Backup VMs Using RBD

Script to backup VMs using RBD.

#!/bin/bash
# Configuration
POOL="vm_pool"
LOCAL_DIR="/mnt/ceph_backups"
REMOTE_USER="backupuser@remote-server"
REMOTE_BASE_DIR="/backups/ceph_vms"
COMPRESSION="zstd"
LOCAL_RETENTION=2
REMOTE_RETENTION=4
SSH_KEY="/root/.ssh/backup_key"

declare -A VM_DISKS=(
    [100]="vm-100-disk-0"
    [101]="vm-100-disk-0 vm-101-disk-1"  # Multi-disk VM example
    [102]="vm-102-disk-0"
)

# Create local directory
mkdir -p "$LOCAL_DIR"

for VMID in "${!VM_DISKS[@]}"; do
    DISK_LIST="${VM_DISKS[$VMID]}"
    TIMESTAMP=$(date +%Y%m%d-%H%M%S)
    REMOTE_VM_DIR="$REMOTE_BASE_DIR/vm$VMID"
    
    echo "Processing VM $VMID (disks: $DISK_LIST)"
    
    # Create remote directory
    ssh -i "$SSH_KEY" "$REMOTE_USER" "mkdir -p '$REMOTE_VM_DIR'"
    
    for DISK in $DISK_LIST; do
        BACKUP_FILE="$LOCAL_DIR/${DISK}_${TIMESTAMP}.img.$COMPRESSION"
        
        # Create snapshot (crash-consistent)
        SNAP_NAME="backup_$TIMESTAMP"
        rbd snap create "$POOL/$DISK@$SNAP_NAME"
        
        # Export snapshot to compressed file
        echo "Backing up $DISK..."
        rbd export "$POOL/$DISK@$SNAP_NAME" - | $COMPRESSION > "$BACKUP_FILE"
        
        # Remove temporary snapshot
        rbd snap rm "$POOL/$DISK@$SNAP_NAME"
        
        # Transfer to remote
        scp -i "$SSH_KEY" "$BACKUP_FILE" "$REMOTE_USER:$REMOTE_VM_DIR/"
        
        # Local cleanup
        ls -t "$LOCAL_DIR/${DISK}_"*".img.$COMPRESSION" 2>/dev/null | \
            tail -n +$(($LOCAL_RETENTION + 1)) | \
            xargs -r rm -f
        
        # Remote cleanup
        ssh -i "$SSH_KEY" "$REMOTE_USER" \
            "ls -t '$REMOTE_VM_DIR/${DISK}_'*'.img.$COMPRESSION' 2>/dev/null | \
             tail -n +$(($REMOTE_RETENTION + 1)) | \
             xargs -r rm -f"
    done
done

echo "Ceph RBD backup completed at $(date)"