Python script to monitor stale/unmounted NFS mounts and automatically remount them

monitor_nfs.py

#!/bin/python

import signal
import os
import subprocess
from scandir import scandir


# Create a new Alarm Exception
class Alarm(Exception):
    pass


def alarm_handler(signum, frame):
    raise Alarm


# Timeout for signalling the alarm handler
TIMEOUT = 120

stream = os.popen("cat /etc/fstab | grep nfs |awk '{print $2}'")
nfsMounts = stream.read()
nfsMounts = nfsMounts.splitlines()

for pathToNFSMount in nfsMounts:
    signal.signal(signal.SIGALRM, alarm_handler)
    signal.alarm(TIMEOUT)

    try:
        try:
            proc = subprocess.call('stat '+pathToNFSMount, shell=True, stderr=subprocess.PIPE, stdout=subprocess.PIPE)

            if proc != 0:
                raise Exception('Stale')

            contents = scandir(pathToNFSMount)
            file = contents.next()

            signal.alarm(0)
        except StopIteration:
            if not os.path.ismount(pathToNFSMount):
                raise Exception('Not mounted')
        except Alarm:
            raise Exception('Timeout')
    except Exception as e:
        signal.alarm(0)
        print('Remounting: {}'.format(pathToNFSMount))
        os.system('umount -l {}; mount {}'.format(pathToNFSMount, pathToNFSMount))

    print('{} : OK'.format(pathToNFSMount))