Simple Nagios check for NRPE / PeriodicNoise to check whether an Ubuntu server required reboot

check_reboot_required.py

#!/usr/bin/env python

import apt, os, re, sys, subprocess

if os.path.exists('/var/run/reboot-required'):
  print 'reboot-required marker file exists'
  sys.exit(1)

kernels = []

cache = apt.Cache(memonly=True)
for package in cache:
  if package.installed and re.match('^linux-image-[0-9].*', package.name):
    kernels.append(package.name)

kernels.sort()
latest = kernels[-1]

active_kernel = subprocess.check_output(['uname', '-r']).strip()

if 'linux-image-%s' % active_kernel == latest:
  print 'reboot-required marker not found, kernel matches'
  sys.exit(0)
else:
  print 'reboot-required marker not found, kernel version does not match: %s != %s' % (latest, active_kernel)
  sys.exit(1)