Technology Tales

What to do when a GPG signature becomes invalid for a package repository on Linux Mint

During a package update on my main Linux system, I encountered the following kind of error message:

An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://cli.github.com/packages stable InRelease: The following signatures were invalid: EXPKEYSIG <GPG Key> GitHub CLI

The message indicated a problem with the GPG signature verification for the GitHub CLI repository. The cause was that the signature for the repository was invalid, preventing the package manager from updating the repository's index files. The first step then was to remove the invalid GPG key using the following command:

sudo apt-key del <GPG Key>

With the invalid GPG key removed, the next step is to add the new GPG key for the GitHub CLI repository by issuing the following command:

curl -fsSL https://cli.github.com/packages/githubcli-archive-keyring.gpg | sudo tee /usr/share/keyrings/githubcli-archive-keyring.gpg > /dev/null

Once I had the new GPG key, I was able to use my usual system update process without any problem. The error message was gone, and updates and upgrades proceeded as intended.

Resolving "repository doesn't support architecture i386" error when checking for updates to Brave Browser on Linux

Recently, I started to observe the following message when doing my usual update routine on Linux Mint (Debian, Ubuntu and their variants are likely affected as well):

N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository 'https://brave-browser-apt-release.s3.brave.com stable InRelease' doesn't support architecture 'i386'

As the message suggests, there was something amiss with the repository set up for Brave, a browser that I added for extra privacy. Since Firefox remains the main one that I use, Brave is something that I have in hand for when I need it. Handily, its installation routine adds in repository information for keeping it up to date. However, there is an issue with what you find in /etc/apt/sources.list.d/brave-browser-release.list. By default, the line appears like thus:

deb [signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg] https://brave-browser-apt-release.s3.brave.com/ stable main

To avoid the i386 error, it needs to look like this instead:

deb [signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg arch=amd64] https://brave-browser-apt-release.s3.brave.com/ stable main

The difference between the tow is the presence of arch=amd64 in the second version. This stops the search for non-existent i386 files, the 32 bit version in other words. With Y2K2038 in the offing, the days of 32 bit computing architectures are numbered because there is a real limit to the magnitude of the dates that can be represented in any case. Thus, sticking with 64 bit ones is both the present for many and the future for all.

Getting rid of the "Get more security upgrades through Ubuntu Pro with 'esm-apps' enabled" message when performing a system update

Not so long ago, I got the above message while running sudo apt upgrade on an Ubuntu Server system. This was not the first time that this kind of thing happened to me, so I started searching the web for a solution. You do get to see complaints about advertising, but these are never useful.

Accordingly, here are some possible ways of remediating the situation:

• Execute the following commands to disable the responsible services, renaming the configuration file to prevent it from being used (deleting or editing the configuration file to remove the unwanted content are other options):

  sudo systemctl mask apt-news.service

  sudo systemctl mask esm-cache.service

  sudo mv /etc/apt/apt.conf.d/20apt-esm-hook.conf
/etc/apt/apt.conf.d/20apt-esm-hook.conf.disabled

• Alternatively, simply remove the ubuntu-advantage-tools package, which contains the /etc/apt/apt.conf.d/20apt-esm-hook.conf file.
• Another option is to remove the ubuntu-pro-client package.
• Lastly, there also is the possibility of enabling ESM, though that was not desirable for me.

In my case, it may have been the penultimate option on the list that I chose. In any case, I was rid of the unwanted message.

Removing redundant kernels from Ubuntu

Recently, a message appeared on some web servers that I have that exhorted me to upgrade to Ubuntu 22.04.1 using the do-release-upgrade command. In the interests of remaining current, I did just that to get another message, one like the following:

The upgrade needs a total of [amount of space with units] free space on disk `/boot`.
Please free at least an additional [amount of space with units] of disk space on `/boot`.
Empty your trash and remove temporary packages of former installations
using `sudo apt-get clean`.

Using sudo apt-get clean did not resolve the problem, so the advice given was of no use. The actual problem was that there were too many old kernels cluttering up /boot and searching around the web provided that wisdom. What also came up was a single command for resolving the problem. However, removing the wrong kernel can wreck a system, ensuring that I took a more cautious approach. First, I listed the kernels to be removed and checked that they did not include the currently running one. This was done with the following command (broken up over several lines for clarity using the backslash character to denote continuation) and running uname -r found the details of the running kernel:

dpkg -l linux-{image,headers}-"[0-9]*" \

| awk '/ii/{print $2}' \

| grep -ve "$(uname -r \

| sed -r 's/-[a-z]+//')"

The dpkg command listed the installed kernels with awk, grep and sed filtering out unwanted sections of the text. The awk command takes the tabular output from dpkg and turns it into a list. The -v switch on the grep command gets the lines that do not match the search expression created by the sed command, while the -e switch makes grep look for patterns. The sed command removes all letters from the output of the uname command, where the -r switch produces the kernel release details, to leave on the release number of the current kernel. On being satisfied that nothing untoward would happen, the full command below (also broken up over several lines for clarity, using the backslash character to denote continuation) could be executed.

sudo apt purge $(dpkg -l linux-{image,headers}-"[0-9]*" \

| awk '/ii/{print $2}' \

| grep -ve "$(uname -r \

| sed -r 's/-[a-z]+//')")

This apt to purge the unwanted kernels, thus freeing up enough space for the upgrade to continue. That happened without significant incident, though there were some remediations needed on the PHP side to get the website working smoothly again.

Fixing an Ansible warning about boolean type conversion

My primary use for Ansible is doing system updates using the inbuilt apt module. Recently, I updated my main system to Linux Mint 21 and a few things like Ansible stopped working. Removing instances that I had added with pip3 sorted the problem, but I then ran playbooks manually, only for various warning messages to appear that I had not noticed before. What follows below is one of these.

[WARNING]: The value True (type bool) in a string field was converted to u'True' (type string). If this does not look like what you expect, quote the entire value to ensure it does not change.

The message is not so clear in some ways, not least because it had me looking for a boolean value of True when it should have been yes. A search on the web revealed something about the apt module that surprised me.: the value of the upgrade parameter is a string, when others like it take boolean values of yes or no. Thus, I had passed a bareword of yes when it should have been declared in quotes as "yes". To my mind, this is an inconsistency, but I have changed things anyway to get rid of the message.

Getting rid of the Windows Resizing message from a Manjaro VirtualBox guest

Like Fedora, Manjaro also installs a package for VirtualBox Guest Additions when you install the Linux distro in a VirtualBox virtual machine. However, it does have certain expectations when doing this. On many systems, and my own is one of these, Linux guests are forced to use the VMSVGA virtual graphics controller while Windows guests are allowed to use the VBoxSVGA one. It is the latter that Manjaro expects, so you get a message like the following appearing when the desktop environment has loaded:

Windows Resizing
Set your VirtualBox Graphics Controller to enable windows resizing

After ensuring that gcc, make, perl and kernel headers are installed, I usually install VirtualBox Guest Additions myself from the included ISO image, and so I did the same with Manjaro. Doing that and restarting the virtual machine got me extra functionality like screen resizing and being able to copy and paste between the VM and elsewhere after choosing the Bidirectional setting in the menus under Devices > Shared Clipboard.

That still left an unwanted message popping up on startup. To get rid of that, I just needed to remove /etc/xdg/autostart/mhwd-vmsvga-alert.desktop. While it can be deleted, I just moved it somewhere else and a restart proved that the message was gone as needed. Now everything is working as I wanted.

Resolving VirtualBox Shared Folders problems in Fedora 32 through a correct Guest Additions installation

While some Linux distros like Fedora install VirtualBox drivers during installation time, I prefer to install the VirtualBox Guest Additions themselves. Before doing this, it is best to remove the virtualbox-guest-additions package from Fedora to avoid conflicts. After that, execute the following command to ensure that all prerequisites for the VirtualBox Guest Additions are in place before mounting the VirtualBox Guest Additions ISO image and installing from there:

sudo dnf -y install gcc automake make kernel-headers dkms bzip2 libxcrypt-compat kernel-devel perl

During the installation, you may encounter a message like the following:

ValueError: File context for /opt/VBoxGuestAdditions-<VERSION>/other/mount.vboxsf already defined

This is generated by SELinux, so the following commands need to be executed before repeating the installation of VirtualBox Guest Additions:

sudo semanage fcontext -d /opt/VBoxGuestAdditions-<VERSION>/other/mount.vboxsf
sudo restorecon /opt/VBoxGuestAdditions-<VERSION>/other/mount.vboxsf

Without doing the above step and fixing the preceding error message, I had an issue with mounting of Shared Folders whereby the mount point was set up, but no folder contents were displayed. This happened even when my user account was added to the vboxsf group, and it proved to be the SELinux context issue that was the cause.

Removing obsolete libraries from Flatpak

Along with various pieces of software, Flatpak also installs KDE and GNOME libraries needed to support them. However, it does not always remove obsolete versions of those libraries whenever software gets updated. One result is that messages regarding obsolete versions of GNOME may be issued and this has been known to cause confusion because there is the GNOME instance that is part of a Linux distro like Ubuntu and using Flatpak adds another one for its software packages to use. My use of Linux Mint may lessen the chances of misunderstanding.

Thankfully, executing a single command will remove any obsolete Flatpak libraries so the messages no longer appear and there then is no need to touch your actual Linux installation. This then is the command that sorted it for me:

flatpak uninstall --unused && sudo flatpak repair

The first part that removes any unused libraries is run as a normal user, so there is no error in the above command. Administrative privileges are needed for the second section that does any repairs that are needed. It might be better if Flatpak did all this for you using the update command, but that is not how the thing works. At least, there is a quick way to address this state of affairs and there might be some good reasons for having things work as they do.

Ensuring that Flatpak remains up to date on Linux Mint 19.2

The Flatpak concept offers a useful way of getting the latest version of software like LibreOffice or GIMP on Linux machines because repositories are managed conservatively when it comes to the versions of included software. Ubuntu has Snaps, which are similar in concept. Both options bundle dependencies with the packaged software so that its operation can use later versions of system libraries than what may be available with a particular distribution.

However, even Flatpak depends on what is available through the repositories for a distribution, as I found when a software update needed a version of the tool. The solution was to add PPA using the following command and agreeing to the prompts that arise (answering Y, in other words):

sudo add-apt-repository ppa:alexlarsson/flatpak

With the new PPA instated, the usual apt commands were used to update the Flatpak package and continue with the required updates. Since then, all has gone smoothly as expected.

Shared folders not automounting on an Ubuntu 18.04 guest in a VirtualBox virtual machine

Over the weekend, I finally got to resolve a problem that has affected Ubuntu 18.04 virtual machine for quite a while. The usual checks on Guest Additions installation and vboxsf group access assignment were performed but were not causing the issue. Also, no other VM (Windows (7 & 10) and Linux Mint Debian Edition) on the same Linux Mint 19.2 machine was experiencing the same issue. The latter observation made the problem intrinsic to the Ubuntu VM itself.

Because I install the Guest Additions software from the included virtual CD, I executed the following command to open the relevant file for editing:

sudo systemctl edit --full vboxadd-service

If I had installed virtualbox-guest-dkms and virtualbox-guest-utils from the Ubuntu repositories instead, then this would have been the command that I needed to execute instead of the above.

sudo systemctl edit --full virtualbox-guest-utils

Whichever configuration gets opened, the line that needs attention is the one beginning with "Conflicts" (line 6 in the file on my system). The required edit removes systemd-timesync.service from the list following the equals sign. It is worth checking that file paths include the correct version number for the Guest Additions software that is installed, in case this is not how things are. The only change that was needed on my Ubuntu VM was to the Conflicts line, and rebooting it got the Shared Folder automatically mounted under the /media directory as expected.