Installing and Maintaining Debian Unstable

Updated on 2023-01-07

Contents

• 1 – Introduction
• 2 – Things to Consider Before Deciding to Use Debian Unstable
• 3 – Debian Unstable Installation
  • 3.01 – Disable Automatic Removal of Old Kernels
  • 3.02 – Enable GRUB OS Prober
• 4 – System Upgrades
  • 4.01 – Normal Full-Upgrade
  • 4.02 – Packages Flagged as No Longer Required (Autoremovals)
  • 4.03 – Kernel Upgrades
  • 4.04 – Problematic Full-Upgrade – Package Bug Encountered
  • 4.05 – Problematic Full-Upgrade – Holding a Package Results in Undesired Packages to Be Removed or Packages Being Undesirably Flagged as No Longer Required
  • 4.06 – Problematic Full-Upgrade – Undesired Packages to Be Removed or Packages Being Undesirably Flagged as No Longer Required
  • 4.07 – Persistent Proposed Package Removals
  • 4.08 – Transitions
  • 4.09 – Downgrading a Buggy Package
  • 4.10 – After a New Debian Stable Release
  • 4.11 – Purging the Package Cache
• 5 – Conclusion
• 6 – Useful Resources

1 – Introduction

Debian Unstable, also known as Debian Sid (Sid being the Toy Story character who likes to destroy toys), is part of the development process for Debian Stable. Packages typically flow in the following order during the Debian Stable development process:

• Experimental
• Unstable
• Testing
• Stable

Approximately every two years, development is frozen and eventually Debian Testing becomes the next Debian Stable release.

While the primary purpose of Debian Unstable is for the development of the next Debian Stable release, it can also be used as a daily operating system. Used as a daily operating system, Debian Unstable is considered to be a rolling release. In other words, unless the installation breaks, you should never have to install it again. However, you need to know quite a bit about maintaining Debian Unstable as it is prone to breaking.

My first encounter with Debian Unstable was when a user who went by the username machinebacon (real name Julius Hader) in the CrunchBang Linux forums put together a tutorial on running CrunchBang Linux using Debian Unstable. I was intrigued with running CrunchBang Linux using Debian Unstable because Debian Unstable had newer packages, or as they used to say in the CrunchBang Linux forums, new shiny stuff.

In this tutorial, I’m going to detail how to install Debian Unstable and I will also provide tips on maintaining Debian Unstable.

2 – Things to Consider Before Deciding to Use Debian Unstable

Debian Unstable is not difficult to use and maintain once you become proficient with both activities. However, you should have some Linux experience, particularly experience with using Debian Stable, before deciding to use Debian Unstable. This consideration is particularly applicable to new Linux users.

Security updates for packages in the Debian Unstable repositories are not provided by the Debian Security Team. Any security patches are acquired from the package maintainer. Therefore, it’s possible to obtain packages under Debian Unstable that have security issues.

By its very nature, Debian Unstable is prone to breakage. It is advisable not to perform a system upgrade if you need to use Debian Unstable to get something important done the same day. However, this consideration is not as important once you become proficient at maintaining and troubleshooting package installation and/or package upgrade issues under Debian Unstable.

The result of following this tutorial is a barebones system; i.e. you will not have a desktop environment or any applications other than a command line editor. If you’re a fan of the Openbox window manager and the Tint2 panel, reference this post to setup a usable system. Otherwise, you’ll have to know how to install your preferred desktop environment and applications to create a usable system or you could opt to install the Siduction Linux distribution.

Siduction is based on Debian Unstable, with a customized kernel, scripts, tools, and documentation available in the Siduction repository. Siduction is currently available with the following desktop environments: Cinnamon, KDE, XFCE, LXDE, and Gnome. Additionally, the development team also offers an installable version with no GUI called NoX (no X Window System) and an Xorg (X Windown System) version, which I assume is very similar to a Debian minimal system.

If you opt to install Siduction, insure that apt-listbugs is installed. Everything in section 4, covering system upgrades, of this tutorial will also work under Siduction since it is based on Debian Unstable.

3 – Debian Unstable Installation

The Debian recommended method of creating a Debian Unstable installation is to use a current Debian Stable installer to create a minimal system; i.e. no desktop, no programs. I’m not going to cover the installation of Debian Stable in this tutorial. Feel free to checkout my tutorial on installing a Debian Stable minimal system using the network installation method. This tutorial assumes you have already installed a minimal Debian Stable system.

To upgrade your Debian Stable minimal system to Debian Unstable, you will do two things. First, you need to change the applicable apt sources file. In my tutorial on installing a Debian Stable minimal system using the network installation method, I suggested creating a file named debian.list under the /etc/apt/sources.list.d folder as a replacement for /etc/apt/sources.list. Using nano, enter the following command:

– or –

Change whatever is in the existing file to read as follows and then save (CTRL-X) your changes:

deb [repository address] unstable main contrib non-free
# deb-src [repository address] unstable main contrib non-free

Now upgrade your system to Debian Unstable using the following commands:

That’s it! You now have a Debian Unstable minimal system. However, there are two programs that I recommend installing in addition to whatever other programs you plan to install; apt-listbugs and apt-listchanges. apt-listchanges should be installed by default. To install apt-listbugs:

apt-listbugs will check for bug reports for any packages about to be installed or upgraded, providing you the opportunity not to install or upgrade the package if you deem the bug to be applicable and severe enough. I will cover more about making that determination later in this tutorial, as well as how to prevent an unwanted upgrade.

apt-listchanges will notify you of important changes to an upgraded package when applicable.

3.01 – Debian Unstable Installation – Disable Automatic Removal of Old Kernels

On 01/08/2021, the upgrade to apt version 2.1.16 introduced new functionality to automatically remove old kernels. I recommend disabling the automatic removal of old kernels as follows:

1. Locate the line VersionedKernelPackages.
2. Place a hashtag (#) in front of “linux-.*”;.
3. Save your changes; CTRL-O.
4. Exit Nano; CTRL-X.

The above tip is courtesy of a forum member who goes by the username devil on the Siduction forums.

Why do I recommend disabling the removal of old kernels? Because a newer kernel has the potential of causing issues with your computer, especially if it is an older computer.

3.02 – Debian Unstable Installation – Enable GRUB OS Prober

With the GRUB v2.06-1 upgrade in late November 2021, boot menu entries for other operating systems are no longer generated by default; a ridiculous default in my opinion. To re-enable the generation of boot menu entries for other operating systems, enter the following on the command line:

1. Go to the bottom of the file, add another new line (one should already exist), and enter the following:

# Your comment of choice
GRUB_DISABLE_OS_PROBER=false

2. Make sure there is a blank line following the last line above.
3. Save your changes; CTRL-O.
4. Exit Nano; CTRL-X.
5. Then enter the following on the command line:

4 – System Upgrades

Debian Unstable receives many new packages on a daily basis. If you wait a week or longer to perform a system upgrade, you can encounter situations where there are 100 or more packages that are upgraded, which is quite different from Debian Stable. You may also encounter instances where new packages get installed and installed packages get removed. System upgrades in Debian Unstable are mainly performed in one of two ways:

– or –

apt full-upgrade can potentially involve the undesirable removal of packages. The removal of packages isn’t always a bad thing. Sometimes a newer package has been created or sometimes the package is no longer needed. Sometimes though, you may encounter large upgrade transitions or you may have accessed a repository that hasn’t received all of the necessary package upgrades. A red flag should be raised in your mind though when you see desirable packages that will be removed or are flagged as no longer required; e.g. libc6 or main apps like LibreOffice, GIMP, File Roller, etc.

apt upgrade will not involve the undesirable removal of packages. apt upgrade is a safer option to use when encountering situations as depicted in the last sentence of the previous paragraph about apt full-upgrade. However, sometimes just holding a package will allow you to safely perform an apt full-upgrade without the undesirable removal of a package(s).

Debian Unstable should be updated on a regular basis. Waiting months to upgrade a Debian Unstable installation is not a recommended practice. One might ask, “What is a regular basis?” You should aim to upgrade Debian Unstable on a weekly basis. I have updated Debian Unstable as frequently as every other day, but doing so increases the risk of running into problematic full-upgrades. However, I have found that updating every other day results in a lot fewer package upgrades, which in my opinion seems easier to manage.

Because of the rolling nature of Debian Unstable and the fact that package upgrades can result in breakage or a broken system, I highly recommend logging your package activity (installs, removals, upgrades) using your favored note taking application. Logging your package activity can aid you in tracking down the cause of system issues, particularly after system upgrades.

4.01 – System Upgrades – Normal Full-Upgrade

Following is an example of a normal apt full-upgrade; i.e. no undesirable packages flagged as no longer required, no packages to be removed, and no bug reports.

In this example, you can feel fairly confident that an apt full-upgrade will be trouble-free, although there is no guarantee. Just because there hasn’t been a bug report filed for any of the packages being upgraded doesn’t mean that you will not encounter a bug.

4.02 – System Upgrades – Packages Flagged as No Longer Required (Autoremovals)

You will sometimes encounter occasions where packages are flagged as no longer required.

In many instances, it is okay to go ahead and remove packages flagged as no longer required. As stated in the proposed actions, you can remove packages that are no longer required using the following command:

I generally remove packages flagged as no longer required after upgrading the system.

You may encounter instances where packages are flagged as no longer required when they shouldn’t be. I’ll cover those instances later in this tutorial.

4.03 – System Upgrades – Kernel Upgrades

If you’ve opted to disable automatic kernel removals, when a newer kernel is installed the older kernel will be marked as no longer required.

You can’t remove the older kernel because it will still be in use. Additionally, you probably shouldn’t remove the older kernel until you’re sure the newer kernel does not introduce undesirable system issues. Once you’ve rebooted your system and feel comfortable that the new kernel is not causing issues, you can remove the older kernel by issuing the following command on the command line:

4.04 – System Upgrades – Problematic Full-Upgrade – Package Bug Encountered

Following is an example of performing an apt full-upgrade where a package bug is encountered:

When encountering a bug, you should lookup the bug report(s) to determine if you need to hold the package(s) in question. You can lookup bugs for the Debian distribution using the Debian bug tracking system.

You can lookup bugs using a variety of criteria, but I usually lookup the bug using the bug number. In the above example, I determined that the git bug warranted holding the existing version of git; i.e. not allowing git to be upgraded. To hold a package, enter the following command:

If you have multiple packages that you want to hold, just enter each package name separated by a space.

Learning how to determine if a bug report for a package warrants holding a package will come with experience. When I’m not sure, I hold the package.

After marking the git package for hold, an apt full-upgrade would result in the following actions:

The git-man package was automatically kept back or held as a result of marking the git package for hold. After performing the apt full-upgrade, you should unhold any held packages as follows:

Again, multiple packages can be listed separately using a space between each package name.

Because Debian Unstable is very similar to a rolling release Linux distribution, indefinitely holding a package is not recommended. Doing so may result in a broken system.

4.05 – System Upgrades – Problematic Full-Upgrade – Holding a Package Results in Undesired Packages to Be Removed or Packages Being Undesirably Flagged as No Longer Required

Sometimes holding a package due to a bug report can result in undesired packages being removed or packages being undesirably flagged as no longer required.

In the above example, I had held the package libpython3.9 due to a bug report. However, holding the libpython3.9 package resulted in the undesirable flagging of multiple packages as no longer required and the undesirable proposed removal of other packages. In such instances as this, it’s better to run an apt upgrade instead of an apt full-upgrade.

Following were the proposed actions when running apt upgrade:

Don’t forget to unhold any held packages:

4.06 – System Upgrades – Problematic Full-Upgrade – Undesired Packages to Be Removed or Packages Being Undesirably Flagged as No Longer Required

Performing an apt full-upgrade can sometimes result in the undesirable removal of packages or packages being undesirably flagged as no longer required:

In the above example, a large Perl transition was underway. In situations like this, it’s better to run an apt upgrade instead of an apt full-upgrade. Following were the proposed actions for an apt upgrade:

4.07 – System Upgrades – Persistent Proposed Package Removals

It’s possible to experience instances where you continue to encounter a proposed package removal during an apt full-upgrade. You could hold such packages, and there are some instances where that is desirable. However, due to the rolling nature of Debian Unstable, it’s generally not recommended to hold a package indefinitely.

In some instances, you can allow a package to be removed and then re-install it. I haven’t learned when to determine when such instances are warranted. When I encounter persistent proposed package removals, I present the issue over on the Siduction Upgrade Warnings forum. Some of the forum members have contacts with the Debian development team and one of the Siduction forum members will usually let you know when it is best to allow a package removal.

Sometimes, a package can get removed and then the package is later included as a new install. Such instances are just part of the nature and purpose of Debian Unstable; refer to the introduction in this tutorial.

4.08 – System Upgrades – Transitions

Transitions can result in the undesirable removal of packages, or the undesirable flagging of packages as no longer required. I check the Siduction Upgrade Warnings forum for news on transitions. Note that transition news reported in the Siduction Upgrade Warnings forum may not always apply to you, depending upon the packages you have installed. Many of the Siduction forum members seem to run the KDE desktop environment (I don’t) based on the time I’ve spent reading the forums.

Another source for monitoring transitions is the Debian Release Management – Transition tracker. However, I’ve not been able to learn to use the resource well enough for it to be useful to me.

You could also subscribe to or view the debian-devel mailing list. Sometimes large transitions are announced via the mailing list.

4.09 – System Upgrades – Downgrading a Buggy Package

It is possible to upgrade a package that turns out to have an unreported bug, rendering an important application unusable or causing system breakage. What should you do in such circumstances? You have two options.

First, installing or upgrading a package results in an associated *.deb file being stored under /var/cache/apt/archives, also known as the package cache or local repository. I prefer the term package cache, so hereinafter I will use that term. Locate the desired package if still available and re-install it using the following command:

The -i option forces the installation of an earlier version of a package.

Another option is to visit the Debian Snapshot Service, searching for the binary version of your desired package over on the left side of the main page under Packages. Once you have located and downloaded the desired package (should be in *.deb format), install it using the same method referenced above, substituting the applicable path to the downloaded file.

Warning: Use package downgrading judiciously. Make sure you understand any possible repercussions of downgrading a package. Downgrading some packages, e.g. libc6, could break your system.

4.10 – System Upgrades – After a New Debian Stable Release

At some point, the Debian Release Team decides to freeze any further inflow of new packages, with some exceptions, into the Debian Testing repository in preparation for the release of the next version of Debian Stable. Eventually that means there will be very few, and sometimes no, updates when you perform an apt full-upgrade or even an apt upgrade. So a backlog of newer packages will await the release of Debian Stable.

Once Debian Stable is released, the backlog of newer packages flows into Debian Unstable. When you perform an apt full-upgrade, you’ll be presented with hundreds of proposed actions, including new package installs, package removals, packages flagged as no longer required, and packages to be upgraded. Therefore, the general recommendation that I’ve learned from others is to wait about a week after the release of a new version of Debian Stable before attempting to perform an apt full-upgrade. You can also check the Siduction Upgrade Warnings forum to see if and when it is safe to commence system upgrades following the release of a new Debian Stable release.

4.11 – System Upgrades – Purging the Package Cache

As mentioned previously, the act of installing and upgrading packages results in the storage of *.deb files under /var/cache/apt/archives, also known as the package cache. It’s a good practice to clean up the package cache routinely to free up drive space. To purge the package cache, enter the following command:

5 – Conclusion

I enjoy using Linux rolling release distributions because of the newer packages that are available. I hope the tips in this tutorial prove helpful should you choose to use Debian Unstable as your daily driver.

I owe a great deal of thanks to Julius Hader (aka machinebacon) whose post on running CrunchBang Linux using the Debian Unstable repositories began my journey on using Debian Unstable on a regular basis. Julius also helped me out a great deal when I decided to use CrunchBang Linux full time back in 2012.

I also owe a great deal of thanks to members of the former CrunchBang Linux forums, as well as members of the BunsenLabs forums, who helped me at times when I ran into problems using Debian Unstable.

Finally, I owe a great deal of thanks to the members of the Siduction forums who have helped, and continue to help, me immensely with becoming proficient at running Debian Unstable.

If you have a question or comment, leave it in the Comment box at the bottom of the page.

6 – Useful Resources

Most of the sites below have been referenced within this post, but I’m also listing them here as a concise handy reference.

• BunsenLabs Forums
• Debian Administrators Handbook
• debian-devel Mailing List
• Debian Packages
• Debian Release Management – Transition Tracker
• Debian Snapshot Service
• Debian User Forums
• Debian Wiki – Debian Unstable
• Debian Worldwide Mirror Sites
• Siduction Linux Distribution
• Siduction Upgrade Warnings Forum

Post header image courtesy of linux-apps.com, GPLv2 or later licensed.

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