Ubuntu 16.04 LTS开机及关机发送邮件的实现方案求助

Since you’ve already tried crontab @reboot, init.d scripts, and rc.local without luck, let’s dive into systemd-specific fixes and desktop-environment quirks that might be blocking your email alerts. Here are actionable troubleshooting steps:

1. Switch to Systemd Services (The Modern Ubuntu Way) #

Ubuntu desktop uses systemd by default, so sysvinit-style init.d scripts can run into execution order or environment issues. Create separate services for boot and shutdown:

Boot Email Service #

Create a file at /etc/systemd/system/boot-mail.service with this content:

[Unit]
Description=Send email on system boot
After=network.target network-online.target
Wants=network-online.target

[Service]
Type=oneshot
ExecStart=/path/to/your/boot-script.sh
User=root
StandardOutput=journal+console

[Install]
WantedBy=multi-user.target

• After=network.target ensures the script runs only after the network is up (critical for sending emails)
• Reload systemd and enable the service:

  sudo systemctl daemon-reload
  sudo systemctl enable boot-mail.service
  

Shutdown Email Service #

Shutdown requires special handling because systemd terminates processes quickly. Create /etc/systemd/system/shutdown-mail.service:

[Unit]
Description=Send email on system shutdown
DefaultDependencies=no
Before=shutdown.target reboot.target halt.target

[Service]
Type=oneshot
ExecStart=/bin/true  # Dummy start command to satisfy systemd
ExecStop=/path/to/your/shutdown-script.sh
TimeoutStopSec=30  # Give enough time to send the email
User=root

[Install]
WantedBy=shutdown.target reboot.target halt.target

Enable it with the same daemon-reload and enable commands above.

Check service status for errors with:

sudo systemctl status boot-mail.service
sudo systemctl status shutdown-mail.service

2. Validate Script Execution Environment #

Boot/shutdown runs in a minimal, non-interactive environment—your script might fail due to missing paths or variables:

• Use absolute paths for all commands in your script (e.g., /usr/bin/mail instead of just mail)
• Test the script as root in a non-interactive shell to replicate boot conditions:

  sudo -i bash -c '/path/to/your/script.sh'
  

• Add logging to your script to capture errors:

  echo "Boot attempt at $(date):" >> /var/log/boot-shutdown-mail.log 2>&1
  /usr/bin/mail -s "System Booted" your@email.com < /dev/null >> /var/log/boot-shutdown-mail.log 2>&1
  

Check the log with tail /var/log/boot-shutdown-mail.log to spot failures.

3. Account for Ubuntu Desktop Network Delays #

Desktop editions often take longer to establish a network connection than server editions. If your boot script runs before the network is ready:

• Add a delay to your crontab @reboot entry (if you still want to use it):

  @reboot sleep 60 && /path/to/your/boot-script.sh
  

• Or rely on systemd’s network-online.target (already included in the boot service above) to wait for a fully connected network.

4. Verify Email Configuration #

Double-check that your mail setup works outside of boot/shutdown:

• Test sending a manual email as root:

  echo "Test message" | /usr/bin/mail -s "Test Email" your@email.com
  

• Check mail logs for errors:

  tail -f /var/log/mail.log
  

Look for entries like authentication failures or SMTP connection timeouts—these indicate a problem with your mailutils/sendmail config, not the boot/shutdown trigger.

5. Ensure rc.local is Enabled (If You Prefer It) #

Modern Ubuntu disables rc.local by default. To use it:

• Check if the service is active:

  systemctl status rc-local.service
  

• If inactive, enable it:

  sudo systemctl enable rc-local.service
  

• Make sure /etc/rc.local has the correct shebang (#!/bin/bash) at the top, execution permissions (chmod +x /etc/rc.local), and ends with exit 0.

内容的提问来源于stack exchange，提问作者Alex R.