Script to run a local script remotely only if remote server is reachable

Today I'd like to share a script with you all which all run a local script on a remote server only if the server is reachable via ping. In linux we can count the number of pings we want to send to the server & we'll get an exit status almost immediately. In Solaris we do not have the option of sending a count & if we wait for the default value of 20 seconds for a ping to time out then we'll end up with a very slow script. The work around for this to change the default time out value. The script I use in this article has a ping timeout value of 2 seconds. The remote execution of the local script is carried out by using "bash -s" in the ssh session.

Here is the script:

#!/usr/bin/bash

################################################################
#Purpose: run automount check script on Linux/Solaris servers  #
#date: 12/01/2017                                              #
################################################################

host_list=${1}

##cleaan error server list##
>/export/home/`whoami`/ping_error.txt
>/export/home/`whoami`/automount_hung.txt

##check that server list exists##

if [ $# != 1 ] ; then
        echo "script usage: $0 <server list>"
        exit
fi

for name in `cat $host_list`
do

##check that host is reachable##

ping ${name} 2 &> /dev/null

if [ $? -eq 0 ] ; then
        OS_TYPE=$(ssh -o StrictHostKeyChecking=no -q ${name} 'uname -s')



        if [ $OS_TYPE == "Linux" ] ; then

                ##check if automount is hung##
                AUTO_HUNG="ps -eLo pid,pgrp,lwp,comm,wchan|grep autofs4_wait | grep -v automount"
                ssh ${name} ${AUTO_HUNG} >> /dev/null
                        if [ $? -eq 1 ] ; then
                                ssh -o StrictHostKeyChecking=no -q ${name}  "bash -s" < /export/home/ssuri/automount_check.sh
                        else
                                echo "autoFS service is hung on server ${name}"
                                echo "autoFS service is hung on server ${name}" >>  /export/home/`whoami`/automount_hung.txt
                        fi

        else
                ssh -o StrictHostKeyChecking=no -q ${name} "bash -s" < /export/home/ssuri/automount_check_solaris.sh
        fi
else
        echo "could not connect to server ${name}"
        echo "could not connect to server ${name}" >> /export/home/`whoami`/ping_error.txt
fi

echo -e "------------------------------- \n"

done

echo -e "------------------------------- \n\n"
echo "list of unreachable servers /export/home/`whoami`/ping_error.txt"
echo "list of servers where automount was hung is /export/home/`whoami`/automount_hung.txt"


The script being run remotely automount_check, checks for NFS and auto mount file systems to make sure that they are & can be mounted correctly & in read/write mode. Here is the script:

#!/bin/bash

##############################################
#Purpose: check for automount file systmes.  #
#date: 12/01/2017                            #
##############################################

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


echo -e  "$YELLOW Checking automount file systems on server $(hostname) $NC"

##get automount map file names##

cat /etc/auto.master| grep ^/ | egrep -v '/etc/auto.common|/etc/auto.unix|/etc/auto.ots|/etc/auto.export_home|/etc/auto.misc' | awk '{print $2}' >> /tmp/map_list


for i in `cat /tmp/map_list`; do cat $i | awk '{print $1}'; done >> /tmp/mount_list
cat /etc/fstab | grep nfs | awk '{print $2}' >> /tmp/mount_list
#cat /etc/vfstab | grep nfs | awk '{print $3}' >> /tmp/mount_list

##loop through autmount maps and nfs file systems in fstab file ##

for fs_name in `cat /tmp/mount_list`
do

#FS_name=$(cat $map_name | awk '{print $1}')

echo "checking file system: $fs_name"
cd $fs_name

##make sure autoFS mounts as nfs or cifs##

FS_type=$(df -hT . | awk 'NR==3 {print $1}')

if [ $FS_type == "nfs" ] || [ $FS_type == "cifs" ] ; then
        echo -e $GREEN"$fs_name is of type $FS_type and is  mounted correctly$NC"
else
        echo -e "$RED $fs_name is mounted correctly on $(hostname). Please check $NC"
fi

##check that FS is writable##

sudo touch testfile
if [ $? -eq 0 ] ; then
        echo -e "$GREEN $fs_name mounted on $(hostname) is writable $NC"
else
        echo -e "$RED $fs_name is not writable on $(hostname). Please check $NC"
fi
sudo rm testfile

cd

done

rm /tmp/map_list
rm /tmp/mount_list

I wrote it for doing some post checks after a network activity involving NAS shares just to make sure that everything was normal after the completion of the activity.