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ImmortalWrt Smart Automatic Backup

Overview

This script set provides a stable daily backup workflow for ImmortalWrt routers:

  • Backup only when real config changes are detected
  • Keep both restore archives (.tar.gz) and extracted config snapshots
  • Push backup history to GitHub
  • Keep local/remote retention under control

Why This Approach

  • Avoid meaningless duplicate backups
  • Keep change history reviewable with Git diff
  • Make restore operations faster and more predictable
  • Reduce unnecessary SD card writes

Setup Steps

1. Install Dependencies

opkg update
opkg install git openssh-client openssh-keygen ca-bundle ca-certificates

2. Configure SSH Key

# Generate key if not exists
ssh-keygen -t ed25519 -f /root/.ssh/id_ed25519 -N ""

# Add the public key to GitHub
cat /root/.ssh/id_ed25519.pub

# Optional: force SSH over 443 (when port 22 is blocked)
cat > /root/.ssh/config <<'EOF'
Host github.com
  HostName ssh.github.com
  Port 443
  User git
  IdentityFile ~/.ssh/id_ed25519
  StrictHostKeyChecking accept-new
EOF

chmod 600 /root/.ssh/config
chmod 700 /root/.ssh
chmod 600 /root/.ssh/id_ed25519
chmod 644 /root/.ssh/id_ed25519.pub

# Connection test
ssh -T git@github.com

3. Deploy Backup Script

wget -O /root/smart_backup.sh https://raw.githubusercontent.com/YOUR_USERNAME/YOUR_REPO/master/scripts/smart_backup.sh
chmod +x /root/smart_backup.sh
vi /root/smart_backup.sh

Main config fields:

GIT_REMOTE="git@github.com:YOUR_USERNAME/YOUR_BACKUP_REPO.git"
BRANCH="master"
BACKUP_DIR="/root/immortalwrt-backup"
MAX_LOCAL_BACKUPS=3
MAX_REMOTE_BACKUPS=30

4. Configure Cron

# Run every day at 15:00
echo "0 15 * * * /root/smart_backup.sh >> /root/smart_backup.log 2>&1" >> /etc/crontabs/root
/etc/init.d/cron restart

5. Optional Boot Auto-Run

vi /etc/rc.local
# Add before exit 0:
/root/smart_backup.sh &
exit 0

Logs and Status

# Backup log
tail -n 50 /root/smart_backup.log

# Cron entries
crontab -l

# Manual test
/root/smart_backup.sh

Restore

1) Full Restore via .tar.gz

Use LuCI:

  • System -> Backup / Flash Firmware -> Restore backup

Or via CLI:

sysupgrade -r backup_YYYYMMDD_HHMMSS.tar.gz
reboot

2) Restore a Single Config File

If only one config is broken (for example network), copy the target file from repository configs/ and overwrite:

vi /etc/config/network
/etc/init.d/network restart

3) Review Change History

cd /root/immortalwrt-backup
git log --oneline configs/network
git show <commit>:configs/network

FAQ

Why no new backup was pushed?

The script skips backup when no effective config change is detected. This is expected behavior.

Push failed (network/SSH)?

Check:

  • SSH key and ~/.ssh/config
  • connectivity to GitHub (ssh -T git@github.com)
  • repository permissions and remote URL

Can I force a backup?

Yes, run manually:

/root/smart_backup.sh