Ryan Malloy
6881489bf6
What the Raspberry Pi time-server guides get wrong on a Pi 4, with the measurements. The headline artifact is a four-line pps-gpio patch: PREEMPT_RT force-threads IRQ handlers, and pps-gpio takes its timestamp inside its handler, so the realtime kernel puts a scheduler between the electrical edge and the clock. IRQF_NO_THREAD takes RMS offset from 2468 ns to 199 ns. - kernel/ the patch - dashboard/ live status page (position hidden by default) - docs-site/ the write-up (Astro/Starlight, brass, no tutorial section)
38 lines
1.3 KiB
Bash
38 lines
1.3 KiB
Bash
#!/usr/bin/env bash
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# Idempotent install/update of the gps-ntp dashboard. Run on the Pi as root
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# from the synced source tree (APPDIR). Safe to re-run.
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set -euo pipefail
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APPDIR="${APPDIR:-/opt/gpsntp-dashboard}"
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SVC=gpsntp-dashboard
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echo "==> dedicated system user"
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id -u gpsntp &>/dev/null || useradd --system --no-create-home --shell /usr/sbin/nologin gpsntp
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echo "==> python venv + editable install"
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if [ ! -x "$APPDIR/.venv/bin/python" ]; then
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if ! python3 -m venv "$APPDIR/.venv" 2>/dev/null; then
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apt-get update -qq && apt-get install -y python3-venv python3-pip
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python3 -m venv "$APPDIR/.venv"
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fi
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fi
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"$APPDIR/.venv/bin/pip" install --quiet --upgrade pip
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"$APPDIR/.venv/bin/pip" install --quiet -e "$APPDIR"
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echo "==> narrow sudoers rule (clients command only)"
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install -m 0440 "$APPDIR/deploy/gpsntp-dashboard.sudoers" /etc/sudoers.d/gpsntp-dashboard
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visudo -cf /etc/sudoers.d/gpsntp-dashboard
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echo "==> systemd unit"
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install -m 0644 "$APPDIR/deploy/gpsntp-dashboard.service" "/etc/systemd/system/${SVC}.service"
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echo "==> ownership"
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chown -R gpsntp:gpsntp "$APPDIR"
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echo "==> enable + (re)start"
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systemctl daemon-reload
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systemctl enable "${SVC}.service" >/dev/null 2>&1 || true
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systemctl restart "${SVC}.service"
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sleep 2
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systemctl is-active "${SVC}.service" && echo "==> dashboard active on :8080"
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