Small script to retrieve the OS version from GCP compute engine

Written by

Sorin Tudor

in

I add here a small script that was drafted with AI but was tested and modified by me so that it returns the OS version for all of the VM instances under a project in GCP

#!/bin/bash

# Prompt for the project ID
read -p "Enter your Google Cloud Project ID: " PROJECT_ID

if [ -z "$PROJECT_ID" ]; then
  echo "Project ID cannot be empty."
  exit 1
fi

echo "Fetching VM instances and their OS versions for project: $PROJECT_ID"
echo "--------------------------------------------------------------------"
echo "Instance Name        | Zone                 | OS (from inventory)"
echo "---------------------|----------------------|---------------------"

# Get all instances (name and zone) in the project
# The `instances list` command can list instances across all zones if no --zones flag is specified.
# However, `instances describe` requires a specific zone.
# So, we list name and zone, then describe each.
gcloud compute instances list --project="$PROJECT_ID" --format="value(name,zone)" | while read -r INSTANCE_NAME ZONE; do
  # Get the licenses of the boot disk for the current instance
  # We filter for the disk that has boot=true
  # If multiple licenses, it takes the first one. Often OS licenses are listed.
  OS_INFO=$(gcloud compute instances os-inventory describe "$INSTANCE_NAME" \
    --zone="$ZONE" \
    --project="$PROJECT_ID" \
    --format="value(SystemInformation.LongName)" 2>/dev/null)

  # If no license info found, display a placeholder
  if [ -z "$OS_INFO" ] || [ "$OS_INFO" = "None" ]; then
    OS_VERSION="N/A or Custom"
  else
    # The command above should already give the last part, but an extra check/cleanup
    OS_VERSION="$OS_INFO"
  fi

  # Print the instance name, zone, and OS version in a formatted way
  printf "%-20s | %-20s | %s\n" "$INSTANCE_NAME" "$ZONE" "$OS_VERSION"
done

echo "--------------------------------------------------------------------"

I don’t think any other details are needed in regard to this.

Cheers,

Sorin

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