NFS automount, Linux (CentOS) version

** NOTE: This version is obsoleted! The latest version can be found here.

Last summer I posted a script that would repeatedly (via cron) check on a availability and status of a NFS mount, and attempt to keep it mounted if possible. That script was written for (Free)BSD. Below is a slightly modified version that runs on Linux (in this case, CentOS).

#!/bin/sh

SHELL=/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin

# remote system name
remotesystem=sunrise.externalized.net

# remote share name
remoteshare=/nfs4exports/minecraft-backups

# local mount point
mountpoint=/bak/remote

# file to indicate local mount status
testfile=$mountpoint/.minecraftbackups

# command locations
pingcmd=/bin/ping
showmountcmd=/usr/sbin/showmount
grepcmd=/bin/grep
mountcmd=/bin/mount
umountcmd=/bin/umount
statcmd=/usr/bin/stat

# --- end variables ---

# make sure the mountpoint is not stale
testvar=`${statcmd} ${mountpoint} 2>&1 | ${grepcmd} "Stale"`

if [ "${testvar}" != "" ]; then
   #result not empty: mountpoint is stale; remove it
   ${umountcmd} -f ${mountpoint}
fi

# ping the remote system (2 sec timeout)
${pingcmd} -w2 -c1 -q ${remotesystem} > /dev/null 2>&1

if [ "$?" -eq "0" ]; then
   
   # server is available so query availability of the remote share; not empty is OK
   offsiteshare=`${showmountcmd} -e ${remotesystem} | ${grepcmd} "${remoteshare}"`

   # make sure the local mountpoint is not active
   localmount=`${mountcmd} | ${grepcmd} "${mountpoint}"`

   if [ "${offsiteshare}" != "" ] ; then
      if [ ! -e ${testfile} ] ; then
         if [ "${localmount}" = "" ] ; then
            ${mountcmd} -w -t nfs ${remotesystem}:${remoteshare} ${mountpoint}
         fi
      fi
   fi
fi

exit 0