auto-updates（自动更新）

Auto Updates Skill

Enable automatic security updates on VPS servers to ensure systems are patched against known vulnerabilities.

What This Skill Does

This skill helps AI agents configure automatic security updates on Ubuntu/Debian-based VPS servers. Every piece of software has vulnerabilities - patches fix them. If you're not patching, you're running known-vulnerable software that attackers have pre-built exploits for.

Key capabilities:

• Update package lists and upgrade installed packages
• Configure unattended-upgrades for automatic security patches
• Set up automatic reboot schedules when required
• Verify update configuration and status

When to Use

Use this skill when you need to:

• Set up a new VPS server with automatic updates
• Harden an existing server against known vulnerabilities
• Ensure compliance with security patching requirements
• Reduce manual maintenance overhead
• Fix security audit findings related to outdated packages

Critical understanding: A server that's been up for 400 days isn't impressive - it's concerning. Regular updates and reboots are essential for security.

Prerequisites

• Root or sudo access to the server
• Ubuntu or Debian-based Linux distribution
• Internet connectivity for package downloads
• SSH access to the server

Installation & Configuration

Step 1: Update System Packages

First, update the package list and upgrade all installed packages:

sudo apt update && sudo apt upgrade -y

What this does:

• apt update - Refreshes the package index from repositories
• apt upgrade -y - Installs available updates without prompting

Step 2: Install Unattended Upgrades

Install the unattended-upgrades package:

sudo apt install unattended-upgrades -y

Step 3: Configure Unattended Upgrades

Enable automatic updates using the configuration tool:

sudo dpkg-reconfigure unattended-upgrades

Select "Yes" when prompted to enable automatic updates.

Alternative manual configuration:

Edit /etc/apt/apt.conf.d/50unattended-upgrades to customize:

sudo nano /etc/apt/apt.conf.d/50unattended-upgrades

Key settings to review:

• Unattended-Upgrade::Allowed-Origins - Which updates to install
• Unattended-Upgrade::Automatic-Reboot - Auto-reboot if required (default: false)
• Unattended-Upgrade::Automatic-Reboot-Time - When to reboot (e.g., "02:00")
• Unattended-Upgrade::Remove-Unused-Dependencies - Clean up old packages

Step 4: Verify Configuration

Check that unattended-upgrades is active:

sudo systemctl status unattended-upgrades

View the automatic upgrade log:

sudo cat /var/log/unattended-upgrades/unattended-upgrades.log

Configuration Options

Automatic Reboot Settings

To enable automatic reboots when kernel updates require them, edit /etc/apt/apt.conf.d/50unattended-upgrades:

Unattended-Upgrade::Automatic-Reboot "true";
Unattended-Upgrade::Automatic-Reboot-Time "02:00";

Update Frequency

The default update frequency is configured in /etc/apt/apt.conf.d/20auto-upgrades:

APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Unattended-Upgrade "1";
APT::Periodic::Download-Upgradeable-Packages "1";
APT::Periodic::AutocleanInterval "7";

Testing

Perform a dry run to see what would be updated:

sudo unattended-upgrade --dry-run --debug

Manually trigger an update cycle:

sudo unattended-upgrade --debug

Troubleshooting

Updates Not Running

Check the systemd timer status:

sudo systemctl status apt-daily.timer
sudo systemctl status apt-daily-upgrade.timer

Enable timers if disabled:

sudo systemctl enable apt-daily.timer
sudo systemctl enable apt-daily-upgrade.timer

Check Logs

View recent update activity:

sudo journalctl -u unattended-upgrades

Held Packages

Some packages may be held back. List them:

apt-mark showhold

Unhold if safe:

sudo apt-mark unhold <package-name>

Security Best Practices

1. Enable automatic security updates - Don't wait for manual intervention
2. Monitor update logs - Regularly review /var/log/unattended-upgrades/
3. Plan for reboots - Some updates require system restart
4. Test in staging - For production systems, test updates in a staging environment first
5. Set up monitoring - Alert on failed updates or long uptime without reboots

Common Mistakes to Avoid

• ❌ Disabling updates because "they might break something"
• ❌ Not monitoring update logs for failures
• ❌ Ignoring reboot notifications for kernel updates
• ❌ Holding back security packages indefinitely

Additional Resources

See references/apt-config.md for detailed APT configuration options.

See scripts/setup-auto-updates.sh for automated setup script.

Related Skills

• ssh-hardening - Secure SSH configuration
• firewall-configuration - Set up UFW firewall
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