VMware Firstboot Network Configuration Script For Ubuntu

April 12, 2025 AB Comments 0 Comment

🧭 Goal

This script configures static network settings (hostname, IP address, subnet, gateway, DNS) automatically on the first boot of a VMware virtual machine. It pulls values passed via VMware’s guestinfo properties and applies them using Netplan.

🛠️ Prerequisites

Requirement	Description
OS	Ubuntu 18.04+ (using Netplan)
VMware Tools	`open-vm-tools` or equivalent must be installed
VMware GuestInfo Settings	Must set `guestinfo.labvm.*` via vSphere or cloud-init

📦 Input Parameters via `guestinfo`

Set the following advanced options in vSphere or through OVF:

Key	Example Value	Description
`guestinfo.labvm.hostname`	`labvm01`	Hostname for the VM
`guestinfo.labvm.ipaddr`	`192.168.1.101`	Static IP address
`guestinfo.labvm.subnet`	`24`	Subnet mask in CIDR
`guestinfo.labvm.gateway`	`192.168.1.1`	Default gateway
`guestinfo.labvm.dns`	`8.8.8.8,1.1.1.1`	DNS servers (comma-separated)

🧠 How the Script Works

Fetches guestinfo values using vmtoolsd --cmd info-get ...
Validates all inputs (non-empty, valid CIDR for subnet)
Detects default interface automatically
Sets the hostname using hostnamectl
Generates a Netplan YAML config in /etc/netplan/01-netcfg.yaml
Applies Netplan, validates it, sets file permissions
Logs each step to /var/log/vmware-netconfig.log
If everything succeeds:
- touch /etc/firstboot-done
- systemctl disable firstboot-network-config.service

⚙️ Script Path & Permissions

Create a script as:

#!/bin/bash

LOG_FILE="/var/log/vmware-netconfig.log"

# Logging function
log() {
  local level="$1"
  local msg="$2"
  echo "$(date '+%F %T') [$level] $msg" | tee -a "$LOG_FILE"
}

log "INFO" "Starting network configuration"

# Wait for VMware Tools (vmtoolsd)
for i in {1..10}; do
  if command -v vmtoolsd >/dev/null && vmtoolsd --cmd "info-get guestinfo.ping" &>/dev/null; then
    log "INFO" "VMware Tools (vmtoolsd) is available"
    break
  fi
  log "INFO" "Waiting for vmtoolsd to become available..."
  sleep 1
done

# Fetch values using vmtoolsd
HOSTNAME=$(vmtoolsd --cmd "info-get guestinfo.labvm.hostname")
IPADDR=$(vmtoolsd --cmd "info-get guestinfo.labvm.ipaddr")
SUBNET=$(vmtoolsd --cmd "info-get guestinfo.labvm.subnet")
GATEWAY=$(vmtoolsd --cmd "info-get guestinfo.labvm.gateway")
DNS=$(vmtoolsd --cmd "info-get guestinfo.labvm.dns")

# Log values
log "INFO" "HOSTNAME = $HOSTNAME"
log "INFO" "IPADDR   = $IPADDR"
log "INFO" "SUBNET   = $SUBNET"
log "INFO" "GATEWAY  = $GATEWAY"
log "INFO" "DNS      = $DNS"

# Validate inputs
if [[ -z "$HOSTNAME" || -z "$IPADDR" || -z "$SUBNET" || -z "$GATEWAY" || -z "$DNS" ]]; then
  log "ERROR" "Missing one or more network parameters. Aborting."
  exit 1
fi

# Validate subnet
if ! [[ "$SUBNET" =~ ^[0-9]+$ ]] || [ "$SUBNET" -lt 0 ] || [ "$SUBNET" -gt 32 ]; then
  log "ERROR" "Invalid subnet: $SUBNET. Must be CIDR (e.g., 24)."
  exit 1
fi

# Detect default interface
for i in {1..10}; do
  INTERFACE=$(ip route | awk '/default/ {print $5; exit}')
  if [ -n "$INTERFACE" ]; then
    break
  fi
  sleep 1
done

if [ -z "$INTERFACE" ]; then
  INTERFACE=$(ip -o link show | awk -F': ' '!/lo/ {print $2; exit}')
  log "WARNING" "Default route not found. Fallback to: $INTERFACE"
fi

log "INFO" "Using interface: $INTERFACE"

# Set hostname
log "INFO" "Setting hostname to $HOSTNAME"
if hostnamectl set-hostname "$HOSTNAME"; then
  grep -q "$HOSTNAME" /etc/hosts || echo "127.0.1.1 $HOSTNAME" >> /etc/hosts
else
  log "ERROR" "Failed to set hostname"
  exit 1
fi

# Write Netplan configuration
NETPLAN_FILE="/etc/netplan/01-netcfg.yaml"
log "INFO" "Writing Netplan config to $NETPLAN_FILE"

cat <<EOF > "$NETPLAN_FILE"
network:
  version: 2
  renderer: networkd
  ethernets:
    $INTERFACE:
      dhcp4: no
      addresses:
        - ${IPADDR}/${SUBNET}
      nameservers:
        addresses: [${DNS//,/\, }]
      routes:
        - to: default
          via: $GATEWAY
EOF

chmod 600 "$NETPLAN_FILE"
log "INFO" "Netplan config file permissions set to 600"

# Apply Netplan and check result
log "INFO" "Applying Netplan"
if netplan apply; then
  log "INFO" "Netplan applied successfully"
else
  log "ERROR" "Netplan apply failed"
  exit 1
fi

# Only if all succeeded:
touch /etc/firstboot-done
systemctl disable firstboot-network-config.service
log "INFO" "Network configuration completed successfully and service disabled"

100

101

102

103

104

105

106

107

108

109

110

#!/bin/bash

LOG_FILE="/var/log/vmware-netconfig.log"

# Logging function

log() {

local level="$1"

local msg="$2"

echo "$(date '+%F %T') [$level] $msg" | tee -a "$LOG_FILE"

}

log "INFO" "Starting network configuration"

# Wait for VMware Tools (vmtoolsd)

for i in {1..10}; do

if command -v vmtoolsd >/dev/null && vmtoolsd --cmd "info-get guestinfo.ping" &>/dev/null; then

log "INFO" "VMware Tools (vmtoolsd) is available"

break

log "INFO" "Waiting for vmtoolsd to become available..."

sleep 1

done

# Fetch values using vmtoolsd

HOSTNAME=$(vmtoolsd --cmd "info-get guestinfo.labvm.hostname")

IPADDR=$(vmtoolsd --cmd "info-get guestinfo.labvm.ipaddr")

SUBNET=$(vmtoolsd --cmd "info-get guestinfo.labvm.subnet")

GATEWAY=$(vmtoolsd --cmd "info-get guestinfo.labvm.gateway")

DNS=$(vmtoolsd --cmd "info-get guestinfo.labvm.dns")

# Log values

log "INFO" "HOSTNAME = $HOSTNAME"

log "INFO" "IPADDR = $IPADDR"

log "INFO" "SUBNET = $SUBNET"

log "INFO" "GATEWAY = $GATEWAY"

log "INFO" "DNS = $DNS"

# Validate inputs

if [[ -z "$HOSTNAME" || -z "$IPADDR" || -z "$SUBNET" || -z "$GATEWAY" || -z "$DNS" ]]; then

log "ERROR" "Missing one or more network parameters. Aborting."

exit 1

# Validate subnet

if ! [[ "$SUBNET" =~ ^[0-9]+$ ]] || [ "$SUBNET" -lt 0 ] || [ "$SUBNET" -gt 32 ]; then

log "ERROR" "Invalid subnet: $SUBNET. Must be CIDR (e.g., 24)."

exit 1

# Detect default interface

for i in {1..10}; do

INTERFACE=$(ip route | awk '/default/ {print $5; exit}')

if [ -n "$INTERFACE" ]; then

break

sleep 1

done

if [ -z "$INTERFACE" ]; then

INTERFACE=$(ip -o link show | awk -F': ' '!/lo/ {print $2; exit}')

log "WARNING" "Default route not found. Fallback to: $INTERFACE"

log "INFO" "Using interface: $INTERFACE"

# Set hostname

log "INFO" "Setting hostname to $HOSTNAME"

if hostnamectl set-hostname "$HOSTNAME"; then

grep -q "$HOSTNAME" /etc/hosts || echo "127.0.1.1 $HOSTNAME" >> /etc/hosts

else

log "ERROR" "Failed to set hostname"

exit 1

# Write Netplan configuration

NETPLAN_FILE="/etc/netplan/01-netcfg.yaml"

log "INFO" "Writing Netplan config to $NETPLAN_FILE"

cat <<EOF > "$NETPLAN_FILE"

network:

version: 2

renderer: networkd

ethernets:

$INTERFACE:

dhcp4: no

addresses:

- ${IPADDR}/${SUBNET}

nameservers:

addresses: [${DNS//,/\, }]

routes:

- to: default

via: $GATEWAY

EOF

chmod 600 "$NETPLAN_FILE"

log "INFO" "Netplan config file permissions set to 600"

# Apply Netplan and check result

log "INFO" "Applying Netplan"

if netplan apply; then

log "INFO" "Netplan applied successfully"

else

log "ERROR" "Netplan apply failed"

exit 1

# Only if all succeeded:

touch /etc/firstboot-done

systemctl disable firstboot-network-config.service

log "INFO" "Network configuration completed successfully and service disabled"

Save the script as:

Set permission to the file

chmod +x /usr/local/bin/configure_network.sh

1	chmod +x /usr/local/bin/configure_network.sh

🛑 Systemd Service Setup (to run on first boot)

Create file: /etc/systemd/system/firstboot-network-config.service

[Unit]
Description=First Boot Network Configuration
After=network.target
ConditionPathExists=!/etc/firstboot-done

[Service]
ExecStart=/usr/local/bin/configure_network.sh
Type=oneshot
RemainAfterExit=true

[Install]
WantedBy=multi-user.target

[Unit]

Description=First Boot Network Configuration

After=network.target

ConditionPathExists=!/etc/firstboot-done

[Service]

ExecStart=/usr/local/bin/configure_network.sh

Type=oneshot

RemainAfterExit=true

[Install]

WantedBy=multi-user.target

Enable the service

systemctl daemon-reexec
systemctl daemon-reload
systemctl enable firstboot-network-config.service

systemctl daemon-reexec

systemctl daemon-reload

systemctl enable firstboot-network-config.service

It will run once during boot, then disable itself.

📄 Log Output Example

All activity is logged to /var/log/vmware-netconfig.log:

2025-04-12 14:30:01 [INFO] Starting network configuration
2025-04-12 14:30:02 [INFO] HOSTNAME = labvm01
2025-04-12 14:30:02 [INFO] IPADDR   = 192.168.1.101
2025-04-12 14:30:02 [INFO] SUBNET   = 24
2025-04-12 14:30:02 [INFO] GATEWAY  = 192.168.1.1
2025-04-12 14:30:02 [INFO] DNS      = 8.8.8.8
2025-04-12 14:30:02 [INFO] Using interface: ens33
2025-04-12 14:30:02 [INFO] Writing Netplan config to /etc/netplan/01-netcfg.yaml
2025-04-12 14:30:02 [INFO] Netplan config file permissions set to 600
2025-04-12 14:30:02 [INFO] Applying Netplan
2025-04-12 14:30:03 [INFO] Netplan applied successfully
2025-04-12 14:30:03 [INFO] Network configuration completed successfully and service disabled

2025-04-12 14:30:01 [INFO] Starting network configuration

2025-04-12 14:30:02 [INFO] HOSTNAME = labvm01

2025-04-12 14:30:02 [INFO] IPADDR = 192.168.1.101

2025-04-12 14:30:02 [INFO] SUBNET = 24

2025-04-12 14:30:02 [INFO] GATEWAY = 192.168.1.1

2025-04-12 14:30:02 [INFO] DNS = 8.8.8.8

2025-04-12 14:30:02 [INFO] Using interface: ens33

2025-04-12 14:30:02 [INFO] Writing Netplan config to /etc/netplan/01-netcfg.yaml

2025-04-12 14:30:02 [INFO] Netplan config file permissions set to 600

2025-04-12 14:30:02 [INFO] Applying Netplan

2025-04-12 14:30:03 [INFO] Netplan applied successfully

2025-04-12 14:30:03 [INFO] Network configuration completed successfully and service disabled

🧪 Troubleshooting

Issue	Solution
🔴 `Could not detect default interface`	Ensure network is up and `ip route` returns default
⚠️ `gateway4 is deprecated`	Already fixed — script uses `routes:`
🔐 `Permissions for 01-netcfg.yaml are too open`	Script sets `chmod 600`
🛑 `Netplan apply fails`	Check `/etc/netplan/01-netcfg.yaml` syntax and try `netplan try` manually

You can create an OVF template with this script pre-injected, enabling fully automated VM deployments where network settings and other configurations are applied seamlessly during the initial boot. Note, that during the deployment, the following values need to be updated in VM Advance settings.

You can use the following script to deploy the VM and update the respective values.

#Connect-VIServer
$VMHost = Get-VMHost
$DataStore = Get-Datastore -Name "Datastore-SSD-01"
$OVF = "D:\Lab\Installer\OVF\Ubuntu-Clean-Build\Ubuntu-Clean-Build.ovf"

# Define an array of PSObjects
$vmList = @()

# Add entries to the array
$vmList += [pscustomobject]@{
    Hostname = "labvm01"
    IP       = "192.168.1.101"
    Subnet   = "24"
    Gateway  = "192.168.1.1"
    DNS      = "8.8.8.8"
}

foreach($vmObj in $vmList){
    Import-VApp -Name $vmObj.Hostname -Datastore $DataStore -VMHost $VMHost -DiskStorageFormat Thin -Source $OVF -Force
    $VM = Get-VM $vmObj.Hostname    
    $VM | New-AdvancedSetting -Name "guestinfo.labvm.hostname" -Value $vmObj.Hostname -Confirm:$false
    $VM | New-AdvancedSetting -Name "guestinfo.labvm.ipaddr" -Value $vmObj.IP -Confirm:$false
    $VM | New-AdvancedSetting -Name "guestinfo.labvm.gateway" -Value $vmObj.Gateway -Confirm:$false
    $VM | New-AdvancedSetting -Name "guestinfo.labvm.subnet" -Value $vmObj.Subnet -Confirm:$false
    $VM | New-AdvancedSetting -Name "guestinfo.labvm.dns" -Value $vmObj.DNS -Confirm:$false
    $VM | start-vm
}

#Connect-VIServer

$VMHost = Get-VMHost

$DataStore = Get-Datastore -Name "Datastore-SSD-01"

$OVF = "D:\Lab\Installer\OVF\Ubuntu-Clean-Build\Ubuntu-Clean-Build.ovf"

# Define an array of PSObjects

$vmList = @()

# Add entries to the array

$vmList += [pscustomobject]@{

Hostname = "labvm01"

IP = "192.168.1.101"

Subnet = "24"

Gateway = "192.168.1.1"

DNS = "8.8.8.8"

}

foreach($vmObj in $vmList){

Import-VApp -Name $vmObj.Hostname -Datastore $DataStore -VMHost $VMHost -DiskStorageFormat Thin -Source $OVF -Force

$VM = Get-VM $vmObj.Hostname

$VM | New-AdvancedSetting -Name "guestinfo.labvm.hostname" -Value $vmObj.Hostname -Confirm:$false

$VM | New-AdvancedSetting -Name "guestinfo.labvm.ipaddr" -Value $vmObj.IP -Confirm:$false

$VM | New-AdvancedSetting -Name "guestinfo.labvm.gateway" -Value $vmObj.Gateway -Confirm:$false

$VM | New-AdvancedSetting -Name "guestinfo.labvm.subnet" -Value $vmObj.Subnet -Confirm:$false

$VM | New-AdvancedSetting -Name "guestinfo.labvm.dns" -Value $vmObj.DNS -Confirm:$false

$VM | start-vm

}

Virtualization

VMware Firstboot Network Configuration Script For Ubuntu

April 12, 2025 AB Comments 0 Comment

🧭 Goal

🛠️ Prerequisites

📦 Input Parameters via `guestinfo`

🧠 How the Script Works

⚙️ Script Path & Permissions

🛑 Systemd Service Setup (to run on first boot)

📄 Log Output Example

🧪 Troubleshooting

Leave a Reply Cancel reply

🧭 Goal

🛠️ Prerequisites

📦 Input Parameters via guestinfo

🧠 How the Script Works

⚙️ Script Path & Permissions

🛑 Systemd Service Setup (to run on first boot)

📄 Log Output Example

🧪 Troubleshooting

Leave a Reply Cancel reply

📦 Input Parameters via `guestinfo`