| name | boot-inspect |
| description | Inspect boot health on a systemd Linux system — failed units, slow services, kernel boot messages, and boot-to-boot comparison. Use when the user reports slow boot, services not starting, or wants to check post-reboot health. Targets Ubuntu/Debian + Wayland desktops but works on any systemd host. |
Boot Inspect
Systematic boot-time inspection. Run these in order; stop when you find the cause.
1. Failed units (the cheapest signal)
systemctl --failed --no-pager
For each failed unit, get its log:
journalctl -u <unit> -b --no-pager -p warning
Also check user-scope units (Wayland desktop session services often live here):
systemctl --user --failed --no-pager
2. Boot timing
systemd-analyze
systemd-analyze blame --no-pager | head -20
systemd-analyze critical-chain --no-pager
blame shows per-unit start time. critical-chain shows the dependency path that determined total boot time — fixing the slowest unit on the chain is what actually shortens boot.
3. Kernel ring buffer for this boot
dmesg --level=err,warn --ctime
journalctl -k -b -p warning --no-pager
Look for: firmware errors, ACPI warnings, GPU driver issues (especially relevant on Wayland — amdgpu/i915/nvidia messages), thermal events, USB errors.
4. Compare to previous boot
If a regression appeared after a recent reboot:
journalctl --list-boots --no-pager | head -10
journalctl -k -b -1 -p warning --no-pager > /tmp/prev-boot.log
journalctl -k -b 0 -p warning --no-pager > /tmp/curr-boot.log
diff /tmp/prev-boot.log /tmp/curr-boot.log
Requires persistent journald. If --list-boots only shows one entry, run validate-persistent-journal.
5. Display manager + Wayland session (desktop-specific)
For KDE Plasma on Wayland:
journalctl -u sddm -b --no-pager -p warning
journalctl --user -t plasmashell -b --no-pager -p warning
journalctl --user -t kwin_wayland -b --no-pager -p warning
For GNOME on Wayland:
journalctl -u gdm -b --no-pager -p warning
journalctl --user -t gnome-shell -b --no-pager -p warning
Reporting
Structure findings as:
- Boot time: total + slowest 3 units
- Failures: each failed unit with its key log line
- Kernel concerns: errors/warnings from dmesg, grouped by subsystem
- Regression vs previous boot: yes/no, and diff summary if yes
