CHG-0046: The Backend Pi Is on Its Cable Alone
| Date | 2026-10-30 |
| Change type | Configuration |
| Status | Complete |
| Systems | The home backend Pi, eds-backend; the backend image (images/backend) and deploy/backend/card.sh |
| How | nmcli on the Pi, over its cable; the image’s playbook and card.sh changed for the next card |
| Risk | Low. Most likely to go wrong: the session that makes the change riding the Wi-Fi it removes, which connecting to the wired address prevents |
| Decisions | None of its own. It is ADR-0053’s “radio off by default” before that record’s window is built, and CHG-0028’s “one address at home” |
| Related | CHG-0042, whose card asked for Wi-Fi; CHG-0028 |
Summary
The backend Pi had two addresses on the home network: 192.168.2.40 on its
cable and 192.168.2.228 on Wi-Fi. Both were on DVNT-CORE. The Wi-Fi was
deevnet-kit-wifi, which deevnet-kit made on the first boot from the
network make card asked for. A second address on the same network bought
nothing, appeared in the kit’s address warning, and could answer for
eds-backend.local.
After: the Pi has its cable alone, the Wi-Fi’s connection and key are gone
from it, and its radio is off and stays off. The next card is the same: the
image starts with the radio off, and make card asks for no network.
Procedure
Step 1: The Pi
Run, over SSH to the wired address: nmcli connection delete deevnet-kit-wifi, then nmcli radio wifi off.
Verify: the radio disabled, wlan0 unavailable, one address, and
WirelessEnabled=false in /var/lib/NetworkManager/NetworkManager.state.
Step 2: The next card
Change: images/backend/config.yml writes NetworkManager.state with
the radio off, and checks it at the end of the build; card.sh no longer
asks for a network; the README says the Pi is on a cable, and how to switch
Wi-Fi on by hand.
Verification
make status ok, the console answering, and eds-backend.local resolving
to 192.168.2.40 alone.
Undo
On the Pi: sudo nmcli radio wifi on and sudo nmcli --ask device wifi connect DVNT-CORE. For a card: revert this change’s commit.
Outcome
| When (UTC) | Step | What happened |
|---|---|---|
| 2026-10-30 02:16 | 1 | Over 192.168.2.40: deevnet-kit-wifi deleted, the radio off. wlan0 unavailable; one address; WirelessEnabled=false saved |
| 2026-10-30 02:16 | 1 | make status: every check ok. The console answered 200; eds-backend.local resolved to 192.168.2.40 alone |
| 2026-10-30 | 2 | The playbook parsed and passed Ansible’s syntax check; card.sh parsed. Not built: the Builder needs dvntm |
Departures from the plan
- None.
Follow-ups
- Build the image on a day on dvntm; its check reads the radio’s state back.