This is a question about your opinion on a script I wrote.

At my workplace I wrote a bash-script to execute commands on Linux-Systems (redhat). Since we got Ansible and Puppet nobody was interessted in the script. And to be true: if you got Ansible or Puppet and you are working in a team, it isnt advised to use such a solution... BUT (and thats why I want to post it here and ask for your opinion/improvements on it) if you just want to manage a few Linux hosts and dont want to buy any licence etc. this script may help you out.

the script is called "rotator" and it works like this:

It takes a serverlist and a functionfile. It breaks the Serverlist up into a given maximum number of tmp-lists and executes the commands in the functionfile in the background. Then it waits for all the parallel processes to finish. At the end it checks if all the hosts were visited.

code of rotator.sh:

\#!/bin/bash

usage ()
{
echo ""
echo ""
echo ""
echo "ERROR: $1"
echo ""
echo "You need to provide a serverlist and a"
echo "function file as parameter."
echo "e.g.: sh check_rpm.sh \<server.list\> \<funktions-file.sh\>"
echo "note that the master pushes the config to the client mashines"
echo ""
echo ""
exit 1
}

if \[\[ $# -eq 0 || "$#" == "-h" || "$#" == "--help" || "$#" == "-?" \]\]
then
usage "missing parameter"
exit 1
fi

\######################

# Variablendeklaration

\######################

basedir=$(dirname $0)
hosts=$(cat $1)
funcfile=$2
myhostname=$(hostname -a)
maxlists=100
i=0
j=0
templist=${basedir}/tmp/templist${j}

num=$(cat $1 | wc -l)
length=0
divisor=1

\###################################

# determine num of temp-lists

\###################################

if \[\[ num -gt $maxlists \]\]
then
length=$((num/$maxlists))
((length++))
else
length=1
fi

\######################################

# delete existing old temp lists

\######################################

if \[ ! -z "$(ls -A tmp)" \];
then
rm ./tmp/\*
fi

\######################

# create temp lists

\######################

echo "cutting hostlist"

for host in $hosts;
do
if \[\[ ! "${host^^}" == "${myhostname^^}" \]\]
then
echo $host \>\> $templist
((i++))
fi

if \[\[ $i -eq $length \]\]
then
((j++))
templist=${basedir}/tmp/templist${j}
i=0
fi
done

if \[\[ $j -eq 0 \]\]
then
j=1
fi

\##################################################

# start func-file for all lists and remember PID

\##################################################

k=0
for ((i=0;i\<$j;i++));
do
sleep 0.2
sh $funcfile ${basedir}/tmp/templist${i} &
pids\[${k}\]=$!
((k++))
done

\######################################

# wait till all processes terminate

\######################################

echo "waiting till all processes are done"

for pid in ${pids\[\*\]};
do
wait $pid
done

\#######################

# cleanup temp lists

\#######################

for ((i=0;i\<$j;i++));
do
rm -f ${basedir}/tmp/templist${i}
done

\##########################################

# determine if all hosts were visited

\##########################################

echo "determine if all hosts were visited..."

checkhosts=$(cat tmp/check.list)
done=false
absenthosts=""

for host in $hosts
do
for server in $checkhosts
do
host=$(echo ${host^^})
server=$(echo ${server^^})
if \[\[ "$host" == "$server" \]\]
then
done=true
fi
done

if \[\[ "$done" == "false" \]\]
then
absenthosts+="$host "
else
done=false
fi
done

rm tmp/check.list

\############################################

# tell user which hosts were not visited

\############################################

echo "the following hosts werent visited and need to be handled manually"
echo ""

for host in $absenthosts
do
echo "$host"

done

**# END OF SCRIPT**

Here is an example of a function-file:

\#!/bin/bash

# 

# 

# 

# ================||

# PLEASE BE AWARE ||

# ================||

# Add the code, which should be executed within the marked space

# instead of using "ssh" use $SSHOPTS

# 

# 

hosts=$(cat $1)
SSHOPTS="ssh -q -o BatchMode=yes -o ConnectTimeout=10"

for host in $hosts
do
$SSHOPTS $host "hostname" \>\> /opt/c2tools/serverliste_kontrollskripten/rotator/tmp/check.list

# 

# MARK: add code after this mark

# 

# 

# MARK: add code before this mark

# 

done

**# END OF SCRIPT**

I would say, that if you combine the rotator with cron-job, you could more or less use it as an free alternative to puppet or ansible, with the bonus that you can write the function-files in the bash scripting language.

Please share your opinion

The script runs, but could be improved