Graham White: My Notes

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Showing posts from 2024

Debugging Kubernetes PVCs

December 04, 2024

While attempting to create a Tekton Pipeline consisting of multiple tasks recently, I was having a terrible time trying to work out what the various directory definitions were between tasks. These are pre-defined tasks so not ones that I had written myself and hence it can be a bit tricky to try to pick your way through all the various bits of yaml involved. What I really wanted to do (and what helped me debug the issue with my pipeline) was take a look at the content of the PVC (Persistent Volume Claim) that the pipeline was using.

Thanks to a really helpful post, it's quite simple to spin up a little pod that mounts your PVC. You can then exec a shell into the pod and take a look around your PVC.

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  name: pvc-inspector
spec:
  containers:
  - image: busybox
    name: pvc-inspector
    command: ["tail"]
    args: ["-f", "/dev/null"]
    volumeMounts:
    - mountPath: /pvc
      name: pvc-mount
  volumes:
  - name: pvc-mount
    persistentVolumeClaim:
      claimName: pvc-name
EOF

The above will set up a pod that will stay running (thanks to the tail command) and mount your pvc "pvc-name" to /pvc, then all you need to do is start a shell

kubectl exec -it pvc-inspector -- shWhen you're done, you can exit and then delete the pod with
kubectl delete pod pvc-inspector
 

Managing NVidia on Fedora

October 15, 2024

Linus Torvalds has previously had some very choice words to say about NVidia with regards their interaction with open source and Linux. I've spent much of my career using (and battling with) the NVidia drivers on my Linux laptop and these are my notes that make life a little easier and better. For me, NVidia drivers at home on a PC work pretty well. They work less well on a laptop where things are a bit more complicated with external screens, hot plugging of screens, suspend, etc. I've tried the open source alternatives and they really just don't work as well in terms of stability (not that I find the NVidia proprietary Linux drivers especially stable, especially on a modern desktop under Wayland) but also in terms of power management and graphical performance. Hence, I've always concluded I'm better off running the proprietary drivers. If it weren't for the fact that the Lenovo Laptops I use at work have their external monitor connections hard wired to the NVidia card then I would probably just turn off the GPU entirely and rely on the embedded Intel GPU.

Installation

Thankfully, this is pretty simple on Fedora due to the packaging at RPM Fusion. Hence, I think the best way to install the NVidia driver on Fedora is to use the RPM Fusion repository, as follows:

Follow the guide at https://rpmfusion.org/Configuration to install both the free and non-free RPM Fusion repositories
Install the NVidia drivers (see https://rpmfusion.org/Howto/NVIDIA)

It is also best to set your GPU to "discrete only" mode in your UEFI/BIOS.

Note: there is a highly viable alternative repository that also I've run very successfully at Negativo17 and you can, of course, grab the drivers directly from NVidia via their unix downloads page.

Re-Build the NVidia Kernel Module

There are instances where manually kicking off the re-building of the NVidia kernel module can be useful. This can be done very easily as follows:

$ akmodsbuild --kernels $(uname -r) /usr/src/akmods/nvidia-kmod.latest 
$ sudo dnf reinstall <name-of-the-output-rpm-from-above>

Note that the above will rebuild the NVidia kernel module for the current running kernel. You can swap out the $(uname -r) piece of the command for the version string of any of your installed kernel modules to build for a different kernel that you have.

Suspend/Resume Stability

Create a file /etc/modprobe.d/nvidia.conf with the following content:

options nvidia NVreg_PreserveVideoMemoryAllocations=1
options nvidia NVreg_TemporaryFilePath=/var/tmp
options nvidia_drm modeset=1

These should already be on your system after installation but just in case, make sure you have the following RPMs installed by running:

$ sudo dnf install xorg-x11-drv-nvidia-power nvidia-modprobe

Ensure the nvidia suspend/resume services are enabled:

$ sudo systemctl enable nvidia-suspend.service nvidia-hibernate.service nvidia-resume.service

Note: do not enable the nvidia-persistenced.service as this can cause issues on a single GPU machine such as a laptop

Fixing graphical LUKS password prompt

Often, the installation of the NVidia driver can cause the LUKS password prompt to drop back to text mode. This isn't a problem from a functional point of view but it's not so nice to look at as the graphical prompt. If you want to restore the graphical prompt you need to ensure that the NVidia driver is built into your ram disk image. This can be achieved fairly simply, as follows:

Create a file /etc/dracut.conf.d/nvidia.conf and add these lines (note the spaces are required in the quoted strings so that's not a mistake):

add_drivers+=" nvidia nvidia_modeset nvidia_uvm nvidia_drm "
install_items+=" /etc/modprobe.d/nvidia.conf "

With that file in place, you can re-generate your ram disk image by running:

$ sudo dracut -f

Larger console font

Not strictly an NVidia related thing but while I'm on the topic of displays, on HiDPI/4k laptop screens, the console font (seen during the boot process if things go wrong) can be nearly impossible to read as it's far too small. You can resolve this issue by switching your console font to a larger font size.

First, make sure you have the relevant console font(s) installed:

$ sudo dnf install kbd-misc

Next, edit the file /etc/vconsole.conf and change the "FONT=" line to a larger font e.g.

FONT="latarcyrheb-sun32"

Gnome Extensions

April 24, 2024

With the current release of Fedora Linux being updated to version 40 this week, I find myself upgrading to it on the first day of release (rare for me, I usually wait a couple of months) and getting up-to-speed with the changes in Gnome 46. My previous post about Gnome focused on my migration to Gnome 3 and the extensions I was using at the time. During the course of the previous (nearly) 5 years, these have changed quite significantly as the Gnome desktop has grown and as my usage of it has moved on. Hence, rather than update my old post as I have done in previous years, I thought it time to write a whole new post focusing on how I set up my Gnome desktop today.

So without further ado, this is the list of extensions I'm using right now as I write this post (in alphabetical order):

AppIndicator and KStatusNotifierItem Support

This is one of the few extensions that has stood the test of time with my particular usage of Gnome. While the free desktop standard continues to specify the classic "icon tray" that was supported by extensions such as TopIcons, in reality few of the modern desktops (I'm referring to Gnome and KDE) support them. The modern take on the tray icon is an AppIndicator icon and many modern applications are written to use this standard (and perhaps fall back to a tray icon).

Dash to Panel

This is a more recent discovery for me. I've previously evaluated Dash to Dock several times and never liked the user experience. However, the similarly named and with somewhat similar functionality, Dash to Dock has replaced my use of the Window List extension. It provides a more modern alternative to showing which windows I have open with window previews and suchlike. It can do considerably more than the way I've configured it, but I have it set just how I like to work with my Gnome top bar still in tact and a minimal bottom bar used for navigating between my open applications. If you want to try it out with my configuration, I've exported my settings into this GitHub Gist that you can import.

Frippery Panel Favourites

It takes your favourited applications and adds them as a set of icons to the Gnome top panel, making for extra quick access to your commonly used apps. I tend to flip between using this and just searching for apps via the Super button (windows key).

GTile
This great little extension allows you to easily resize your windows in order to tile them across your display. I love the side-snapping in Gnome 3 that allows you to size a window to half the screen size. However, GTile adds an icon to your Gnome Panel that, when clicked, allows you to size to any area of your screen across a pre-defined grid - you can even change the grid size. Brilliant for usability with lots of on-screen windows at the same time. It strikes a great balance for me as someone that generally prefers to tile windows but doesn't like a tiling window manager.

Hide Activities Button

This is almost a little bit superfluous for my usage but I found myself never using the activities button (top left) in the Gnome Panel. The Dash to Panel configuration I have created maintains an activities button (bottom right) which is the place I've grown familiar with in order to use my GUI to switch between desktops (although I generally switch between desktops using keyboard shortcuts).

Pano Clipboard Manager

This is a really great modern take on the clipboard. Press shift+windows+v and you get a pop up at the bottom of the screen with a graphical representation of your clipboard history. The extension is clever enough to be aware of various types of clipboard content such as text, images or hyperlinks. You also get a button on the top panel that allows access to the clipboard, incogneto mode (stops copying stuff to the extension) and settings.

System Monitor Next

Adds little graphs to the Gnome Panel that show resource usage. The extension is pretty configurable but I have it showing CPU, memory and network utilisation. This allows me to keep an easy eye on my machine and how loaded it is at the current time. Extremely useful for spotting those occasional rogue apps that start eating an entire core of my CPU.