vole

/home is not deprecated, it's optional but common. Here is the section from FHS: https://refspecs.linuxfoundation.org/FHS_3.0/fhs/ch03s08.html

I'd think so. 3k is so many pixels to compute and send 60 times a second.

But this video says the effect on battery life in their test was like 6%, going from 4k to 800x600. I can imagine that some screens are better at saving power when running at lower resolutions... but what screen manufacturer would optimize energy consumption for anything but maximum resolution? 🤔 I guess the computation of the pixels isn't much compared to the expense of having those physical dots. But maybe if your web browser was ray-traced? ... ?!

Also, if you take a 2880x1800 screen and divide by 2 (to avoid fractional scaling), you get 1440x900 (this is not 1440p), which is a little closer to 720p than 1080p.

I got interested, so I spent some time looking into what's going on here. I'm not intimately familiar with X11 or Wayland, but I figured out some stuff.

Why sudo ip netns exec protected sudo -u user -i doesn't work for X11 apps

Short answer: file permissions and abstract unix sockets (which I didn't know were a thing before now).

File permissions: when I start an X11 login session, the DISPLAY is :0 and /tmp/.X11-unix/ has only 1 file X0. This file has 777 access. When I start my wayland session with Xwayland, the DISPLAY is :1 and /tmp/.X11-unix/ has 2 files X0 (777) and X1 (755). I can't figure out how to connect to display :0, so I guess I'm stuck with :1. When you change to a different (non-root) user, the user no longer has access to /tmp/.X11-unix/X1.

Abstract unix sockets: When I start my wayland/xwayland session, it creates abstract unix sockets with ids @/tmp/.X11-unix/X0 and @/tmp/.X11-unix/X1. See ss -lnp | grep Xwayland. The network namespace also sandboxes these abstract unix sockets. Compare socat ABSTRACT-CONNECT:/tmp/.X11-unix/X1 STDIN and sudo ip netns exec private socat ABSTRACT-CONNECT:/tmp/.X11-unix/X1 STDIN.

When you do sudo ip netns exec protected su - user, you loose access to both the filesystem unix socket /tmp/.X11-unix/X1 and the abstract unix socket @/tmp/.X11-unix/X1. You need access to one or the other for X11 applications to work.

I tried using socat to forward X1 such that it works in the network namespace... and it kinda works. sudo ip netns exec protected socat ABSTRACT-LISTEN:/tmp/.X11-unix/X1,fork UNIX-CONNECT:/tmp/.X11-unix/X1. It appears having ABSTRACT-LISTEN before UNIX-CONNECT is important, I guess it would be worth it to properly learn socat. With this sudo ip netns exec protected su - testuser -c 'env DISPLAY=:1 xmessage hi' works, but sudo ip netns exec protected su - testuser -c 'env DISPLAY=:1 QT_QPA_PLATFORM=xcb kcalc' does not work. 😞

Changing the file permissions on /tmp/.X11-unix/X1 to give the user access seems to work better.

Wayland waypipe

Waypipe works as advertised. But it's still a little bit tricky because you need to have two separate processes for the waypipe client and server, wait for the waypipe socket to be created, adjust file permissions for the waypipe socket file, and set (and probably mkdir) XDG_RUNTIME_DIR.

waypipe -s /tmp/mywaypipe client &
sleep 0.1
chgrp shared-display /tmp/mywaypipe
chmod g+w /tmp/mywaypipe
sudo ip netns exec protected su - testuser -c 'mkdir -p -m 0700 /tmp/runtime-testuser && env XDG_RUNTIME_DIR=/tmp/runtime-testuser waypipe -s /tmp/mywaypipe server -- env QT_QPA_PLATFORM=wayland kcalc'
kill -SIGINT %1

Combined

into this script https://github.com/vole-dev/grabbag/blob/main/run-netns-user-wayland.bash

Completely tangential tip, but in the very-limited video editing I've done recently: I've used Davinci Resolve, rendered as .mov, and then used ffmpeg to render to my actual desired format. e.g. h264 w/ aac audio so I can upload to Youtube:

ffmpeg -i input.mov -c:v libopenh264 -profile:v high -c:a aac -pix_fmt yuv420p output.mp4

I do think that finding the right flags to pass to ffmpeg is a cursed art. Do I need to specify the video profile and the pix_fmt? I don't know; I thought I did when I adventured to collect these flags. Though maybe it's just a reflection of the video-codec horrors lurking within all video rendering pipelines.

edit: there may also be nvidia-accelerated encoders, like h264_nvenc, see ffmpeg -codecs 2>/dev/null | grep -i 'h\.264'. I'm not sure if the profile:v and pix_fmt options apply to other encoders or just libopenh264.

POP!_OS apparently uses systemd-boot (not to be confused with systemd). It apparently adds a Windows entry automatically if Windows is installed on the same disk. When Windows is installed on a different disk, it looks like booting the windows boot manager EFI program is still possible with systemd-boot. The instructions given in that link are a bit vague, though.

This page has a different, simpler approach and more specific steps. Apparently you can just copy the Microsoft EFI folder to a specific directory in your Linux drive's ESP partition. I'd be a little bit concerned about Windows not being able to update its EFI bootloader, but I also don't know if Windows ever updates that. The page also has instructions on how to interact with the systemd-boot menu during boot.

You could also install grub yourself, but I can't guarantee that'll be easy. Mashing F2 might be the sanest solution, unless you plan on booting into Windows every day.

Oh wow, I didn't know (free) Davinci didn't support using H.264 as source media, that feels rather limited.

thanks, I'll try out the libx264 encoder next time

I haven't made a bridge to a VM before today, or made a bridge with Network Manager. That being said, I was able to persuade Network Manger to get a bridge working, and there are a few things I can note:

• When you setup the bridge, the host network interface should become a slave to the bridge. This means that the physical network interface should not have an IP Address, and your bridge should now be where you configure the host's IP address.

  • After you start the VM, you should be able to run ip link | grep 'master br0' on the host, and it should display 2 interfaces which are slaves to br0. One for the physical ethernet interface, one for the VM (vnet). And it should only list your ethernet interface when the VM is off.

• The RedHat tutorial does not show the bridge and the host having different IP addresses, the RedHat tutorial shows the bridge and the guest having different IP addresses. Actually, no, the RedHat tutorial shows the libvirt NAT bridge, not even the bridge that the tutorial describes creating... If you set the IP address of virbr0, I don't know what happens.

• If your VM's network adapter is connected to the host's bridge, then you should be able to log into your VM and set a static IP address.

I had a lot of problems getting Network Manager to actually use my ethernet interface as a slave for the bridge. Here's what worked for me, though:

nmcli con show
nmcli con down 'Wired Connection 1'
nmcli con modify 'Wired Connection 1' connection.autoconnect no
nmcli con add type bridge con-name br0 ifname br0
nmcli connection add type bridge-slave ifname enp7s0 master br0
nmcli con modify br0 connection.autoconnect yes
nmcli con modify bridge-slave-enp7s0 connection.autoconnect yes
nmcli con modify br0 ipv4.method manual ipv4.addresses 172.16.0.231/24 bridge.stp no
sudo systemctl restart NetworkManager.service
nmcli con show
ip addr

• Instead of enp7s0, you'd use enp1s0 I guess.
• Above, I manually set my bridge IP address to a static address because my ethernet interface is wired directly to another computer, so no DHCP for me. If you have DHCP on your ethernet network, you probably don't need to set "ipv4.method" or "ipv4.addresses".
• I set "bridge.stp" to "no" because my network doesn't have any redundant paths, and the stp process seems to take like 25 seconds before I can use the bridge network.

After that, I can go into "Virtual Machine Manger", set my VM's NIC's Network Source to "Bridge device...", Device name to"br0", boot my VM, login to my VM, configure my VM's ip address. And then I can connect to the VM's IP address from the physical ethernet network.

This is a text post, so the OP wrote text corresponding to the title. You should be able to see it at the top of the post. (Spoiler, OP is basically asking the community why NixOS is better, because they don't quite understand the advantages of using NixOS.)