GTALUG Etherpad for May 13, 2020

1 Notes from GTALUG Meeting 2020-05-13

1.1 Running kvm (kernel virtual machine) on Raspberry Pi

  • Yes, it is possible
  • Raspberry PI 3 and above have HW support in the chip and bootloader
  • Possible to run it with docker
  • KVM can run x86 code or ARM code on any machine
  • The problem with ARM – No standard BIOS, an implementations with UEFI and device tree. Not trivial.
  • A version of kubernetes k3s (a simplified version) Runs on Raspberry Pi (containerization not kvm)
  • not a lot of documentation on how to run KVM for raspberry pi
  • Raspberry PI is typically 32-bit vs all of the ‘serious’ containerization projects prefer 64-bit ARM platforms
  • k3s (a sorta cheap Kubernetes) on RPi

1.2 Has anyone tried POP!OS?

  • POP!OS?
  • An Ubuntu derivative
  • Reviews say this is the most beautiful thing since Elementary OS
  • Produced by system76
  • Really nice UI from the experiences
  • GPU drivers seem to be supported on more stable distributions (RHEL & CentOS) and not Fedora (specifically GPU computing from AMD or Nvidia)
  • Fedora 31 hung on used Dell XPS with NVIDIA graphics
    • ubuntu just works (proprietary drivers)
    • fedora 32 has nouveau
  • POP!OS seems to have sensible defaults
  • /r/popos
  • this is where System76 announced POP!OS, in 2017, when Ubuntu stopped working on Unity

1.3 Video conferencing for teaching a-la software carpentry

  • (group breakouts & shared screens in small group only)
  • What is software-carpentry.org
  • Teamviewer available for linux but proprietary as hell (one-on-one)
    • this is the software that the scam artists that cold call you about your “Windows computer being filled with viruses and malware” use to take over your computer
    • that doesn’t imply that it’s evil, just that it’s useful
  • Chris wants to propose using tmux or GNU Screen to share terminals 🙂
  • K12 software (educational group software)
  • Not quite a shared / groupable screen, but we just presented to a conference with OBS, and it worked really well: https://obsproject.com/ [SR]
  • Google meet is pretty analogous to zoom and doesn’t offer extra answers
  • VR rooms that have ‘virtual’ breakout rooms
    • Mozilla hubs doesn’t require VR, allows you to log in with browser (hubs.mozilla.org)
    • https://hubs.mozilla.com/ZSJKAWd/loathsome-wooden-gathering
    • Al SpaceVR (no browser version, goggles required) App that comes with oculus
    • AltSpaceVR accessible with steam client
    • each space has concept of virtual board that can be a board, video or screen

1.4 Let’s set up an etherpad

location is May GTALUG EtherPad

1.5 How do people back up their personal stuff

  • Chris has a horde of little Git repos, anything important gets added to a git repo and pushed places (what does “important” mean???)
  • should automate as much as possible so that we don’t forget to back it up
  • I don’t. I should, but everything is too much hassle or expense. I need something as simple as TimeMachine, but I don’t have bandwidth (or cash) to do a cloud backup [SR]
  • Cronopete claims to be a Time Machine clone for Linux:
  • I have a secondary server, and I have a rsync script that backs up my home directory (and a few others) every night.
  • rclone for encrypted backups with 1 local backup and b2 as remote
  • etckeeper stows /etc in your choice of repos automatically. When you run “apt upgrade”, it automatically checks things in. That doesn’t automatically back up the repo; that also needs to be handled

1.6 Splitting audio and video streams that are still in sync

ffmpeg -re -i $(youtube-dl -g -f 96 https://www.youtube.com/watch?v=9Auq9mYxFEE) -f v4l2 /dev/video2 -f alsa default 
  • Don’t split the streams
  • Video is fed through puredata
  • this has gotta be within OBS’ remit [SR]
  • use OBS to recombine audio and video stream but this is still a problem
  • a/v delay is not always the same

1.7 People’s experiences with PiHole

1.8 GPT harddrives vs Motherboards that do not support GPT

  • The issue might be advanced formatting 512 blocks (legacy) vs 4K blocks (now)
  • Seems to work fine except when it works as a boot device
  • Notes on buying new harddriver for an old system (i.e. Motherboard of 2012 vintage)
  • Try to upgrade BIOS there might be a workaround
  • On a GPT driver you can put fake MBR (older BIOS will see MBR drive, newer MBR will see GPT) This is a horrible hack
    • Refine (website)
      • https://www.rodsbooks.com/
      • lots of information on EFI firmware. Lots of discussion on GPT and Hybrid GPT
      • A lot of details on the website not explained in a beginner-friendly way but it is a great resource
  • Howard’s notes – http://home.eol.ca/~hgibson/Linux.html

1.9 thoughts about the STL trying to merge in the high perfomance C++ folly library from facebook

  • Link to Folly library: https://github.com/facebook/folly
  • I don’t have a mic but the question is about the issues of using out of stream perfomance libraries to fix the gap caused by the STL
  • There is no RCU or high perfomance spinlocks for example.
  • RCU (read-copy-update)
  • Yes it has that but its not a standard so its a problem as your using a third library and having to merge both.
  • You basically have to right a lot of it by hand.

1.10 Kubernetes (K8S)

  • Does anyone know what a “service mesh” is? There are systems: Istio, Consul, Linkerd. Service Mesh gets treated as “otta be obvious what this is”
  • In HA, a service mesh is a “meshing” of components so that if one component fails, others will take over immediately

1.11 Thoughts on these database clients?

  • I’m using the MSSQL one. https://github.com/dbcli (seneca)
    • I’ve been finding typing laggy and it crashes on some commands on certain tables, but at least I don’t end up dealing with FreeTDS [SC}
    • Cannot connect to the MSSQL 2000 server that I still deal with [SC]
  • +1 for DBCLI! (I’m Not Giving My Name To A Machine)

1.12 Cleaning my Laser printer – HP2605DL (Postscript)

  • It’s a colour printer
  • the colour toner seems to have gone cruddy
  • I wiped yellow and green toner off the plastic paper feed; a new supply emerges from somewhere every time I print a sheet
  • Can’t tell where the reservoir of “crud” is 🙁
  • Have you tried the built-in cleaning tool from the manual (page 131)?
    • Not yet, will do…

1.13 Curious Calculators