install_rhel.sh

#!/usr/bin/env bash
set -euo pipefail

echo "== RHEL / VirtualBox Guest Additions setup =="
echo "Kernel: $(uname -r)"

echo
echo "== 1) Update packages (recommended to reduce kernel/module mismatch) =="
sudo dnf -y update || true

echo
echo "== 2) Install build dependencies for Guest Additions kernel modules =="
# Common requirements called out for RHEL/CentOS/Fedora-style guests:
# gcc, make, perl, kernel-devel, kernel-headers (+ often libelf tools)
sudo dnf -y install gcc make perl kernel-devel kernel-headers elfutils-libelf-devel || \
sudo dnf -y install gcc make perl kernel-devel kernel-headers

echo
echo "== 3) Confirm kernel-devel matches the running kernel =="
# Many Guest Additions failures are caused by mismatch between uname -r and installed kernel-devel.
rpm -q "kernel-devel-$(uname -r)" || {
  echo "WARNING: kernel-devel for the running kernel is NOT installed."
  echo "Attempting to install matching kernel-devel package..."
  sudo dnf -y install "kernel-devel-$(uname -r)" || true
}

echo
echo "== 4) Mount the VirtualBox Guest Additions ISO =="
# In VirtualBox UI: Devices -> Insert/Install Guest Additions
sudo mkdir -p /mnt/cdrom
# Try a couple common device names
if sudo mount /dev/cdrom /mnt/cdrom 2>/dev/null; then
  echo "Mounted /dev/cdrom to /mnt/cdrom"
elif sudo mount /dev/sr0 /mnt/cdrom 2>/dev/null; then
  echo "Mounted /dev/sr0 to /mnt/cdrom"
else
  echo "ERROR: Could not mount Guest Additions ISO."
  echo "Make sure you selected: Devices -> Insert/Install Guest Additions CD Image in VirtualBox."
  exit 1
fi

echo
echo "== 5) Run the Guest Additions installer =="
cd /mnt/cdrom
if [[ -x ./VBoxLinuxAdditions.run ]]; then
  sudo ./VBoxLinuxAdditions.run
else
  echo "ERROR: VBoxLinuxAdditions.run not found on the mounted ISO."
  echo "Check that the VBoxGuestAdditions ISO was inserted."
  exit 1
fi

echo
echo "== 6) Verify kernel modules loaded (after install) =="
# Common modules include vboxguest and vboxsf (and often vboxvideo)
(lsmod | grep -E 'vboxguest|vboxsf|vboxvideo' || true)

echo
echo "== 7) Reboot recommended =="
echo "Guest Additions often require a reboot to fully activate (display resize, shared folders, etc.)."
echo "Run: sudo reboot"
``