Debian: Configuring VMware VM Customization Specifications for Debian GNU/Linux OS

Unfortunately, when using "VM Customization Specifications" to deploy Debian OS, the "open-vm-tools" scripts cannot correctly configure certain parameters for this system. To solve this issue, we'll use a custom script that will handle the functionality that doesn't work properly in the tools themselves.

Execute the following steps to configure "VM Customization Specifications":

1. Prepare a Debian OS template with the necessary software that should already be included with new hosts.
2. Make sure to install "open-vm-tools" and verify that the "vmtoolsd" service is set to autostart:
sudo apt-get install open-vm-tools
sudo systemctl enable vmtoolsd && sudo systemctl start vmtoolsd

3. Enable support for customization scripts:
sudo vmware-toolbox-cmd config set deployPkg enable-custom-scripts true

To check the current status of the parameter, execute:
sudo vmware-toolbox-cmd config get deployPkg enable-custom-scripts

4. Next, configure "VM Customization Specifications" on vCenter Server. During configuration, specify: OS type - Linux, hostname generation rules, time zone, TCP/IP settings, and add the following script:

#!/bin/bash

# Function to convert subnet mask to CIDR prefix
mask2cidr() {
    local mask=$1
    local n=0
    IFS=.

    for byte in $mask; do
        case $byte in
            255) n=$((n+8));;
            254) n=$((n+7));;
            252) n=$((n+6));;
            248) n=$((n+5));;
            240) n=$((n+4));;
            224) n=$((n+3));;
            192) n=$((n+2));;
            128) n=$((n+1));;
            0);;
            *) echo 24; return 1;;
        esac
    done

    echo $n
}

# Function to determine network management method with priority: NM -> SystemD -> Ifupdown
get_network_manager() {
    local interface=$1

    # 1. Check NetworkManager first
    if command -v nmcli >/dev/null 2>&1; then
        # Check if the interface is managed by NetworkManager
        if nmcli -t -f DEVICE device 2>/dev/null | grep -q "^${interface}$"; then
            echo "NetworkManager"
            return
        fi

        # Check if NetworkManager is active as a service
        if systemctl is-active NetworkManager >/dev/null 2>&1; then
            echo "NetworkManager"
            return
        fi

        # Check if there is a NetworkManager connection for this interface
        if nmcli -t -f NAME,DEVICE connection show 2>/dev/null | grep -q ":${interface}$"; then
            echo "NetworkManager"
            return
        fi
    fi

    # 2. Check systemd-networkd
    if systemctl is-active systemd-networkd >/dev/null 2>&1 && \
       systemctl is-active systemd-resolved >/dev/null 2>&1; then
        echo "SystemD"
        return
    fi

    # 3. Check ifupdown (traditional Debian method)
    if [ -f "/etc/network/interfaces" ]; then
        # Check if the interface is mentioned in the configuration
        if grep -q -E "^(auto|allow-hotplug|iface|mapping).*${interface}" /etc/network/interfaces; then
            echo "Ifupdown"
            return
        fi

        # Check for configs in interfaces.d
        if [ -d "/etc/network/interfaces.d" ]; then
            for config in /etc/network/interfaces.d/*; do
                if [ -f "$config" ] && grep -q "${interface}" "$config"; then
                    echo "Ifupdown"
                    return
                fi
            done
        fi
    fi

    # Check if the networking service (ifupdown) is active
    if systemctl is-active networking >/dev/null 2>&1; then
        echo "Ifupdown"
        return
    fi

    # 4. If nothing is found, check by service presence
    if systemctl is-enabled NetworkManager >/dev/null 2>&1; then
        echo "NetworkManager"
    elif systemctl is-enabled systemd-networkd >/dev/null 2>&1; then
        echo "SystemD"
    elif systemctl is-enabled networking >/dev/null 2>&1; then
        echo "Ifupdown"
    else
        # If nothing is determined, use ifupdown as a fallback
        echo "Ifupdown"
    fi
}

# Function to configure NetworkManager
configure_networkmanager() {
    local interface=$1
    local bootproto=$2
    local ipaddr=$3
    local netmask=$4
    local gateway=$5
    local dns_servers=$6
    local domain=$7

    # Delete existing connection for this interface
    nmcli connection delete "$interface" 2>/dev/null || true
    nmcli connection delete "Wired connection 1" 2>/dev/null || true
    nmcli connection delete "System ${interface}" 2>/dev/null || true

    # Create a new connection
    if [ "$bootproto" = "static" ]; then
        local prefix_length=$(mask2cidr "$netmask")
        nmcli con add type ethernet con-name "$interface" ifname "$interface" ipv4.method manual \
            ipv4.addresses "${ipaddr}/${prefix_length}" \
            ipv4.gateway "$gateway" \
            ipv4.dns "$dns_servers" \
            ipv4.dns-search "$domain" \
            autoconnect yes
    else
        nmcli con add type ethernet con-name "$interface" ifname "$interface" \
            ipv4.method auto autoconnect yes
    fi

    # Activate the connection
    nmcli con up "$interface"
}

# Function to configure SystemD networkd
configure_systemd() {
    local interface=$1
    local bootproto=$2
    local ipaddr=$3
    local netmask=$4
    local gateway=$5
    local dns_servers=$6
    local domain=$7
    local dns_from_dhcp=$8

    # Make sure the service is active
    systemctl enable systemd-networkd 2>/dev/null || true
    systemctl start systemd-networkd 2>/dev/null || true

    # Clear the /etc/systemd/network directory
    rm -rf /etc/systemd/network/*

    # Create basic configuration for loopback interface
    mkdir -p /etc/systemd/network
    cat > /etc/systemd/network/00-loopback.network <<EOF
[Match]
Name=lo

[Network]
Address=127.0.0.1/8
Address=::1/128
EOF

    # Create configuration for the main interface
    CONFIG_FILE="/etc/systemd/network/10-${interface}.network"

    if [ "$bootproto" = "static" ]; then
        if [ -z "$ipaddr" ] || [ -z "$netmask" ]; then
            echo "Error: IPADDR and NETMASK are required for static configuration"
            exit 1
        fi

        prefix_length=$(mask2cidr "$netmask")
        if [ -z "$prefix_length" ]; then
            prefix_length=24
        fi

        # Create config for static IP
        cat > "$CONFIG_FILE" <<EOF
[Match]
Name=$interface

[Network]
Address=$ipaddr/$prefix_length
EOF

        if [ -n "$gateway" ]; then
            echo "Gateway=$gateway" >> "$CONFIG_FILE"
        fi

        # Add DNS servers
        if [ -n "$dns_servers" ]; then
            for dns in $dns_servers; do
                echo "DNS=$dns" >> "$CONFIG_FILE"
            done
        fi
    else
        # Create config for DHCP
        cat > "$CONFIG_FILE" <<EOF
[Match]
Name=$interface

[Network]
DHCP=ipv4

[DHCPv4]
UseDomains=true
EOF

        # Configure DNS usage
        if [ "$dns_from_dhcp" = "yes" ]; then
            echo "UseDNS=yes" >> "$CONFIG_FILE"
        else
            echo "UseDNS=no" >> "$CONFIG_FILE"
            if [ -n "$dns_servers" ]; then
                for dns in $dns_servers; do
                    echo "DNS=$dns" >> "$CONFIG_FILE"
                done
            fi
        fi
    fi

    # Configure systemd-resolved if needed
    if [ -n "$dns_servers" ] || [ -n "$domain" ]; then
        mkdir -p /etc/systemd/resolved.conf.d
        cat > /etc/systemd/resolved.conf.d/10-${interface}.conf <<EOF
[Resolve]
EOF

        if [ -n "$dns_servers" ]; then
            echo "DNS=$dns_servers" >> /etc/systemd/resolved.conf.d/10-${interface}.conf
        fi

        if [ -n "$domain" ]; then
            echo "Domains=$domain" >> /etc/systemd/resolved.conf.d/10-${interface}.conf
        fi

        systemctl enable systemd-resolved 2>/dev/null || true
        systemctl start systemd-resolved 2>/dev/null || true

        # Create symlink for resolv.conf
        ln -sf /run/systemd/resolve/stub-resolv.conf /etc/resolv.conf 2>/dev/null || true
    fi

    systemctl restart systemd-networkd

    if systemctl is-active systemd-resolved >/dev/null 2>&1; then
        systemctl restart systemd-resolved
    fi
}

# Function to configure Ifupdown (/etc/network/interfaces)
configure_ifupdown() {
    local interface=$1
    local bootproto=$2
    local ipaddr=$3
    local netmask=$4
    local gateway=$5
    local dns_servers=$6
    local domain=$7

    echo "Configuring interface $interface using ifupdown" >&2

    # Create base interfaces file if it doesn't exist
    if [ ! -f /etc/network/interfaces ]; then
        mkdir -p /etc/network
        cat > /etc/network/interfaces <<EOF
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback
EOF
    fi

    # Remove ALL configuration for this interface
    # Create temporary file without current interface configuration
    tmpfile=$(mktemp)
    in_block=0

    while IFS= read -r line; do
        # Check if a new interface block starts
        if [[ "$line" =~ ^(auto|allow-hotplug|iface)[[:space:]]+$interface([[:space:]]|$) ]]; then
            in_block=1
            continue
        fi

        # If we are inside a block and encounter another block start, exit the block
        if [[ $in_block -eq 1 && "$line" =~ ^(auto|allow-hotplug|iface)[[:space:]]+ ]]; then
            in_block=0
        fi

        # If we are not inside the block of the interface being removed, save the line
        if [[ $in_block -eq 0 ]]; then
            echo "$line" >> "$tmpfile"
        fi
    done < /etc/network/interfaces

    # Copy back and remove temporary file
    mv "$tmpfile" /etc/network/interfaces
    chmod 644 /etc/network/interfaces

    # Remove possible duplicate empty lines
    sed -i '/^$/N; /^\n$/D' /etc/network/interfaces
    sed -i -e :a -e '/^\n*$/{$d;N;ba' -e '}' /etc/network/interfaces

    # Add new configuration
    {
        echo ""
        echo "auto $interface"
        if [ "$bootproto" = "static" ]; then
            echo "iface $interface inet static"
            echo "    address $ipaddr"
            echo "    netmask $netmask"
            [ -n "$gateway" ] && echo "    gateway $gateway"
            [ -n "$dns_servers" ] && echo "    dns-nameservers $dns_servers"
            [ -n "$domain" ] && echo "    dns-search $domain"
        else
            echo "iface $interface inet dhcp"
        fi
    } >> /etc/network/interfaces

    # Configure DNS via resolvconf if installed
    if command -v resolvconf >/dev/null 2>&1; then
        # Create temporary file for resolvconf
        TMP_RESOLV="/tmp/resolv.conf.${interface}"
        echo "# Generated by network configuration script" > "$TMP_RESOLV"

        if [ -n "$domain" ]; then
            echo "domain $domain" >> "$TMP_RESOLV"
            echo "search $domain" >> "$TMP_RESOLV"
        fi

        if [ -n "$dns_servers" ]; then
            for dns in $dns_servers; do
                echo "nameserver $dns" >> "$TMP_RESOLV"
            done
        fi

        # Update resolvconf
        resolvconf -a "${interface}" < "$TMP_RESOLV" 2>/dev/null || true
        rm -f "$TMP_RESOLV"
    else
        # Direct configuration of /etc/resolv.conf
        if [ -n "$dns_servers" ] || [ -n "$domain" ]; then
            echo "# Generated by network configuration script" > /etc/resolv.conf

            if [ -n "$domain" ]; then
                echo "domain $domain" >> /etc/resolv.conf
                echo "search $domain" >> /etc/resolv.conf
            fi

            if [ -n "$dns_servers" ]; then
                for dns in $dns_servers; do
                    echo "nameserver $dns" >> /etc/resolv.conf
                done
            fi
        fi
    fi

    # Restart network service
    if systemctl is-active networking >/dev/null 2>&1; then
        systemctl restart networking
    else
        # Old method of network restart
        ifdown "$interface" 2>/dev/null || true
        ifup "$interface" 2>/dev/null || true
    fi
}

# --- Function to clean logs and temporary files ---
clean_system() {
    # Clean logs (preserving directory structure)
    find /var/log -type f -name "*.log" -exec truncate -s 0 {} \; 2>/dev/null || true
    find /var/log -type f -name "*.gz" -delete 2>/dev/null || true
    find /var/log -type f -name "*.old" -delete 2>/dev/null || true
    find /var/log -type f -name "lastlog" -exec rm -f {} \; 2>/dev/null || true

    # Clean temporary files
    rm -rf /tmp/* 2>/dev/null || true
    rm -rf /var/tmp/* 2>/dev/null || true

    # Clean command history and user data
    for user_home in /home/*; do
        if [[ -d "$user_home" ]]; then
            user=$(basename "$user_home")
            # Clean bash_history and other histories
            truncate -s 0 "$user_home/.bash_history" 2>/dev/null || true
            # Clean application caches
            rm -rf "$user_home/.cache/*" 2>/dev/null || true
        fi
    done

    # Clean root
    truncate -s 0 /root/.bash_history 2>/dev/null || true
    rm -rf /root/.cache/* 2>/dev/null || true

    # Delete random seed files
    rm -f /var/lib/systemd/random-seed 2>/dev/null || true
}

# --- Function to delete SSH host keys ---
reset_ssh_keys() {
    rm -f /etc/ssh/ssh_host_* 2>/dev/null || true

    # Regenerate SSH server keys
    if command -v dpkg-reconfigure >/dev/null 2>&1; then
        dpkg-reconfigure -f noninteractive openssh-server 2>/dev/null || true
    fi

    # Alternative method for Debian
    if [ -x /usr/sbin/sshd ]; then
        /usr/sbin/sshd-keygen -A 2>/dev/null || true
    fi
}

# ============================================================
# Main script logic
# ============================================================
if [ "$1" = "precustomization" ]; then
    # Perform system cleanup
    clean_system

    # Check and create /etc/network/interfaces
    if [ ! -f /etc/network/interfaces ]; then
        echo "Creating /etc/network/interfaces file"
        mkdir -p /etc/network
        cat > /etc/network/interfaces <<EOF
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback
EOF
    fi

    # Check and create /etc/sysconfig/network-scripts directory if needed
    if [ ! -d "/etc/sysconfig/network-scripts" ]; then
        mkdir -p /etc/sysconfig/network-scripts 2>/dev/null || true
    fi

    # Pre-configuration stage
    VMCUST_DIR=$(ls -d /var/run/.vmware-imgcust* 2>/dev/null | head -n 1)
    if [ -n "$VMCUST_DIR" ]; then
        CUST_CFG_PATH="$VMCUST_DIR/cust.cfg"
        if [ -f "$CUST_CFG_PATH" ]; then
            cp "$CUST_CFG_PATH" "/root/cust.cfg"
        fi
    fi

elif [ "$1" = "postcustomization" ]; then
    # Post-configuration stage
    reset_ssh_keys

    if [ ! -f "/root/cust.cfg" ]; then
        echo "Error: configuration file /root/cust.cfg not found"
        exit 1
    fi

    CFG_FILE="/root/cust.cfg"

    # Parse configuration parameters
    BOOTPROTO=$(awk -F' = ' '/^BOOTPROTO/ {line=$2} END{print tolower(line)}' "$CFG_FILE")
    IPADDR=$(awk -F' = ' '/^IPADDR/ {line=$2} END{print line}' "$CFG_FILE")
    NETMASK=$(awk -F' = ' '/^NETMASK/ {line=$2} END{print line}' "$CFG_FILE")
    GATEWAY=$(awk -F' = ' '/^GATEWAY/ {line=$2} END{print line}' "$CFG_FILE")
    HOSTNAME=$(awk -F' = ' '/^HOSTNAME/ {line=$2} END{print line}' "$CFG_FILE")
    DOMAIN=$(awk -F' = ' '/^DOMAINNAME/ {line=$2} END{print line}' "$CFG_FILE")
    MACADDR=$(awk -F' = ' '/^MACADDR/ {line=$2} END{print tolower(line)}' "$CFG_FILE")
    DNS_SERVERS=$(awk -F' = ' '/^NAMESERVER\|[0-9]/ {print $2}' "$CFG_FILE" | tr '\n' ' ' | sed 's/ $//')
    DNS_FROM_DHCP=$(awk -F' = ' '/^DNSFROMDHCP/ {line=$2} END{print tolower(line)}' "$CFG_FILE")
    TIMEZONE=$(awk -F' = ' '/^TIMEZONE/ {line=$2} END{print line}' "$CFG_FILE")
    UTC=$(awk -F' = ' '/^UTC/ {line=$2} END{print tolower(line)}' "$CFG_FILE")

    # Determine network interface
    INTERFACE=$(ip -o link | awk -v mac="$MACADDR" 'tolower($0) ~ mac {gsub(":", "", $2); print $2}')

    if [ -z "$INTERFACE" ]; then
        INTERFACE=$(ip route | awk '/default/ {print $5; exit}')
    fi

    if [ -z "$INTERFACE" ]; then
        # Last attempt: take the first Ethernet interface
        INTERFACE=$(ip -o link | awk -F': ' '$2 !~ /^lo|virbr|docker|veth/ {print $2; exit}' | sed 's/@.*//')
    fi

    if [ -z "$INTERFACE" ]; then
        echo "Error: could not determine network interface"
        exit 1
    fi

    # Determine network management method
    NET_MGR=$(get_network_manager "$INTERFACE")
    echo "Determined network management method: $NET_MGR for interface $INTERFACE"

    case "$NET_MGR" in
        "NetworkManager")
            configure_networkmanager "$INTERFACE" "$BOOTPROTO" "$IPADDR" "$NETMASK" \
                "$GATEWAY" "$DNS_SERVERS" "$DOMAIN"
            ;;
        "SystemD")
            configure_systemd "$INTERFACE" "$BOOTPROTO" "$IPADDR" "$NETMASK" \
                "$GATEWAY" "$DNS_SERVERS" "$DOMAIN" "$DNS_FROM_DHCP"
            ;;
        "Ifupdown")
            configure_ifupdown "$INTERFACE" "$BOOTPROTO" "$IPADDR" "$NETMASK" \
                "$GATEWAY" "$DNS_SERVERS" "$DOMAIN"
            ;;
        *)
            echo "Unknown network management method, using ifupdown as fallback"
            configure_ifupdown "$INTERFACE" "$BOOTPROTO" "$IPADDR" "$NETMASK" \
                "$GATEWAY" "$DNS_SERVERS" "$DOMAIN"
            ;;
    esac

    # Common settings
    hostnamectl set-hostname "$HOSTNAME" 2>/dev/null || echo "$HOSTNAME" > /etc/hostname
    sed -i "/127\.0\.1\.1/d" /etc/hosts
    echo "127.0.1.1 $HOSTNAME.$DOMAIN $HOSTNAME" >> /etc/hosts

    # Configure time zone
    if [ -n "$TIMEZONE" ]; then
        timedatectl set-timezone "$TIMEZONE" 2>/dev/null || true

        # Alternative method for Debian
        if [ -f "/usr/share/zoneinfo/$TIMEZONE" ]; then
            cp "/usr/share/zoneinfo/$TIMEZONE" /etc/localtime 2>/dev/null || true
            echo "$TIMEZONE" > /etc/timezone 2>/dev/null || true
        fi
    fi

    # Configure BIOS time format (UTC or local)
    if [ -n "$UTC" ]; then
        if [ "$UTC" = "yes" ]; then
            # Set UTC time in BIOS
            timedatectl set-local-rtc 0 2>/dev/null || true
        else
            # Set local time in BIOS
            timedatectl set-local-rtc 1 2>/dev/null || true
        fi
    fi

    # Save configuration
    CONFIG_LOG="/root/vm-customization.log"
    {
        echo "=========================================="
        echo "Configuration completed: $(date)"
        echo "=========================================="
        echo "CONFIG_SOURCE=$CFG_FILE"
        echo "BOOTPROTO=$BOOTPROTO"
        echo "INTERFACE=$INTERFACE"
        echo "NETWORK_MANAGER=$NET_MGR"
        echo "HOSTNAME=$HOSTNAME"
        echo "DOMAIN=$DOMAIN"
        echo "TIMEZONE=$TIMEZONE"
        echo "UTC=$UTC"

        [ -n "$DNS_FROM_DHCP" ] && echo "DNS_FROM_DHCP=$DNS_FROM_DHCP"
        [ -n "$DNS_SERVERS" ] && echo "DNS_SERVERS=\"$DNS_SERVERS\""

        if [ "$BOOTPROTO" = "static" ]; then
            echo "IP_ADDRESS=$IPADDR"
            echo "NETMASK=$NETMASK"
            [ -n "$GATEWAY" ] && echo "GATEWAY=$GATEWAY"
        fi
    } > "$CONFIG_LOG"

    rm -f "/root/cust.cfg"

    # Sync changes to disk
    sync

    echo "Configuration completed successfully. Network management method: $NET_MGR"

    ##############################################################################################
    # PLACE FOR ADDITIONAL SYSTEM CONFIGURATION
    # Here you can add commands for final machine setup:
    # - Installing additional necessary software
    # - Configuration via Ansible or other configuration management systems
    # - Execution of user scripts
    # - Setting up monitoring, logging, and other services

    # Example: install basic packages
    # apt-get update && apt-get install -y curl wget net-tools

    ##############################################################################################
fi

This script covers all possible network configuration options: IfUpDown, NetworkManager, Systemd-Networkd, both with static IP and DHCP.