Block iiab-install of JupyterHub & Calibre-Web on 32-bit OS's, til RasPiOS fixes Rust, wheels / cryptography

[holta]

These 2 apps should probably not be running on ancient 32-bit "Zero W" machines in the first place!

(But Calibre-Web is part of the MEDIUM-sized IIAB install, so this will help newcomers from getting tripped up installing something that they shouldn't...)

See:

• "Known Issues" at: https://github.com/iiab/iiab/wiki/IIAB-8.0-Release-Notes#known-issues
• @jvonau's suggestion at: Til wheels / cryptography fixed: ansible-core 2.12.10+ PPA on 32-bit RasPiOS #3421 (comment)
• Closed Issue: revert to using pip for ansible on 32bit RasPiOS [& ongoing issues w/ wheels, cryptography, rust] #3459 (comment)

[holta]

Tested on 32-bit RasPiOS Lite.

[holta]

FYI this was further/later tested with 32-bit and 64-bit RasPiOS Lite on RPi 3 and 3 B+.

[holta]

It turns out this PR was flawed — as it delineated between 32-bit and 64-bit HARDWARE — when it should have delineated between 32-bit and 64-bit OS's / SOFTWARE.

As these Ansible variables output the CPU architecture (rather than the OS architecture) — as seen here with the latest 32-bit RasPiOS Lite running on a 64-bit Raspberry Pi:

TASK [debug] *******************************************************************
ok: [127.0.0.1] => {
    "ansible_architecture": "aarch64"
}

TASK [debug] *******************************************************************
ok: [127.0.0.1] => {
    "ansible_machine": "aarch64"
}

On the bright side, avoiding the install of JupyterHub and Calibre-Web is no longer necessary on 32-bit RasPiOS, as confirmed by testing associated with:

• PR venv refinements for consideration, to tighten up scripts/ansible, deferring install of pip unless truly nec #3496

FYI this PR (#3422) will be reverted shortly (7db4dc5) as part of merging the above.

[holta]

It turns out this PR was flawed — as it delineated between 32-bit and 64-bit HARDWARE — when it should have delineated between 32-bit and 64-bit OS's / SOFTWARE.

CORRECTION/CLARIF: 6 months ago, this PR originally delineated properly between 32-bit and 64-bit OS's until mid/late March 2023 when RasPiOS changed...

• Strange switch to 64bit kernel on 32bit RasPiOS [on 64-bit CPU architectures] #3516
• After updating 32 bit Raspi OS Pi 4 is on 64bit kernel raspberrypi/firmware#1795
• raspberrypi-kernel-headers on > 6.1.19 kernel raspberrypi/linux#5408

So any 32-bit RasPiOS apt updated since March 2023 changed its [default kernel boot] behavior in RPi 4 and RPi 400 from... (conversely, there's no change in behavior in RPi 3 !)

TASK [debug] *******************************************************************
ok: [127.0.0.1] => {
    "ansible_architecture": "armv7l"
}

TASK [debug] *******************************************************************
ok: [127.0.0.1] => {
    "ansible_machine": "armv7l"
}

To...

As these Ansible variables output the CPU architecture (rather than the OS architecture) — as seen here with the latest 32-bit RasPiOS Lite running on a 64-bit Raspberry Pi:

TASK [debug] *******************************************************************
ok: [127.0.0.1] => {
    "ansible_architecture": "aarch64"
}

TASK [debug] *******************************************************************
ok: [127.0.0.1] => {
    "ansible_machine": "aarch64"
}

BACKGROUND: Anybody can confirm the above, by running this test:

cd /opt/iiab/iiab
sudo ansible-playbook -i ansible_hosts test.yml --connection=local