profile must specify which repositories from the media should be used for the upgrade. But other than that, the process works quite smooth.

And, of course, we used the opportunity to improve the unit test coverage of the code and to improve the documentation, including the profiles we used for testing.

The Snapper Plugin for ZYpp Becomes More Compact and Future-proof

Snapper lets you make filesystem snapshots. It has a companion, snapper-zypp-plugin, a plugin for ZYpp that makes snapshots automatically during commits. See the “zypp” descriptions in this listing:


# snapper list

  # | Type   |Pre # | Date                     | User | Used Space | Cleanup  | Description  | Userdata     
----+--------+------+--------------------------+------+------------+----------+--------------+-------------
  0 | single |      |                          | root |            |          | current      |              
[...]
824 | pre    |      | Tue Dec 17 10:00:27 2019 | root |  16.00 KiB | number   | zypp(zypper) | important=no
826 | post   |  824 | Tue Dec 17 10:02:19 2019 | root |  16.00 KiB | number   |              | important=no
827 | single |      | Tue Dec 17 11:00:01 2019 | root |  16.00 KiB | timeline | timeline     |             
828 | single |      | Tue Dec 17 11:00:01 2019 | root |  16.00 KiB | timeline | timeline     |             

To make our enterprise products supportable for a looong time, we have rewritten this plugin to C++, starting with snapper-0.8.7. (The original Python implementation is not dead, it is resting in old Git commits.)

As a result, Python regular expressions are no longer supported in the /etc/snapper/zypp.conf file. POSIX extended regular expressions work instead, which should work sufficiently well for the purpose of package name matching. Shell patterns continue working unchanged.

Happy new year!

During the following three weeks, the YaST team will interrupt the usual sprint-based development pace. That also means, almost for sure, that we will not publish any blog post about the development of YaST until mid January of 2020. So we want to take this opportunity to wish you a happy new year full of joy and Free Software.

See you soon and make sure to start the year with a lot of fun!

openSUSE on reproducible builds summit

December 13th, 2019 by

As in the past 3 years, I joined the r-b summit where many people interested in reproducible builds met.

There were several participants from companies, including Microsoft, Huawei and Google.
Also some researchers from universities that work on tools like DetTrace, tuf and in-toto.
But the majority still came from various open-source projects – with Fedora/RedHat being notably absent.

We had many good discussion rounds, one of which spawned my writeup on the goal of reproducible builds

Another session was about our wish to design a nice interface, where people can easily find the reproducibility status of a package in various distributions. I might code a Proof-of-Concept of that in the next weeks (when I have time).
I also got some help with java patches in openSUSE and made several nice upstream reproducibility fixes – showing some others how easy that can be.

This whole event also was good team-building, getting to know each other better. This will allow us to better collaborate in the Future.

Later there will be a larger report compiled by others.

Highlights of YaST Development Sprint 90

December 5th, 2019 by

As usual, during this sprint we have been working on a wide range of topics. The release of the next (open)SUSE versions is approaching and we need to pay attention to important changes like the new installation media or the /usr/etc and /etc split.

Although we have been working on more stuff, we would like to highlight these topics:

  • Support for the new SLE installation media.
  • Proper handling of shadow suite settings.
  • Mount points handling improvements.
  • Help others to keep the Live Installation working.
  • Proper configuration of console fonts.
  • Better calculation of minimum and maximum sizes while resizing ext2/3/4 filesystems.
  • Small fixes in the network module.

The New Online and Full SLE Installation Media

The upcoming Service Pack 2 of SUSE Linux Enterprise products will be released on two media types: Online and Full.

On the one hand, the Online medium does not contain any repository at all. They will be added from a registration server (SCC/SMT/RMT) after registering the selected base product. The Online medium is very small and contains only the files needed for booting the system and running the installer. On the other hand, the Full medium includes several repositories containing base products and several add-ons, which can help to save some bandwidth.

Obviously, as the installer is the same for both media types, we need to adapt it to make it work properly in all scenarios. This is an interesting challenge because the code is located in many YaST packages and at different places. Keep also in mind that the same installer needs to also work with the openSUSE Leap 15.2 product. That makes another set of scenarios which we need to support (or at least not to break).

The basic support is already there and we are now fine-tuning the details and corner cases, improving the user experience and so on.

Proper Handling of Shadow Suite Settings

A few weeks ago, we anticipated that (open)SUSE would split system’s configuration between /usr/etc and /etc directories. The former will contain vendor settings and the latter will define host-specific settings.

One of the first packages to be changed was shadow, which stores now its default configuration in /usr/etc/login.defs. The problem is that YaST was not adapted in time and it was still trying to read settings only from /etc/login.defs

During this sprint, we took the opportunity to fix this behavior and, what is more, to define a strategy to adapt the handling of other files in the future. In this case, YaST will take into account the settings from /usr/etc directory and it will write its changes to a dedicated /etc/login.defs.d/70-yast.conf file.

Missing Console Font Settings

The YaST team got a nice present this year (long before Christmas) thanks to Joaquín, who made an awesome contribution to the YaST project by refactoring the keyboard management module. Thanks a lot, Joaquín!

We owe all of you a blog entry explaining the details but, for the time being, let’s say that now the module plays nicely with systemd.

After merging those changes, our QA team detected that the console font settings were not being applied correctly. Did you ever think about the importance of having the right font in the console? The problem was that the SCR agent responsible for writing the configuration file for the virtual consoles was removed. Fortunately, bringing back the deleted agent was enough to fix the problem, so your console will work fine again.

Helping the Live Installation to Survive

Years ago, the YaST Team stopped supporting installation from the openSUSE live versions due to maintainability reasons. That has not stopped others from trying to keep the possibility open. Instead of fixing the old LiveInstallation mode of the installer, they have been adapting the live versions of openSUSE to include the regular installer and to be able to work with it.

Sometimes that reveals hidden bugs in the installer that nobody had noticed because they do not really affect the supported standard installation procedures. In this case, YaST was not always marking for installation in the target system all the packages needed by the storage stack. For example, the user could have decided to use Btrfs and still the installer would not automatically select to install the corresponding btrfsprogs package.

It happened because YaST was checking which packages were already installed and skipping them. That check makes sense when YaST is running in an already installed system and is harmless when performed in the standard installation media. But it was tricky in the live media. Now the check is skipped where it does not make sense and the live installation works reasonably well again.

A More Robust YaST Bootloader

In order to perform any operation, the bootloader module of YaST first needs to inspect the disk layout of the system to determine which devices allocate the more relevant mount points like /boot or the root filesystem. The usage of Btrfs, with all its exclusive features like subvolumes and snapshots, has expanded the possibilities about how a Linux system can look in that regard. Sometimes, that meant YaST Bootloader was not able to clearly identify the root file system and it just crashed.

"Missing '/' mount point" error

Fortunately, those scenarios are reduced now to the very minimum thanks to all the adaptations and fixes introduced during this sprint regarding mount points detection. But there is still a possibility in extreme cases like unfinished rollback procedures or very unusual subvolumes organization.

So, in addition to the mentioned improvements in yast2-storage-ng, we have also instructed yast2-bootloader to better deal with those unusual Btrfs scenarios, so it will find its way to the root file system, even if it’s tricky. That means the “missing ‘/’ mount point” errors should be gone for good.

But in case we overlooked something and there is still an open door to reach the same situation again in the future, we also have improved YaST to display an explanation and quit instead of crashing. Although we have done our best to ensure this blog entry will be the only chance for our users to see this new error pop-up.

YaST2 Bootloader: root file sytem not found

Improving the Detection of Mount Points

As mentioned above, improving the detection of mount points helped to prevent some problems that were affecting yast2-bootloader. However, that is not the only module that benefits from such changes.

When you run some clients like the Expert Partitioner, they automatically use the libstorage-ng library to discover all your storage devices. During that phase, libstorage-ng tries to find the mount points for all the file systems by inspecting /etc/fstab and /proc/mounts files. Normally, a file system is mounted only once, either at boot time or manually by the user. For the first case, both files /etc/fstab and /proc/mounts would contain an entry for the file system, for example:

$ cat /etc/fstab
/dev/sda1  /  ext4  defaults  0  0

$ cat /proc/mounts
/dev/sda1 / ext4 rw,relatime 0 0

In the example above, libstorage-ng associates the / mount point to the file system which is placed on the partition /dev/sda1. But, what happens when the user bind-mounts a directory? In such a situation, /proc/mounts would contain two entries for the same device:

$ mound /tmp/foo /mnt -o bind
$ cat /proc/mounts
/dev/sda1 / ext4 rw,relatime 0 0
/dev/sda1 /mnt ext4 rw,relatime 0 0

In the Expert Partitioner, that file system will appear as mounted at /mnt instead of /. So it will look like if your system did not have the root file system after all!

This issue was solved by improving the heuristic for associating mount points to the devices. Now, the /etc/fstab mount point is assigned to the device if that mount point also appears in the /proc/mounts file. That means, if a device is included in the /etc/fstab and the device is still mounted at that location, the /etc/fstab mount point takes precedence.

As a bonus, and also related to mount points handling, now the Expert Partitioner is able to detect the situation where, after performing a snapshot-based rollback, the system has not been rebooted. As a result, it will display a nice and informative message to the user.

System not rebooted after snapshot rollback

Improved Calculation of Minimum and Maximum Sizes for ext2/3/4

If you want to resize a filesystem using YaST, it needs to find out the minimum and maximum sizes for the given filesystem. Until now, the estimation for ext2/3/4 was based on the statvfs system call and it did not work well at all.

Recently, we have improved YaST to use the value reported by resize2fs as the minimum size which is more precise. Additionally, YaST checks now the block size and whether the 64bit feature is on to calculate the maximum size.

Polishing the Network Module

As part of our recent network module refactorization, we have improved the workflow of wireless devices configuration, among other UI changes. Usually, these changes are controversial and, as a consequence, we received a few bug reports about some missing steps that are actually not needed anymore. However, checking those bugs allowed us to find some small UI glitches, like a problem with the Authentication Mode widget.

Moreover, we have used this sprint to drop the support for some deprecated device types, like Token Ring or FDDI. Below you can see how bad the device type selection looks now. But fear not! We are aware and we will give it some love during the next sprint.

Network Device Type Selection

Conclusions

The last sprint of the year is already in progress. This time, we are still polishing our storage and network stacks, improving the migration procedure, and fixing several miscelaneous issues. We will give you all the details in two weeks through our next sprint report. Until then, have a lot of fun!

Highlights of YaST Development Sprints 88 and 89

November 22nd, 2019 by

A More User Friendly Role Selector Dialog

Step by step, we continue improving the user experience making use of the newly added widgets to libyui. This sprint was the turn to update the role selection dialog to use the new item selector introduced during the sprint 87. Apart from looking better as it can be seen in the screenshots below, there are two immediate improvements:

  • the vertical scroll, when present, is respected after selecting a role (instead of “jumping to the beginning”), and
  • the selected role (if any) will be visible when arriving at the dialog even when the list is quite long or the available space too short.
Before After

What is more, updating the dialog was also useful for us to realize about some needed improvements for the widget itself, mentioned in the next section. Quite a productive change 🙂

When one Bit is not Enough: The CustomStatusItemSelector

A few weeks ago, we wrote about the new ItemSelector widget that is finding its way into YaST user interfaces. It turned out that just a simple on/off status is not enough in some cases, so we had to extend that concept. For example, software modules may have dependencies, and we want to show the difference between one that was explicitly selected by the user and one that was auto-selected because some other software module requires it.

This kind of shook the foundations of the underlying classes; all of a sudden a bit is no longer just a bit, but it needs to be broken down into even smaller pieces. Well, we cheated; we now use integer values instead. Most of the class hierarchy still only uses 0 and 1, but the new YCustomStatusItemSelector also supports using higher numbers for application-defined purposes.

For each possible status value, the application defines the name of the icon to be displayed (for graphical UIs like the Qt UI), the text equivalent (for text mode / the NCurses UI), and an optional nextStatus which tells the widget what status to cycle to when the user changes the status of an item with a mouse click or with the keyboard. A value of -1 lets the application handle this.

So this is not a one-trick-pony that is useful only for that one use case (the software modules), but a generic tool that might find good uses in other places all over YaST as well.

Usage examples: C++, Ruby.

Snapper and Machine-readable Output

Most likely you already know snapper, a great tool to work with your filesystem snapshots. Some third-party scripts and tools (e.g., YaST) use the snapper CLI to get some information, but generally, snapper generates an output intended to be human-readable. Sometimes that could cause some troubles in scripts checking the snapper output. Now on, snapper also offers CLI options to generate its output in a machine-readable format, i.e., CSV and JSON. Please, check this post for more information about those new options.

Fix Boot Problems with Remote Encrypted Devices

Since we adopted systemd, the management during system boot of encrypted devices on top of network-based devices like iSCSI or FCoE disks has been less than optimal. But now we are happy to announce that we have put all the pieces together to make the experience as smooth as possible.

One of the main responsibilities of systemd is sorting the actions performed during boot and setting the dependencies between them. For example, if there are encrypted devices, systemd will first ask you for the password and activate the devices to afterwards mount the file system contained in those encrypted devices. Systemd should be able to distinguish when an encrypted device is based on a network-based storage device and, thus, can only be initialized after the network is up. In some cases that detection failed (for example network block device based mounts, such as iSCSI and FCoE disks) and systemd got stuck before initializing the network waiting for the device to be available.

Recently, SLE and openSUSE Leap has incorporated support for specifying the _netdev option in the /etc/crypttab file. With such option, systemd will recognize the encrypted device as network-based and will only try to activate it after setting up the network. That’s analogous to the corresponding _netdev option in /etc/fstab that has been already there for quite some time and that can be used to defer when a device is mounted. For it to work properly, the _netdev option must be present in all the relevant entries of both crypttab and fstab.

And that’s exactly what YaST will do now in openSUSE Tumbleweed and upcoming releases of both SLE and openSUSE Leap. From now on, the _netdev option will be added fstab for all mount points depending (directly or indirectly) on the network. In addition, that option (and also the noauto and nofail ones) will be propagated from fstab to all the corresponding crypttab entries.

This should mark the end of a dark age of encrypted iSCSI and FCoE devices timing out during boot.

AutoYaST Support for Random and Pervasive Encryption

Back in October, we announced that YaST got support for new encryption methods like random or pervasive encryption. At that time, AutoYaST was out of scope because we wanted to have a stable (and tested) API first. Fortunately, the time has come and now AutoYaST supports these encryption mechanisms.

Starting in autoyast2 4.2.17, you can specify the encryption method using a crypt_method element, as shown in the example below. Possible values are luks1 (regular LUKS1 encryption), pervasive_luks2 (pervasive volume encryption), protected_swap (encryption with volatile protected key), secure_swap (encryption with volatile secure key) and random_swap (encryption with volatile random key).

    <drive>
     <type config:type="symbol">CT_DISK</type>
     <use>all</use>
     <partitions config:type="list">
      <partition>
       <size>20G</size>
       <mount>/</mount>
       <filesystem config:type="symbol">ext4</filesystem>
       <crypt_method config:type="symbol">luks1</crypt_method> <!-- default method if crypt_key is defined -->
       <crypt_key>S3CR3T</crypt_key>
      </partition>
      <partition>
       <size>1G</size>
       <mount>swap</mount>
       <crypt_method config:type="symbol">random_swap</crypt_method> <!-- set encryption method -->
      </partition>
     </partitions>
    </drive>

As we want AutoYaST to be as user-friendly as possible, it will try to help you if you do some mistake setting the encryption configuration as when in the screenshot below.

Finally, the old crypt_fs element is deprecated, although it stills works for backward-compatibility reasons. Basically, it is equivalent to setting crypt_method to luks1.

Improve Support for AutoYaST Guided Partitioning

When it comes to partitioning, we can categorize AutoYaST use cases into three different levels:

  • Automatic partitioning: the user does not care about the partitioning and trusts in AutoYaST to do the right thing.
  • Guided partitioning: the user would like to set some basic settings (use LVM, set an encryption password, etc.)
  • Expert partitioning: the user specifies how the layout should look, although a complete definition is not required.

To some extent, it is like using the regular installer where you can skip the partitioning screen and trust in YaST, use the Guided Proposal, or define the partitioning layout through the Expert Partitioner.

The second level (Guided partitioning) was introduced in AutoYaST with the release of SUSE Linux Enteprise 15 (and Leap 15.0) but it was not documented at all. Additionally, although it was working as designed at first sight, it was far from being that useful.

This sprint with invested quite some time improving the documentation (kudos to our awesome documentation team) and the behaviour. Now, if you want to set up an LVM system without having the specify all the details, you can use the following snippet in your profile:

<general>
  <storage>
    <lvm config:type="boolean">true</lvm>
  </storage>
</general>

If you are interested in the available options, you can check the documentation draft.

using YaST firstboot wizard in WSL

November 21st, 2019 by

When starting a WSL distribution for the first time, a text prompt for user name and password appears:

The code for that is partially in the Windows launcher. The Windows side actually prompts for the user name:
https://github.com/microsoft/WSL-DistroLauncher/blob/master/DistroLauncher/DistroLauncher.cpp#L44

and passes it to ‘adduser’:
https://github.com/microsoft/WSL-DistroLauncher/blob/1f8551f7e2ea22bba2e6fb02f01e7a5f7fb757f3/DistroLauncher/DistributionInfo.cpp#L14

That seems to be a Debian specific tool that also prompts for a password. We don’t have it in openSUSE. When done, the Windows part actually calls into the Linux environment again with ‘id -u’ to get the uid of the added user:
https://github.com/microsoft/WSL-DistroLauncher/blob/1f8551f7e2ea22bba2e6fb02f01e7a5f7fb757f3/DistroLauncher/DistributionInfo.cpp#L44

So in order to also prompt for the password we’d have to write a wrapper like the Debian one or implement another prompt in the launcher. Implementing such a prompt in Windows code seems boring to me. When writing a wrapper, I’d do something dialog based to make it look more fancy. There’s already jeos-firstboot that does something similar already and more. But then the WSL image doesn’t have to be really minimal, which means we have YaST!

So even though WSL doesn’t really boot as it has no systemd it would be still possible to run the YaST firstboot wizard on first start. What modules it launches is configurable via xml file. So leaving out hardware/VM specific things like network configuration it works pretty well:


For the launcher to know the name of the created user a small YaST module was needed to write the name into /run/wsl_firstboot_uid. The launcher fetches it from there.

Using the YaST firstboot wizard also allows to use e.g. the existing registration dialogs on SLE or add other useful configuration steps. One feature I have in mind would be for example is the role selection screen to offer some pre defined package selections for WSL use cases.

Tumbleweed and Leap appx files to test this are available from download.opensuse.org. Keep in mind that one needs to import the certificates used by OBS for signing first.

Highlights of YaST Development Sprint 87

October 23rd, 2019 by

It’s time for another YaST team report! Let’s see what’s on the menu today.

  • More news and improvements in the storage area, specially regarding encryption support.
  • Some polishing of the behavior of YaST Network.
  • New widgets in libYUI.
  • A look into systemd timers and how we are using them to replace cron.
  • And a new cool tool for developers who have to deal with complex object-oriented code!

So let’s go for it all.

Performance Improvements in Encrypted Devices

As you may know, we have recently extended YaST to support additional encryption mechanisms like volatile encryption for swap devices or pervasive encryption for data volumes. You can find more details in our blog post titled "Advanced Encryption Options Land in the YaST Partitioner".

Those encryption mechanisms offer the possibility of adjusting the sector size of the encryption layer according to the sector size of the disk. That can result in a performance boost with storage devices based on 4k blocks. To get the best of your systems, we have instructed YaST to set the sector size to 4096 bytes whenever is possible, which should improve the performance of the encrypted devices created with the recently implemented methods.

Additionally, we took the time to improve the codebase related to encryption, based on the lessons we learned while implementing volatile and pervasive encryption. We also performed some additional tests and we found a problem that we are already fixing in the sprint that has just started.

Other improvements related to encryption

One of those lessons we have learnt recently is that resizing a device encrypted with a LUKS2 encryption layer works slightly different to the traditional LUKS1 case. With LUKS2 the password must be provided in the moment of resizing, even if the device is already open and active. So we changed how libstorage-ng handles the passwords provided by the user to make it possible to resize LUKS2 devices in several situations, although there are still some cases in which it will not be possible to use the YaST Partitioner to resize a LUKS2 device.

As a side effect of the new passwords management, now the process that analyzes the storage devices at the beginning of the installation should be more pleasant in scenarios like the one described in the report of bug#1129496, where there are many encrypted devices but the user doesn’t want to activate them all.

And talking about improvements based on our users’ feedback, we have also adapted the names of the new methods for encrypting swap with volatile keys, as suggested in the comments of our already mentioned previous blog post. We also took the opportunity to improve the corresponding warning messages and help texts.

New name and description for encryption with volatile keys

Network and Dependencies Between Devices

Similar to encryption, the network backend is another area that needed some final adjustments after the big implementation done in the previous sprints. In particular, we wanted to improve the management of devices that depend on other network devices, like VLANs (virtual LANs) or bridges.

Historically, YaST has simply kept the name of the device as a dependency, even if such device does not exist any longer. That leaded to inconsistent states. Now the dependencies are updated dynamically. If the user renames a device, then it’s automatically renamed in all its dependencies. If the user deletes a device that is needed by any other one, YaST will immediately ask the user whether to modify (in the case of bonding and bridges) or to remove (in the case of VLANs) those dependent devices.

New libYUI Widget: ItemSelector

Now that we mention the user experience, it’s fair to note that it has been quite a while since we created the last new widget for libYUI, our YaST UI toolkit. But we identified a need for a widget that lets the user select one or many from a number of items with not only a short title, but also a descriptive text for each one (and optionally an icon), and that can scroll if there are more items than fit on the screen.

So say hello to the new SingleItemSelector.

SingleItemSelector in graphical mode

As you would expect from any libYUI widget, there is also a text-based (ncurses) alternative.

SingleItemSelector in text mode

Please, note the screenshots above are just short usage examples. We are NOT planning to bring back the desktop selection screen. On the other hand, now we have the opportunity to make a prettier screen to select the computer role. Stay tuned for more news about that.

There is also an alternative version of the new widget that allows to select several items. The unsurprisingly named MultiItemSelector.

MultiItemSelector in graphical mode

Which, of course, also comes with an ncurses version.

MultiItemSelector in text mode

In the near future, we are planning to use that for selecting products and add-on modules. But this kind of widgets will find other uses as well.

Fun with Systemd Timers

And talking about the close future, many of you may know there is a plan coming together to replace the usage of cron with systemd timers as the default mechanism for (open)SUSE packages to execute periodic tasks.

In our case, we decided to start the change with yast2-ntp-client, which offers the possibility to synchronize the system time once in a while. So let’s take a look to how systemd timers work and how we used them to replace cron.

When defining a service in systemd it is possible to specify a type for that service to define how it behaves. When started, a service of type oneshot will simply execute some action and then finish. Those services can be combined with the timers, which invoke any service according to monotonous clock with a given cadence. To make that cadence configurable by the user, the YaST module overrides the default timer with another one located at /etc/systemd/system.

As a note for anyone else migrating to systemd timers, our first though was to use the EnvironmentFile directive instead of overriding the timer. But that seems to not be possible for timers.

One clear advantage of using a systemd service to implement this is the possibility of specifying dependencies and relations with other services. In our case, that allows us to specify that one time synchronization cannot be used if the chrony daemon is running, since they would both conflict. So the new system is slightly more complex than a one-liner cron script, but it’s also more descriptive and solid.

And another tip for anyone dealing with one-shot services and systemd timers, you can use systemd-cat to catch the output of any script and redirect it to the systemd journal.

Everybody Loves Diagrams

But apart from tips for sysadmins and packagers, we also have some content for our fellow developers. You know YaST is a huge project that tries to manage all kind of inter-related pieces. Often, the average YaST developer needs to jump into some complex module. Code documentation can help to know your way around YaST internals that you don’t work with every day. To generate such documentation, we use the YARD tool, and its output is for example here, for yast-network. Still, for large modules with many small classes, this is not enough to get a good overview.

Enter yard-medoosa, a plugin for YARD that automatically creates UML class diagrams, clickable to get you to the classes textual documentation.

The yast2-network medoosa

It is still a prototype but it has proven useful for navigating a certain large pull request. We hope to soon tell you about an improved version.

More Solid Device Names in fstab and crypttab

Back to topics related to storage management, you surely know there are several ways to specify a device to be mounted in the /etc/fstab file or a device to be activated in the /etc/crypttab. Apart from using directly the name of the device (like /dev/sda1) or any of its alternative names based on udev, you can also use the UUID or the label of the file-system or of the LUKS device.

By default, YaST will use the udev path in s390 systems and the UUID in any other architecture. Although that’s something that can be configured modifying the /etc/sysconfig/storage file or simply using this screen of the Partitioner, which makes possible to change how the installation (both the Guided Setup and the Expert Partitioner) writes the resulting fstab and crypttab files.

Changing the way devices are referenced

But, what happens when the default option (like the udev path) is not a valid option for some particular device? So far, YaST simply used the device name (e.g. /dev/sda1) as an immediate fallback. That happened at the very end of the process, when already writing the changes to disk.

We have improved that for Tumbleweed, for SLE-15-SP1 (which implies Leap 15.1) and for the upcoming versions of (open)SUSE. Now, if the default value is not suitable for a particular device because the corresponding udev path does not exists, because using a given name is incompatible with the chosen encryption method, or for any other reason, YaST will fall back to the most reasonable and stable alternative. And it will do it from the very beginning of the process, being immediately visible in the Partitioner.

Stay Tuned for More… and Stay Communicative

As usual, when we publish our sprint report we are already working on the next development sprint. So in approximately two weeks you will have more news about our work, this time likely with a strong focus in AutoYaST.

Don’t forget to keep providing us feedback. As commented above, it’s very valuable for us and we really use it as an input to plan subsequent development sprints.

openSUSE WSL images in OBS

October 9th, 2019 by

A fundamental concept of all openSUSE packages as well as any image offered for download is a fully transparent, reproducible and automatic build and development process based on sources.

In openSUSE developers do not perform manual builds on some specially crafted machine in their basement and then upload the result somewhere. Instead all sources are stored in a version control system inside the open build service (OBS) instance at build.opensuse.org. OBS then automatically builds the sources including all dependencies according to defined build instructions (eg spec files for rpms). OBS also automatically adds cryptographic signatures to files that support it to make sure nobody can tamper with those files.

The WSL appx files are basically zip files that contain a tarball of a Linux system (like a container) and a Windows exe file, the so called launcher. Building a container is something OBS can already do fully automatic by means of Kiwi. The launcher as well as the final appx however is typically built on a Windows machine using Visual Studio by the developer.

Since the goal of the openSUSE WSL offering is to have the appx files officially and automatically be produced along with other images such as the DVD installer, Live images or containers, the appx files have to be built from sources in OBS.

Fortunately there’s already a MinGW cross toolchain packaged as rpms OBS and a tool to generate appx files on Linux.

Combining that all together OBS can actually build the WSL appx from sources. The current state of development can be found in the Virtualization:WSL project in OBS. The generated appx files are published on download.opensuse.org.
The current images for Leap 15.2 Alpha and Tumbleweed there are good enough for some testing already so please go ahead and do so, feedback welcome!
Note that since the appx files are signed by OBS rather than Microsoft, there are a few steps required to install them.

Going forward there is still quite some work needed to polish this up. Kiwi for example can’t build the appx directly itself but rather the fb-util-for-appx is called by a spec file. That requires some hacks with the OBS project config to work. On Linux side there’s currently no password set for the root user, so we need a better “first boot” solution. More details on that in a later article. Meanwhile, remember to have a lot of fun…

Highlights of YaST Development Sprint 86

October 9th, 2019 by

Now that you had a chance to look at our post about Advanced Encryption Options (especially if you are an s390 user), it is time to check what happened during the last YaST development sprint, which finished last Monday.

As usual, we have been working in a wide range of topics which include:

  • Improving support for multi-device file systems in the expert partitioner.
  • Fixing networking, secure boot and kdump problems in AutoYaST.
  • Stop waiting for chrony during initial boot when it does not make sense.
  • Preparing to support the split of configuration files between /usr/etc and /etc.
  • Using /etc/sysctl.d to write YaST related settings instead of the /etc/sysctl.conf main file.

Expert Partitioner and Multi-Device File Systems

So far, the Expert Partitioner was assuming that Btrfs was the only file system built on top multiple devices. But that is not completely true because some file systems are able to use an external journal to accomplish a better performance. For example, Ext3/4 and XFS can be configured to use separate devices for data and the journaling stuff.

We received a bug report caused by this misunderstanding about multi-device file systems. The Expert Partitioner was labeling as “Part of Btrfs” a device used as an external journal of an Ext4 file system. So we have improved this during the last sprint, and now external journal devices are correctly indicated in the Type column of the Expert Partitioner, as shown in the screenshot below.

External Journal Type

Moreover, the file system information now indicates which device is being used for the external journal.

External Journal Device Details

And finally, we have also limited the usage of such devices belonging to a multi-device Btrfs. Now, you will get an error message if you try to edit one of those devices. In the future, we will extend this feature to make possible to modify file systems using an external journal from the Expert Partitioner.

AutoYaST Getting Some Love

During this sprint, we have given AutoYaST some attention in different areas: networking, bootloader and kdump.

About the networking area, we have finished s390 support in the new network layer, fixing some old limitations in devices activation and udev handling. Apart from that, we have fixed several bugs and improved the documentation a lot, as we found it to be rather incomplete.

Another important change was adding support to disable secure boot for UEFI through AutoYaST. Of course, we updated the documentation too and, during the process, we added some elements that were missing and removed others that are not needed anymore.

Finally, we fixed a tricky problem when trying to get kdump to work on a minimal system. After some debugging, we found out that AutoYaST adds too late kdump to the list of packages to install. This issue has been fixed and now it should work like a charm.

As you may have seen, apart from writing code, we try to contribute to the documentation so our users have a good source of information. If you are curious, apart from the documents for released SUSE and openSUSE versions, you can check the latest builds (including the AutoYaST handbook). Kudos to our documentation team for such an awesome work!

Avoiding chrony-wait time out

Recently, some openSUSE users reported a really annoying issue in Tumbleweed. When time synchronization is enabled through YaST, the system might get stuck during the booting process if no network connection is available.

The problem is that, apart from the chrony service, YaST was enabling the chrony-wait service too. This service is used to ensure that the time is properly set before continuing with other services that can be affected by a time shift. But without a network connection, chrony-wait will wait for around 10 minutes. Unacceptable.

The discussion about the proper fix for this bug is still open, but for the time being, we have applied a workaround in YaST to enable chrony-wait only for those products that require precise time, like openSUSE Kubic. In the rest of cases, systems will boot faster even without network, although some service might be affected by a time shift.

Splitting Configuration Files between /etc and /usr/etc

As Linux users, we are all used to check for system-wide settings under /etc, which contains a mix of vendor and host-specific configuration values. This approach has worked rather well in the past, not without some hiccups, but when things like transactional updates come into play, the situation gets messy.

In order to solve those problems, the plan is to split configuration files between /etc and /usr/etc. The former would contain vendor settings while the latter would define host-specific values. Of course, such a move have a lot of implications.

So during this sprint we tried to identify potential problems for YaST and to propose solutions to tackle them in the future. If you are interested in the technical details, you can read our conclusions.

Writing Sysctl Changes to /etc/sysctl.d

In order to be able to cope with the /etc and /usr/etc split, YaST needs to stop writing to files like /etc/sysctl.conf and use an specific file under .d directories (like /etc/sysctl.d).

So as part of the aforementioned research, we adapted several modules (yast2-network, yast2-tune, yast2-security and yast2-vpn) to behave this way regarding /etc/sysctl.conf. From now on, YaST specific settings will be written to /etc/sysctl.d/30-yast.conf instead of /etc/sysctl.conf. Moreover, if YaST founds any of those settings in the general .conf file, it will move them to the new place.

What’s next?

Sprint 87 is already running. Apart from fixing some bugs that were introduced during the network refactoring, we plan to work on other storage-related stuff like resizing support for LUKS2 or some small snapper problems. We will give your more details in our next sprint report.

Stay tunned!

Advanced Encryption Options Land in the YaST Partitioner

October 9th, 2019 by

Welcome to a new sneak peek on the YaST improvements you will enjoy in SLE-15-SP2 and openSUSE Leap 15.2… or much earlier if you, as most YaST developers, are a happy user of openSUSE Tumbleweed.

In our report of the 84th sprint we mentioned some changes regarding the encryption capabilities of the YaST Partitioner, like displaying the concrete encryption technology or the possibility to keep an existing encryption layer.

Keeping the previous encryption layer

And the report of sprint 85 contained a promise about a separate blog post detailing the new possibilities we have been adding when it comes to create encrypted devices.

So here we go! But let’s start with a small disclaimer. Although some of the new options are available for all (open)SUSE users, it’s fair to say that this time the main beneficiaries are the users of s390 systems, which may enjoy up to four new ways of encrypting their devices.

Good Things don’t Need to Change

As you may know, so far the YaST Partitioner offered an “Encrypt Device” checkbox when creating or editing a block device. If such box is marked, the Partitioner asks for an encryption password and creates a LUKS virtual device on top of the device being encrypted.

LUKS (Linux Unified Key Setup) is the standard for Linux hard disk encryption. By providing a standard on-disk-format, it facilitates compatibility among distributions. LUKS stores all necessary setup information in the partition header, enabling to transport or migrate data seamlessly. So far, there are two format specifications for such header: LUKS1 and LUKS2. YaST uses LUKS1 because is established, solid and well-known, being fully compatible with the (open)SUSE installation process and perfectly supported by all the system tools and by most bootloaders, like Grub2.

You should not fix what is not broken. Thus, in most cases, the screen for encrypting a device has not changed at all and it still works exactly in the same way under the hood.

Editing an encrypted device

But using an alternative approach may be useful for some use cases, and we wanted to offer an option in the Partitioner for those who look for something else. So in some special cases that screen will include a new selector to choose the encryption method. Let’s analyze all those new methods.

Volatile Swap Encryption with a Random Key

When a swap device has been marked to be encrypted, the user will be able to choose between “Regular LUKS1” and “Volatile Encryption with Random Key”. Both options will be there for swap devices on all hardware architectures. The first option simply uses the classical approach described above.

Selecting the encryption method

The second one allows to configure the system in a way in which the swap device is re-encrypted on every boot with a new randomly generated password.

Encrypt swap with a random password

Some advanced users may point that configuring such a random encryption for swap was already possible in versions of openSUSE prior to Leap 15.0. But the procedure to do so was obscure to say the least. The encryption with a random password was achieved by simply leaving blank the “Enter a Password” field in the encryption step. The exact implications were not explained anywhere in the interface and the help text didn’t mention all the risks.

Now the same configuration can be achieved with a more explicit interface, relevant information is provided as you can see in the screenshot below and some extra internal controls are in place to try to limit the potential harm.

Help text for the random swap method

With this approach, the key used to encrypt the content of the swap is generated on every boot using /dev/urandom which is extremely secure. But you can always go a bit further…

Swap Encryption with Volatile Protected AES Keys

One of the nice things about having a mainframe computer (and believe us there are MANY nice things) is the extra security measures implemented at all levels. In the case of IBM Z or IBM LinuxONE that translates into the so-called pervasive encryption. Pervasive encryption is an infrastructure for end-to-end data protection. It includes data encryption with protected and secure keys.

In s390 systems offering that technology, the swap can be encrypted on every boot using a volatile protected AES key, which offers an extra level of security compared to regular encryption using data from /dev/urandom. This document explains how to setup such system by hand. But now you can just use YaST and configure everything with a single click, as shown in the following screenshot.

Encrypting swap with volatile protected keys

The good thing about this method is that you can use it even if your s390 system does not have a CCA cryptographic coprocessor. Oh, wait… you may not know what a cryptographic coprocessor is. Don’t worry, just keep reading.

Pervasive Encryption for Data Volumes

Have you ever wondered how James Bond would protect his information from the most twisted and resourceful villains? We don’t know for sure (or, at least, we are supposed to not disclosure that information), but we would bet he has an s390 system with at least one Crypto Express cryptographic coprocessor configured in CCA mode (shortly referred as a CCA coprocessor).

Those dedicated pieces of hardware, when properly combined with CPU with CPACF support, make sure the information at-rest in any storage device can only be read in the very same system where that information was encrypted. They even have a physical mechanism to destroy all the keys when the hardware is removed from the machine, like the self-destruction mechanisms in the spy movies!

As documented here, the process to enjoy the full power of pervasive encryption for data volumes in Linux can be slightly complex… unless you have the YaST Partitioner at hand!

Pervasive volume encryption

As you can see in the screenshot above, the process with YaST is as simple as choosing “Pervasive Volume Encryption” instead of the classic LUKS1 that YaST uses regularly for non-swap volumes. If YaST finds in the system a secure AES key already associated to the volume being encrypted, it will use that key and the resulting encryption device will have the DeviceMapper name specified for that key. If such secure keys don’t exist, YaST will automatically register a new one for each volume.

Help for pervasive volume encryption

Pervasive encryption can be used on any volume of the system, even the root partition.

I want it all!

So far we have seen you can use protected AES keys for randomly encrypting swap and registered secure keys for protecting data volumes. But what if you want your swap to be randomly encrypted with a volatile secure AES key? After all, you have already invested time and money installing those great CCA coprocessors, let’s use them also for the random swap encryption!

If your hardware supports it, when encrypting the swap you will see a “Volatile Encryption with Secure Key” option, in addition to the other four possibilities commented above. As easy as it gets!

All possible methods for encrypting a swap

More Booting Checks in non-s390 Systems

As described in the help for pervasive volume encryption showed above, that encryption method uses LUKS2 under the hood. So we took the opportunity to improve the Partitioner checks about encryption and booting. Now, in any architecture that is not s390 the following warning will be displayed if the expert partitioner is used to place the root directory in a LUKS2 device without a separate plain /boot.

New check for booting

As mentioned, that doesn’t apply to s390 mainframes. The usage of zipl makes possible to boot Linux in those systems as long as the kernel supports the encryption technology, independently of the Grub2 (lack of) capabilities.

What’s next?

We are still working to smooth off the rough edges of the new encryption methods offered by YaST and to add AutoYaST support for them. You may have noticed that most of the improvements currently implemented will only directly benefit s390 systems… even just a subset of those. But at the current stage, we already have built the foundation for a new era of encryption support in YaSTland.

We are thinking about adding more encryption methods that could be useful for all (open)SUSE users, with general support for LUKS2 being an obvious candidate. But that’s not something we will see in the short term because there are many details to iron up first in those technologies to make then fit nicely into the current installation process.

But hey, meanwhile you can play with all the other new toys!

Highlights of YaST Development Sprint 85

September 26th, 2019 by

Refactored Network on its way to Tumbleweed

A few weeks ago we submitted the first round of changes to the network module to Tumbleweed. At that point, it was still using the old data model for most operations (except routing and DNS handling) and a lot of work remained to be done.

We have been working hard on improving the overall quality of this module and we will submit an updated (and much improved) version in the upcoming days. To summarize, here are some highlights:

  • Completed the new data model (support for TUN/TAP, bridges, bonding, VLANs, etc.).
  • New wireless configuration workflow.
  • Revamped support for interface renaming and driver assignment, including better udev rule handling.
  • Fixed /etc/hosts handling when switching from static to DHCP based configuration.
  • Many small fixes in several areas.

Are we done with the refactoring? No, we are still working on improving S390 support and fixing small issues, but most of the work is already done.

Of course, as soon as we finish, we will publish a blog entry with the gory details. But, as we know that you love screenshots, let us show you a handful of them.

Although we have not introduced big user interface changes, we have tried to improve small things, like properly displaying whether an interface belongs to a VLAN or hiding the "Hardware" tab for virtual interfaces.

DNS resolution not working during installation, or: openQA is different

When we got a bug report that DNS resolution was not working during installation (since SLE-15 apparently), a solution seemed straightforward: /run/netconfig/resolv.conf was missing because the /run directory was not mirrored (bind-mounted) into the target system. That’s a task that used to be done by yast-storage in times before SLE-15 and was for some unknown reason forgotten when we implemented yast-storage-ng. A one-line fix was easily done, tested, and submitted.

Or so it seemed.

A few days later we got reports from SLE openQA that tests started to fail with this patch. Nothing networking related but the installation did not finish because the 10 seconds countdown dialog (‘going to reboot’) at the very end of the installation was frozen. The UI didn’t accept any input whatsoever. But whatever we tried, the issue was not reproducible outside openQA. YaST logs from openQA showed that /run got mounted as planned and was cleanly unmounted at the end of the installation – before that frozen dialog. So no clue so far and the issue was set aside for a while. Until the same reports came in from Tumbleweed testing. It was clearly linked to this one-line patch. But how?

It stayed a mystery until a chat with an openQA expert shed some light on the issue. What we thought was happening was: openQA stopped the dialog (by pressing a button) and when it tried to go on the OK button did not respond anymore. What we learned does actually happen is this: openQA stops the dialog, then switches from X to the text console, collects logs, switches back to X, and then the UI does not respond anymore. So that was quite an essential point missing.

And with this it was easily reproduced outside openQA: the X logs showed that the X server lost all its input devices after the switch. And that was because someone had deleted the whole /run directory. The YaST logs didn’t contain a hint (of course not, would have been too easy) but grepping the sources found the place where YaST deleted the directory.

The code had been added after complaints that the installation left a cluttered /run directory – of course the installation did leave files there, since it was forgotten to bind-mount the directory. So once the mentioned patch bind-mounted it again the deletion code cleaned up not /run in the installation target system but the real /run as well – cutting off the X server from the outside world resulting in freezing the openQA test.

And the moral of the story is: probably none. But it highlights again that the automated test setup can have unexpected feedback on the test itself. Luckily in this case, as the issue would not have been noticed otherwise.

Computer, Enlarge the Device Graph

The partitioner module has a graphical view to help you see the relations in more complex storage setups:

If you turn the mouse scroll wheel up or down, we will zoom the view in or out. Now the direction matches the behavior in web browsers and online maps, previously we had it the wrong way around.

Update: during proofreading, a team mate told me: "A device graph? That’s not a device graph. THAT’s a device graph:"