When executing shutdown now in a Debian terminal, you might encounter this sequence:

All processes ended within 2 seconds...done
INIT: Going single user
INIT: Sending processes the TERM signal
INIT: Sending processes the KILL signal
Give root password for maintenance(or...

This typically indicates one or more processes are refusing to terminate properly during shutdown. The system switches to single-user mode as a failsafe. Common culprits include:

• Network time protocol daemons (ntpd)
• Custom iptables rules
• Unresponsive hardware drivers
• Filesystem sync issues

To identify the problematic process, check system logs:

journalctl -b -1 | grep -i "fail\|error\|warn\|terminat"
dmesg | tail -n 50
cat /var/log/syslog | grep -i shutdown

If you suspect ntp/ntpdate conflicts, try these steps:

# Stop ntp services before shutdown
sudo systemctl stop ntp
sudo systemctl stop ntpdate

# Alternatively, modify the service file
sudo nano /lib/systemd/system/ntp.service
# Add under [Service]:
TimeoutStopSec=5
KillMode=process

For iptables-related shutdown hangs:

# Create a pre-shutdown flush script
sudo nano /etc/init.d/flush-iptables
#!/bin/sh
### BEGIN INIT INFO
# Provides:          flush-iptables
# Required-Start:
# Required-Stop:     $local_fs $network
# Default-Start:
# Default-Stop:      0 6
# Short-Description: Flush iptables before shutdown
### END INIT INFO

case "$1" in
    stop)
        iptables -F
        iptables -X
        iptables -t nat -F
        iptables -t nat -X
        ;;
esac

exit 0

# Make executable and register
sudo chmod +x /etc/init.d/flush-iptables
sudo update-rc.d flush-iptables defaults

When regular shutdown fails, try these commands:

# Force immediate shutdown
sudo shutdown -h now

# Poweroff directly
sudo poweroff

# Emergency fallback
echo 1 > /proc/sys/kernel/sysrq
echo o > /proc/sysrq-trigger

Modify systemd shutdown behavior:

sudo nano /etc/systemd/system.conf
# Adjust these values:
DefaultTimeoutStartSec=10s
DefaultTimeoutStopSec=10s

After changes, reload systemd:

sudo systemctl daemon-reload

Verify the fix works by simulating shutdown:

sudo systemctl start emergency.target
# Check which services remain
systemctl list-units --state=failed

---

When executing shutdown now in a terminal, the system should cleanly terminate all processes. The output you're seeing indicates an abnormal shutdown sequence:

All processes ended within 2 seconds...done
INIT: Going single user
INIT: Sending processes the TERM signal
INIT: Sending processes the KILL signal
Give root password for maintenance(or...

The root password prompt during shutdown typically appears when:

• A critical process fails to terminate properly
• Filesystem unmount operations hang
• Network services don't release resources
• Hardware drivers misbehave during power-off

Given you recently installed NTP services, we should investigate potential conflicts:

# Check running NTP processes before shutdown
ps aux | grep ntp

# Verify service shutdown behavior
systemctl status ntp.service
journalctl -u ntp.service --no-pager

Create a shutdown debug script (/usr/local/bin/shutdown-debug):

#!/bin/bash
echo "Starting shutdown debug..."
exec > /var/log/shutdown-debug.log 2>&1
date
ps auxf
lsof
systemctl list-units --state=running
echo "Debug information captured"

Make it executable and trigger before shutdown:

chmod +x /usr/local/bin/shutdown-debug
shutdown -c "Debugging shutdown" /usr/local/bin/shutdown-debug

For NTP-related issues:

# Modify NTP service to ensure clean shutdown
sudo systemctl edit ntpd.service

[Service]
TimeoutStopSec=5
KillMode=process
ExecStop=/usr/sbin/ntpd -q -g -x -N

General systemd troubleshooting:

# Increase systemd shutdown timeout
sudo mkdir -p /etc/systemd/system.conf.d
echo -e "[Manager]\nDefaultTimeoutStopSec=10s" | sudo tee /etc/systemd/system.conf.d/timeout.conf
systemctl daemon-reload

For persistent cases, enable verbose shutdown logging:

# Edit kernel parameters
sudo sed -i 's/GRUB_CMDLINE_LINUX_DEFAULT="/&initcall_debug log_buf_len=16M /' /etc/default/grub
sudo update-grub

After reproducing the issue, check kernel logs with:

dmesg | grep -iE 'shutdown|terminat|hang|blocked'