Trisquel on ppc64el: Talos II

The release notes for Trisquel 11.0 “Aramo” mention support for POWER and ARM architectures, however the download area only contains links for x86, and forum posts suggest there is a lack of instructions how to run Trisquel on non-x86.

Since the release of Trisquel 11 I have been busy migrating x86 machines from Debian to Trisquel. One would think that I would be finished after this time period, but re-installing and migrating machines is really time consuming, especially if you allow yourself to be distracted every time you notice something that Really Ought to be improved. Rabbit holes all the way down. One of my production machines is running Debian 11 “bullseye” on a Talos II Lite machine from Raptor Computing Systems, and migrating the virtual machines running on that host (including the VM that serves this blog) to a x86 machine running Trisquel felt unsatisfying to me. I want to migrate my computing towards hardware that harmonize with FSF’s Respects Your Freedom and not away from it. Here I had to chose between using the non-free software present in newer Debian or the non-free software implied by most x86 systems: not an easy chose. So I have ignored the dilemma for some time. After all, the machine was running Debian 11 “bullseye”, which was released before Debian started to require use of non-free software. With the end-of-life date for bullseye approaching, it seems that this isn’t a sustainable choice.

There is a report open about providing ppc64el ISOs that was created by Jason Self shortly after the release, but for many months nothing happened. About a month ago, Luis Guzmán mentioned an initial ISO build and I started testing it. The setup has worked well for a month, and with this post I want to contribute instructions how to get it up and running since this is still missing.

The setup of my soon-to-be new production machine:

  • Talos II Lite
  • POWER9 18-core v2 CPU
  • Inter-Tech 4U-4410 rack case with ASPOWER power supply
  • 8x32GB DDR4-2666 ECC RDIMM
  • HighPoint SSD7505 (the Rocket 1504 or 1204 would be a more cost-effective choice, but I re-used a component I had laying around)
  • PERC H700 aka LSI MegaRAID 2108 SAS/SATA (also found laying around)
  • 2x1TB NVMe
  • 3x18TB disks

According to the notes in issue 14 the ISO image is available at and the following commands download, integrity check and write it to a USB stick:

wget -q
tar xfa debian-installer-images_20210731+deb11u8+11.0trisquel14_ppc64el.tar.gz ./installer-ppc64el/20210731+deb11u8+11/images/netboot/mini.iso
echo '6df8f45fbc0e7a5fadf039e9de7fa2dc57a4d466e95d65f2eabeec80577631b7  ./installer-ppc64el/20210731+deb11u8+11/images/netboot/mini.iso' | sha256sum -c
sudo wipefs -a /dev/sdX
sudo dd if=./installer-ppc64el/20210731+deb11u8+11/images/netboot/mini.iso of=/dev/sdX conv=sync status=progress

Sadly, no hash checksums or OpenPGP signatures are published.

Power off your device, insert the USB stick, and power it up, and you see a Petitboot menu offering to boot from the USB stick. For some reason, the "Expert Install" was the default in the menu, and instead I select "Default Install" for the regular experience. For this post, I will ignore BMC/IPMI, as interacting with it is not necessary. Make sure to not connect the BMC/IPMI ethernet port unless you are willing to enter that dungeon. The VGA console works fine with a normal USB keyboard, and you can chose to use only the second enP4p1s0f1 network card in the network card selection menu.

If you are familiar with Debian netinst ISO’s, the installation is straight-forward. I complicate the setup by partitioning two RAID1 partitions on the two NVMe sticks, one RAID1 for a 75GB ext4 root filesystem (discard,noatime) and one RAID1 for a 900GB LVM volume group for virtual machines, and two 20GB swap partitions on each of the NVMe sticks (to silence a warning about lack of swap, I’m not sure swap is still a good idea?). The 3x18TB disks use DM-integrity with RAID1 however the installer does not support DM-integrity so I had to create it after the installation.

There are two additional matters worth mentioning:

  • Selecting the apt mirror does not have the list of well-known Trisquel mirrors which the x86 installer offers. Instead I have to input the archive mirror manually, and fortunately the hostname and path values are available as defaults, so I just press enter and fix this after the installation has finished. You may want to have the hostname/path of your local mirror handy, to speed things up.
  • The installer asks me which kernel to use, which the x86 installer does not do. I believe older Trisquel/Ubuntu installers asked this question, but that it was gone in aramo on x86. I select the default “linux-image-generic” which gives me a predictable 5.15 Linux-libre kernel, although you may want to chose “linux-image-generic-hwe-11.0” for a more recent 6.2 Linux-libre kernel. Maybe this is intentional debinst-behaviour for non-x86 platforms?

I have re-installed the machine a couple of times, and have now finished installing the production setup. I haven’t ran into any serious issues, and the system has been stable. Time to wrap up, and celebrate that I now run an operating system aligned with the Free System Distribution Guidelines on hardware that aligns with Respects Your Freedom — Happy Hacking indeed!

How To Trust A Machine

Let’s reflect on some of my recent work that started with understanding Trisquel GNU/Linux, improving transparency into apt-archives, working on reproducible builds of Trisquel, strengthening verification of apt-archives with Sigstore, and finally thinking about security device threat models. A theme in all this is improving methods to have trust in machines, or generally any external entity. While I believe that everything starts by trusting something, usually something familiar and well-known, we need to deal with misuse of that trust that leads to failure to deliver what is desired and expected from the trusted entity. How can an entity behave to invite trust? Let’s argue for some properties that can be quantitatively measured, with a focus on computer software and hardware:

  • Deterministic Behavior – given a set of circumstances, it should behave the same.
  • Verifiability and Transparency – the method (the source code) should be accessible for understanding (compare scientific method) and its binaries verifiable, i.e., it should be possible to verify that the entity actually follows the intended deterministic method (implying efforts like reproducible builds and bootstrappable builds).
  • Accountable – the entity should behave the same for everyone, and deviation should be possible prove in a way that is hard to deny, implying efforts such as Certificate Transparency and more generic checksum logs like Sigstore and Sigsum.
  • Liberating – the tools and documentation should be available as free software to enable you to replace the trusted entity if so desired. An entity that wants to restrict you from being able to replace the trusted entity is vulnerable to corruption and may stop acting trustworthy. This point of view reinforces that open source misses the point; it has become too common to use trademark laws to restrict re-use of open source software (e.g., firefox, chrome, rust).

Essentially, this boils down to: Trust, Verify and Hold Accountable. To put this dogma in perspective, it helps to understand that this approach may be harmful to human relationships (which could explain the social awkwardness of hackers), but it remains useful as a method to improve the design of computer systems, and a useful method to evaluate safety of computer systems. When a system fails some of the criteria above, we know we have more work to do to improve it.

How far have we come on this journey? Through earlier efforts, we are in a fairly good situation. Richard Stallman through GNU/FSF made us aware of the importance of free software, the Reproducible/Bootstrappable build projects made us aware of the importance of verifiability, and Certificate Transparency highlighted the need for accountable signature logs leading to efforts like Sigstore for software. None of these efforts would have seen the light of day unless people wrote free software and packaged them into distributions that we can use, and built hardware that we can run it on. While there certainly exists more work to be done on the software side, with the recent amazing full-source build of Guix based on a 357-byte hand-written seed, I believe that we are closing that loop on the software engineering side.

So what remains? Some inspiration for further work:

  • Accountable binary software distribution remains unresolved in practice, although we have some software components around (e.g., apt-sigstore and guix git authenticate). What is missing is using them for verification by default and/or to improve the signature process to use trustworthy hardware devices, and committing the signatures to transparency logs.
  • Trustworthy hardware to run trustworthy software on remains a challenge, and we owe FSF’s Respect Your Freedom credit for raising awareness of this. Many modern devices requires non-free software to work which fails most of the criteria above and are thus inherently untrustworthy.
  • Verifying rebuilds of currently published binaries on trustworthy hardware is unresolved.
  • Completing a full-source rebuild from a small seed on trustworthy hardware remains, preferably on a platform wildly different than X86 such as Raptor’s Talos II.
  • We need improved security hardware devices and improved established practices on how to use them. For example, while Gnuk on the FST enable a trustworthy software and hardware solution, the best process for using it that I can think of generate the cryptographic keys on a more complex device. Efforts like Tillitis are inspiring here.

Onwards and upwards, happy hacking!

Update 2023-05-03: Added the “Liberating” property regarding free software, instead of having it be part of the “Verifiability and Transparency”.