# Business Central SaaS Automated Backup System

Comprehensive backup solution for Microsoft Dynamics 365 Business Central SaaS that:
- Exports database via BC Admin Center API every hour
- Encrypts backups with GPG (AES-256)
- Uploads to S3-compatible object storage
- Enables immutability with 30-day delete prevention
- Maintains timestamped backup history

## Features

- **Automated Hourly Backups**: Uses cron/systemd to run backups on schedule
- **Secure Encryption**: GPG encryption with AES-256 cipher
- **Immutable Storage**: S3 Object Lock (WORM) with 30-day retention
- **Multiple S3 Providers**: AWS S3, MinIO, Wasabi, Backblaze B2
- **Comprehensive Logging**: Detailed logs for troubleshooting
- **Error Handling**: Retries and proper error reporting
- **Clean Architecture**: Modular bash + PowerShell scripts

## Architecture

```
┌─────────────────────┐
│   Cron/Systemd      │
│   (Hourly Trigger)  │
└──────────┬──────────┘
           │
           ▼
┌─────────────────────┐
│   bc-backup.sh      │ ◄─── Main orchestration script (bash)
│   - Orchestrates    │
│   - Encryption      │
│   - S3 Upload       │
└──────────┬──────────┘
           │
           ▼
┌─────────────────────┐
│   bc-export.ps1     │ ◄─── BC export logic (PowerShell)
│   - Azure AD auth   │
│   - API calls       │
│   - Download BACPAC │
└──────────┬──────────┘
           │
           ▼
┌─────────────────────┐
│   BC Admin API      │
│   (Microsoft)       │
└─────────────────────┘
```

## Prerequisites

### 1. System Requirements

- **Linux server** (Ubuntu 20.04+, Debian 10+, CentOS 7+, or similar)
- **PowerShell 7+** (installed automatically by setup script)
- **GPG** (for encryption)
- **AWS CLI v2** or **s3cmd** (for S3 uploads)
- **Root or sudo access** (for initial setup)

### 2. Business Central Requirements

- Active Business Central SaaS subscription (paid, not trial)
- Production environment (exports only available from Production)
- Admin access to BC Admin Center

### 3. Azure AD App Registration

You need an Azure AD application with API permissions to access BC Admin Center API.

### 4. S3-Compatible Storage

- S3 bucket with **Object Lock enabled** (immutability)
- Access credentials (Access Key ID + Secret Access Key)

## Quick Start

### 1. Download and Setup

```bash
cd /home/malin/c0ding/bcbak
chmod +x setup.sh
./setup.sh
```

The setup script will:
- Check and install dependencies (PowerShell, GPG, AWS CLI)
- Create directory structure
- Copy configuration template
- Set proper permissions

### 2. Create Azure AD App Registration

#### Step-by-Step:

1. Navigate to [Azure Portal](https://portal.azure.com)
2. Go to **Azure Active Directory** > **App registrations** > **New registration**
3. Configure:
   - **Name**: `BC-Backup-Service`
   - **Supported account types**: Accounts in this organizational directory only
   - **Redirect URI**: Leave empty
4. Click **Register**
5. Note the following from the Overview page:
   - **Application (client) ID**
   - **Directory (tenant) ID**

#### Create Client Secret:

1. Go to **Certificates & secrets** > **New client secret**
2. **Description**: `BC Backup Key`
3. **Expires**: Choose appropriate duration (6 months, 1 year, etc.)
4. Click **Add**
5. **Copy the secret value immediately** (shown only once!)

#### Add API Permissions:

1. Go to **API permissions** > **Add a permission**
2. Select **Dynamics 365 Business Central**
3. Choose **Application permissions** (not Delegated)
4. Select: `Automation.ReadWrite.All` or `API.ReadWrite.All`
5. Click **Add permissions**
6. **Important**: Click **Grant admin consent for [Your Organization]**
   - Requires Global Administrator role

### 3. Configure S3 Bucket with Object Lock

#### AWS S3 Example:

```bash
# Create bucket with Object Lock enabled
aws s3api create-bucket \
  --bucket my-bc-backups \
  --region us-east-1 \
  --object-lock-enabled-for-bucket

# Configure default retention (30 days, COMPLIANCE mode)
aws s3api put-object-lock-configuration \
  --bucket my-bc-backups \
  --object-lock-configuration '{
    "ObjectLockEnabled": "Enabled",
    "Rule": {
      "DefaultRetention": {
        "Mode": "COMPLIANCE",
        "Days": 30
      }
    }
  }'
```

#### MinIO Example:

```bash
# Create bucket
mc mb myminio/my-bc-backups --with-lock

# Set retention
mc retention set --default COMPLIANCE "30d" myminio/my-bc-backups
```

**Important**: Object Lock can **only be enabled when creating a bucket**. You cannot add it to existing buckets.

### 4. Configure the Backup System

Edit the configuration file:

```bash
nano bc-backup.conf
```

Fill in the required values:

```bash
# Azure AD Configuration
AZURE_TENANT_ID="your-tenant-id-here"
AZURE_CLIENT_ID="your-client-id-here"
AZURE_CLIENT_SECRET="your-client-secret-here"

# Business Central
BC_ENVIRONMENT_NAME="Production"

# Generate a strong encryption passphrase
ENCRYPTION_PASSPHRASE="$(openssl rand -base64 32)"

# S3 Configuration
S3_BUCKET="my-bc-backups"
S3_ENDPOINT="https://s3.amazonaws.com"  # or your S3 provider
AWS_ACCESS_KEY_ID="your-access-key"
AWS_SECRET_ACCESS_KEY="your-secret-key"
AWS_DEFAULT_REGION="us-east-1"

# Backup settings
RETENTION_DAYS="30"
S3_TOOL="awscli"
CLEANUP_LOCAL="true"
```

**Security**: Store your `ENCRYPTION_PASSPHRASE` securely in a password manager!

### 5. Test Manual Backup

Run a test backup:

```bash
./bc-backup.sh
```

Monitor the logs:

```bash
tail -f logs/backup.log
```

Expected output:
```
[2026-01-07 10:00:00] =========================================
[2026-01-07 10:00:00] Starting Business Central backup process
[2026-01-07 10:00:00] =========================================
[2026-01-07 10:00:00] Environment: Production
[2026-01-07 10:00:00] S3 Bucket: my-bc-backups
[2026-01-07 10:00:00] Retention: 30 days
[2026-01-07 10:00:01] Step 1: Initiating database export via BC Admin Center API
...
```

### 6. Set Up Automated Hourly Backups

#### Option A: Using Cron (Simpler)

```bash
crontab -e
```

Add this line for hourly backups:
```
0 * * * * /home/malin/c0ding/bcbak/bc-backup.sh >> /home/malin/c0ding/bcbak/logs/cron.log 2>&1
```

See `cron-examples.txt` for more scheduling options.

#### Option B: Using Systemd Timers (More Reliable)

Create service file:
```bash
sudo nano /etc/systemd/system/bc-backup.service
```

```ini
[Unit]
Description=Business Central Database Backup

[Service]
Type=oneshot
User=malin
WorkingDirectory=/home/malin/c0ding/bcbak
ExecStart=/home/malin/c0ding/bcbak/bc-backup.sh
StandardOutput=append:/home/malin/c0ding/bcbak/logs/backup.log
StandardError=append:/home/malin/c0ding/bcbak/logs/backup.log
```

Create timer file:
```bash
sudo nano /etc/systemd/system/bc-backup.timer
```

```ini
[Unit]
Description=Run BC Backup Every Hour

[Timer]
OnCalendar=hourly
Persistent=true

[Install]
WantedBy=timers.target
```

Enable and start:
```bash
sudo systemctl daemon-reload
sudo systemctl enable bc-backup.timer
sudo systemctl start bc-backup.timer
sudo systemctl status bc-backup.timer
```

## File Structure

```
bcbak/
├── bc-backup.sh              # Main orchestration script
├── bc-export.ps1             # PowerShell BC export logic
├── bc-backup.conf            # Your configuration (gitignored)
├── bc-backup.conf.template   # Configuration template
├── setup.sh                  # Installation script
├── cron-examples.txt         # Cron scheduling examples
├── README.md                 # This file
├── logs/                     # Backup logs
│   ├── backup.log
│   └── cron.log
└── temp/                     # Temporary files (auto-cleaned)
    └── bc_backup_*.bacpac
```

## How It Works

### 1. Database Export (bc-export.ps1)

- Authenticates to Azure AD using client credentials (OAuth 2.0)
- Calls BC Admin Center API to initiate database export
- Polls for completion (exports can take 15-60 minutes)
- Downloads BACPAC file to local temp directory

### 2. Encryption (bc-backup.sh)

- Uses GPG with AES-256 symmetric encryption
- Encrypts the BACPAC file with your passphrase
- Original unencrypted file is deleted

### 3. Upload to S3

- Uploads encrypted file with timestamp in filename
- Format: `backups/bc_backup_Production_20260107_100000.bacpac.gpg`
- Sets Object Lock retention (COMPLIANCE mode, 30 days)
- Files are **immutable** and **cannot be deleted** until retention expires

### 4. Verification & Cleanup

- Verifies upload success
- Removes local encrypted file (optional)
- Logs all operations

## Restoring from Backup

### 1. Download Encrypted Backup

```bash
# Using AWS CLI
aws s3 cp \
  s3://my-bc-backups/backups/bc_backup_Production_20260107_100000.bacpac.gpg \
  ./backup.bacpac.gpg \
  --endpoint-url https://s3.amazonaws.com
```

### 2. Decrypt the Backup

```bash
# Enter your ENCRYPTION_PASSPHRASE when prompted
gpg --decrypt backup.bacpac.gpg > backup.bacpac
```

### 3. Restore to Azure SQL Database

```bash
# Using SqlPackage (download from Microsoft)
sqlpackage /a:Import \
  /sf:backup.bacpac \
  /tsn:your-server.database.windows.net \
  /tdn:RestoredDatabase \
  /tu:admin \
  /tp:password
```

### 4. Connect BC to Restored Database

Contact Microsoft Support to point your BC environment to the restored database.

## Monitoring and Maintenance

### Check Backup Logs

```bash
# View latest backup log
tail -100 logs/backup.log

# Follow live log
tail -f logs/backup.log

# Check for errors
grep ERROR logs/backup.log
```

### List S3 Backups

```bash
# AWS CLI
aws s3 ls s3://my-bc-backups/backups/ --endpoint-url https://s3.amazonaws.com

# s3cmd
s3cmd ls s3://my-bc-backups/backups/
```

### Check Object Lock Status

```bash
aws s3api get-object-retention \
  --bucket my-bc-backups \
  --key backups/bc_backup_Production_20260107_100000.bacpac.gpg \
  --endpoint-url https://s3.amazonaws.com
```

### Verify Cron/Timer Status

```bash
# Cron
crontab -l
grep CRON /var/log/syslog | tail

# Systemd
systemctl status bc-backup.timer
journalctl -u bc-backup.service -n 50
```

## Troubleshooting

### Issue: "Authentication failed"

**Solution**: Verify Azure AD credentials
- Check `AZURE_TENANT_ID`, `AZURE_CLIENT_ID`, `AZURE_CLIENT_SECRET`
- Verify API permissions are granted with admin consent
- Ensure client secret hasn't expired

### Issue: "Database export failed - not authorized"

**Causes**:
- Only Production environments can be exported
- Trial subscriptions don't support exports
- Missing API permissions

**Solution**: Verify environment is Production with paid subscription

### Issue: "Export timeout exceeded"

**Solution**: Increase timeout
```bash
# In bc-backup.conf
MAX_EXPORT_WAIT_MINUTES="180"  # 3 hours
```

### Issue: "Object lock not supported"

**Solution**: Recreate bucket with Object Lock
- Object Lock can only be enabled at bucket creation
- Migrate existing backups to new bucket

### Issue: "Upload failed - access denied"

**Solution**: Check S3 credentials and permissions
```bash
# Test AWS CLI configuration
aws s3 ls --endpoint-url https://s3.amazonaws.com

# Verify bucket policy allows PutObject and PutObjectRetention
```

### Issue: "Decryption failed"

**Solution**: Verify encryption passphrase
- Ensure you're using the correct `ENCRYPTION_PASSPHRASE`
- Check for special characters that might need escaping

## Security Best Practices

1. **Protect Configuration File**
   - Set proper permissions: `chmod 600 bc-backup.conf`
   - Never commit to version control (use `.gitignore`)

2. **Rotate Credentials Regularly**
   - Azure AD client secrets (every 6-12 months)
   - S3 access keys (annually)
   - Encryption passphrase (when staff changes)

3. **Use Separate Service Account**
   - Create dedicated Linux user for backups
   - Run with minimal permissions

4. **Encryption Key Management**
   - Store `ENCRYPTION_PASSPHRASE` in password manager
   - Document in secure runbook
   - Test decryption regularly

5. **Monitor for Failures**
   - Set up log monitoring/alerting
   - Test restore process monthly

6. **Network Security**
   - Use HTTPS for S3 endpoints
   - Consider VPN for sensitive environments

## Limitations

1. **BC API Limits**
   - Maximum 10 database exports per month (Microsoft limit)
   - This script tracks recent exports to avoid unnecessary duplicates

2. **Export Restrictions**
   - Only Production environments
   - Only paid subscriptions
   - Exports can take 15-60 minutes

3. **Object Lock Immutability**
   - Files cannot be deleted until retention expires
   - Ensure adequate S3 storage capacity
   - Plan for storage costs

4. **Bandwidth**
   - Large databases require significant bandwidth
   - Consider S3 transfer costs

## Cost Considerations

### S3 Storage Costs (Example: AWS)

For a 50GB database with hourly backups:
- **Storage**: ~50GB × 720 backups (30 days) = 36TB × $0.023/GB = ~$830/month
- **Uploads**: 720 requests × $0.005/1000 = ~$0.004/month
- **Data Transfer Out** (for restores): $0.09/GB

**Recommendation**: Consider daily backups instead of hourly to reduce costs.

### Optimization Strategies

1. **Reduce Frequency**: Daily or every 6 hours instead of hourly
2. **Lifecycle Policies**: Move older backups to cheaper storage tiers
3. **Incremental Backups**: Consider BC's built-in continuous backup for point-in-time recovery

## Support and Contributing

### Getting Help

1. Check logs: `logs/backup.log`
2. Review troubleshooting section above
3. Check BC Admin Center for export status
4. Verify S3 bucket configuration

### Reporting Issues

When reporting issues, include:
- Relevant log excerpts
- BC environment type (Production/Sandbox)
- S3 provider (AWS/MinIO/etc.)
- Error messages

## License

This backup solution is provided as-is without warranty. Use at your own risk.

## References

- [BC Admin Center API Documentation](https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/administration/administration-center-api)
- [BC Data Extraction](https://github.com/microsoft/BCTech/tree/master/samples/ExtractData)
- [AWS S3 Object Lock](https://docs.aws.amazon.com/AmazonS3/latest/userguide/object-lock.html)
- [GPG Documentation](https://gnupg.org/documentation/)

## Changelog

### v1.0.0 (2026-01-07)
- Initial release
- Hourly automated backups
- GPG encryption with AES-256
- S3 Object Lock support
- AWS CLI and s3cmd support
- Comprehensive logging