Disk Resize Script

resize.sh

#!/bin/bash

# ==============================================================================
# resize_disk.sh (v6 - Based on Your Working Commands)
#
# Uses the exact command sequence that you verified works manually.
#
# ==============================================================================

set -e

GREEN='\033[0;32m'
YELLOW='\033[1;33m'
RED='\033[0;31m'
NC='\033[0m'

if [ "$EUID" -ne 0 ]; then
  echo -e "${RED}Please run this script as root or with sudo.${NC}"
  exit 1
fi

echo -e "${GREEN}--- Starting Disk Resize Script ---${NC}"

if ! command -v growpart &> /dev/null; then
    echo -e "${YELLOW}'growpart' command not found. Installing 'cloud-guest-utils'...${NC}"
    apt-get update
    apt-get install -y cloud-guest-utils
    echo -e "${GREEN}'cloud-guest-utils' installed successfully.${NC}"
fi

ROOT_FS=$(df --output=source / | tail -n 1)
echo "Detected root filesystem: ${ROOT_FS}"

if echo "${ROOT_FS}" | grep -q "mapper"; then
    IS_LVM=true
    echo "LVM setup detected."
else
    IS_LVM=false
    echo "Standard partition setup detected."
fi

if [ "$IS_LVM" = true ]; then
    VG_NAME=$(lvs --noheadings -o vg_name "${ROOT_FS}" | xargs)
    echo "Found Volume Group: ${VG_NAME}"

    PV_PATH=$(vgs --noheadings -o pv_name "${VG_NAME}" | xargs)
    echo "LVM is on Physical Volume: ${PV_PATH}"

    # Extract disk and partition number from PV_PATH (e.g., /dev/sda3)
    # Use basename to get just "sda3", then strip the number to get "sda"
    PV_DEVICE=$(basename "${PV_PATH}")
    PART_NUM=$(echo "${PV_DEVICE}" | grep -o '[0-9]*$')
    DISK_NAME=$(echo "${PV_DEVICE}" | sed 's/[0-9]*$//')
    DISK_PATH="/dev/${DISK_NAME}"
    
    echo "Disk: ${DISK_PATH}, Partition: ${PART_NUM}"
    
    echo "Step 1: Growing partition ${PART_NUM} on disk ${DISK_PATH}..."
    growpart "${DISK_PATH}" "${PART_NUM}"

    echo "Step 2: Resizing LVM Physical Volume on ${PV_PATH}..."
    pvresize "${PV_PATH}"

    echo "Step 3: Extending LVM Logical Volume ${ROOT_FS} to use all free space..."
    lvextend -l +100%FREE "${ROOT_FS}"

    echo "Step 4: Resizing the filesystem on ${ROOT_FS}..."
    resize2fs "${ROOT_FS}"
else
    PART_PATH="${ROOT_FS}"
    PART_DEVICE=$(basename "${PART_PATH}")
    PART_NUM=$(echo "${PART_DEVICE}" | grep -o '[0-9]*$')
    DISK_NAME=$(echo "${PART_DEVICE}" | sed 's/[0-9]*$//')
    DISK_PATH="/dev/${DISK_NAME}"

    echo "Step 1: Growing partition ${PART_NUM} on disk ${DISK_PATH}..."
    growpart "${DISK_PATH}" "${PART_NUM}"

    echo "Step 2: Resizing the filesystem on ${PART_PATH}..."
    resize2fs "${PART_PATH}"
fi

echo -e "\n${GREEN}--- Resize Complete! ---${NC}"
echo "Verifying the new size of the root filesystem:"
df -h /

exit 0