Custom Routing mit Cloud-Init in Proxmox: Ein praktischer Leitfaden

#!/bin/bash

# Script to add static routes to Cloud-Init configuration for a Proxmox VM
# Usage: ./add_static_route.sh VMID NETWORK GATEWAY [DESCRIPTION]
# Example: ./add_static_route.sh 100 192.168.10.0/24 10.0.0.1 "Route to internal network"

set -e

# Check if required parameters are provided
if [ $# -lt 3 ]; then
    echo "Usage: $0 VMID NETWORK GATEWAY [DESCRIPTION]"
    echo "Example: $0 100 192.168.10.0/24 10.0.0.1 \"Route to internal network\""
    exit 1
fi

VMID=$1
NETWORK=$2
GATEWAY=$3
DESCRIPTION=${4:-"Custom static route"}

# Verify that the VM exists
if ! qm status $VMID &>/dev/null; then
    echo "Error: VM with ID $VMID does not exist"
    exit 1
fi

# Check if the VM has cloud-init configured (on any IDE/SCSI device)
if ! qm config $VMID | grep -E "(ide|scsi)[0-9].*cloudinit" > /dev/null; then
    echo "Error: VM $VMID does not have Cloud-Init configured (no cloudinit drive found)"
    exit 1
fi

# Create a temporary directory for our work
TEMP_DIR=$(mktemp -d)
trap 'rm -rf "$TEMP_DIR"' EXIT

# Get current network cloud-init config
echo "Dumping current Cloud-Init network configuration..."
if ! qm cloudinit dump $VMID network > "$TEMP_DIR/network_original.yaml" 2>/dev/null; then
    echo "Info: No existing network configuration found, creating new one"
    # Create a basic network config structure if none exists
    cat > "$TEMP_DIR/network_original.yaml" << EOF
version: 2
ethernets:
  eth0:
    dhcp4: true
EOF
fi

# Make a backup of the original configuration
cp "$TEMP_DIR/network_original.yaml" "$TEMP_DIR/network_original.yaml.bak"

# Create a modified network configuration
echo "Creating modified configuration with static route..."
cp "$TEMP_DIR/network_original.yaml" "$TEMP_DIR/network_modified.yaml"

# Determine network configuration version
VERSION=$(grep -m 1 "version:" "$TEMP_DIR/network_original.yaml" | awk '{print $2}')
echo "Detected network configuration version: $VERSION"

if [ "$VERSION" = "1" ]; then
    # For version 1, we need to carefully modify the config to maintain proper indentation
    # First, let's create a new file with the correct structure
    cp "$TEMP_DIR/network_modified.yaml" "$TEMP_DIR/network_modified.yaml.tmp"
    
    # Find the physical section with eth0
    ETH0_SECTION=$(grep -n "name: eth0" "$TEMP_DIR/network_modified.yaml.tmp" | cut -d: -f1)
    if [ -z "$ETH0_SECTION" ]; then
        echo "Error: Could not find eth0 section"
        exit 1
    fi
    
    # Create a new file with the corrected format
    echo "version: 1" > "$TEMP_DIR/network_modified.yaml"
    echo "config:" >> "$TEMP_DIR/network_modified.yaml"
    
    # Process the file line by line with correct indentation
    FOUND_ETH0=false
    ADDED_ROUTES=false
    SUBNETS_SECTION=false
    
    while IFS= read -r line; do
        # Skip the version and config lines as we've already added them
        if [[ "$line" == "version: 1" || "$line" == "config:" ]]; then
            continue
        fi
        
        # Check if we're in the eth0 section
        if [[ "$line" == *"name: eth0"* ]]; then
            FOUND_ETH0=true
        fi
        
        # Check if we're in the subnets section 
        if [[ "$FOUND_ETH0" == true && "$line" == *"subnets:"* ]]; then
            SUBNETS_SECTION=true
        fi
        
        # Add the routes after the last subnet entry
        if [[ "$SUBNETS_SECTION" == true && "$line" == *"gateway:"* && "$ADDED_ROUTES" == false ]]; then
            echo "$line" >> "$TEMP_DIR/network_modified.yaml"
            echo "        routes:" >> "$TEMP_DIR/network_modified.yaml"
            echo "          - network: $NETWORK" >> "$TEMP_DIR/network_modified.yaml"
            echo "            gateway: $GATEWAY" >> "$TEMP_DIR/network_modified.yaml"
            ADDED_ROUTES=true
            continue
        fi
        
        # Add the line to the new file
        echo "$line" >> "$TEMP_DIR/network_modified.yaml"
        
    done < "$TEMP_DIR/network_modified.yaml.tmp"
    
    # If we didn't find a place to add routes, report an error
    if [[ "$ADDED_ROUTES" == false ]]; then
        echo "Error: Could not find an appropriate place to add routes"
        echo "Please manually modify the cloud-init configuration"
        exit 1
    fi
elif [ "$VERSION" = "2" ]; then
    # Check if the eth0 interface exists
    if ! grep -q "eth0:" "$TEMP_DIR/network_modified.yaml"; then
        echo "Error: Version 2 network configuration doesn't contain eth0 section"
        cat "$TEMP_DIR/network_original.yaml"
        exit 1
    fi
    
    # Check if routes section already exists
    if grep -q "routes:" "$TEMP_DIR/network_modified.yaml"; then
        # Add route to existing routes section
        sed -i "/routes:/a\\        - to: $NETWORK\\n          via: $GATEWAY\\n          # $DESCRIPTION" "$TEMP_DIR/network_modified.yaml"
    else
        # Add routes section after eth0
        sed -i "/eth0:/a\\      routes:\\n        - to: $NETWORK\\n          via: $GATEWAY\\n          # $DESCRIPTION" "$TEMP_DIR/network_modified.yaml"
    fi
else
    echo "Error: Unsupported network configuration version: $VERSION"
    cat "$TEMP_DIR/network_original.yaml"
    exit 1
fi

# Save the modified configuration to a snippets directory
SNIPPET_NAME="vm-${VMID}-custom-network-$(date +%s).yaml"
SNIPPETS_PATH="/var/lib/vz/snippets"

# Ensure snippets directory exists
if [ ! -d "$SNIPPETS_PATH" ]; then
    echo "Creating snippets directory at $SNIPPETS_PATH"
    mkdir -p "$SNIPPETS_PATH"
fi

# Create backup of original config
BACKUP_NAME="vm-${VMID}-network-backup-$(date +%s).yaml"
cp "$TEMP_DIR/network_original.yaml" "$SNIPPETS_PATH/$BACKUP_NAME"
echo "Original configuration backed up to $SNIPPETS_PATH/$BACKUP_NAME"

# Show differences between original and modified configuration
echo -e "\nConfiguration changes:"
diff -u "$TEMP_DIR/network_original.yaml" "$TEMP_DIR/network_modified.yaml" || true

# Ask for confirmation before applying changes
echo -e "\nReady to apply the new network configuration to VM $VMID."
echo "Do you want to continue? (y/N)"
read -r confirm
if [[ ! "$confirm" =~ ^[Yy]$ ]]; then
    echo "Operation cancelled by user."
    exit 0
fi

# Copy the modified configuration to snippets
cp "$TEMP_DIR/network_modified.yaml" "$SNIPPETS_PATH/$SNIPPET_NAME"
echo "Saved modified network configuration to $SNIPPETS_PATH/$SNIPPET_NAME"

# Set the custom network configuration for the VM
echo "Applying custom network configuration to VM $VMID..."
qm set $VMID --cicustom "network=local:snippets/$SNIPPET_NAME"

# Show the final configuration
echo -e "\nFinal Cloud-Init network configuration for VM $VMID:"
qm cloudinit dump $VMID network

echo -e "\nStatic route added successfully to VM $VMID"
echo "Network: $NETWORK"
echo "Gateway: $GATEWAY"
echo "Description: $DESCRIPTION"
echo -e "\nCustom configuration stored in: $SNIPPETS_PATH/$SNIPPET_NAME"
echo -e "Backup stored in: $SNIPPETS_PATH/$BACKUP_NAME"
echo -e "\nTo restore the original configuration if needed, run:"
echo "qm set $VMID --cicustom \"network=local:snippets/$BACKUP_NAME\""

version: 1
config:
  - type: physical
    name: eth0
    subnets:
      - type: static
        address: '10.0.0.2'
        netmask: '255.255.255.0'
        gateway: '10.0.0.1'
        routes:
          - network: '192.168.0.0/24'
            gateway: '10.0.0.254'

version: 2
ethernets:
  eth0:
    addresses: ['10.0.0.2/24']
    gateway4: '10.0.0.1'
    routes:
      - to: '192.168.0.0/24'
        via: '10.0.0.254'

chmod +x add_static_route.sh
./add_static_route.sh 100 192.168.10.0/24 10.0.0.1 "Route zu internem Netzwerk"