October 2008 – Not So Frequently Asked Questions

Changing nagios face: nagios nuvola style

Let’s be honest. Nagios has lots of good things. But it also have bad ones: it stores data in non-indexed text files, executes a compiled CGI, configuration files are unconfortable when adding and removing new machines (mainly removing them)… and mainly: it’s ugly. Maybe ugly is not the word… it’s austere, simple, not attractive.

I don’t give a damn (and I’m pretty sure I’m not the only one), because it’s a tool, and it does its work. I’m not here to enjoy watching it, but to warn me when things go wrong, and to explain me why are they going wrong. But in this world, the ones who take decisions and buy things, they frequently look at the appearance, sometimes beyond functionality. Then if you are trying to convince someone to use nagios, you’ll have more chances if it was pretty.

Here is where nagios nuvola style comes, to give nagios another look, very different, and to make it nicer (in the full article you’ll find two screenshots so you can compare). It’s made by the same people that made nagiosql, and although it has a nagiosexchange page, the downloadable file there is corrupt (one css is bad, status.css, and it looks very different). I took it from this website, and you can download it here, too.

Installing it couldn’t be easier. You just copy files inside “html” directory inside your nagios. In a debian, for instance, it’s as easy as:
wget http://tomas.cat/blog/sites/default/files/nagios-nuvola-1.0.3.tar_.gz mkdir nuvola cd nuvola tar zxvf ../nagios-nuvola-1.0.3.tar_.gz cp -a html/* /usr/share/nagios3/htdocs/ cp -a html/stylesheets/* /etc/nagios3/stylesheets/.

And that’s it, you got your look-improved nagios!

That’s how “original” nagios looks:

That’s how it looks with its face changed:

First example of remote pstools execution: winps.sh

Next mission was making scripts to execute pstools remotely. I started make one for each tool, but I found out there was a lot of shared code, so I decided to create an generic script, psexec.sh (honoring pstools), receiving the server and the tool, with its parameters. After that, we should only create a wrapper for every command to make our life easier.

The script must check if file credentials are valid, and asking for others if they aren’t. Once authenticated, it must check if there’s pstools installed or not, and copy them if not.

In the full story you can see the code of psexec.sh and an example wrapper, winps.sh. Keep in mind that they need some files, winvars.sh and cp_pstools.sh in order to work properly, as we saw in the rc=$?

if [ $rc -eq 0 ];then
echo "Default credentials"
elif [ $rc -eq 1 ];then
echo "$? Hola"
echo "Default credentials doesn't authentify. Try others."
read -p "Type username (DOMAIN/user):" user
read -s -p "Type password:" pass
PSCREDENTIALS="--user $user --password $pass"
winexe //$1 "$TOOLS_UNIT:\$TOOLS_DIR\pstools\pslist.exe /accepteula -t" $PSCREDENTIALS
rc=$?
if [ $rc -eq 1 ];then
echo "Credentials error or unit not available (check smbmount errors)" && exit 1
elif [ $rc -eq 99 ];then
echo "There's no pstools, I'll copy them"
$PROGPATH/cp_pstools.sh $1 $user $pass
[ $? -ne 0 ] && echo "There's no pstools and I couldn't copy them." && exit 1
winexe //$1 "d:\scripts\pstools\pslist.exe /accepteula -t" $PSCREDENTIALS
rc=$?
if [ $rc -eq 99 ];then
echo "Pstools are copied, but they don'y work, somethings going on." && exit 1
fi
fi
elif [ $rc -eq 99 ];then
echo "There's no pstools, I'll copy them"
$PROGPATH/cp_pstools.sh $1
[ $? -ne 0 ] && echo "There's no pstools and I couldn't copy them." && exit 1
winexe //$1 "d:\scripts\pstools\pslist.exe /accepteula -t" $PSCREDENTIALS
rc=$?
if [ $rc -eq 99 ];then
echo "Pstools are copied, but they don'y work, somethings going on." && exit 1
fi
fi

Wrapper example: winps.sh
#!/bin/bash


[ $# -ne 1 ] && echo "Error, I need one and only one argument" && exit 1

PROGPATH=echo $0 | /bin/sed -e 's,[\/][^\/][^\/]*$,,'

$PROGPATH/psexec.sh $1 pstools\pslist -t

Automatically copying pstools to the windows server from your linux

Following the path we were… What if we want to use pstools in 50 servers? As an idea, we can creat a shared unit, and make all servers to execute pstools there. But if we have some in some networks, some in some other networks (including DMZ), in a domain or not… Couln’t be an easy way to copy them?

With this purpose I’ve made this little script, doing exactly that: copying pstools to the server we want. First of all it mounts a cifs unit (with smbmount), then copy the files and then umount it.

I’ve made it to be called from other scripts. For instance, if we make a “winps”, we can make it to check if pstools are installed first, and to copy them if they aren’t.

In the full article you can see the code an download the file.

winvars.sh
winvars.sh
#!/bin/bash

TOOLS_DIR=tools TOOLS_UNIT=d CREDENTIALS="/home/user/secretfile" SMBCREDENTIALS="credentials=$CREDENTIALS" PSCREDENTIALS="-A $CREDENTIALS"

Difference between SMBCREDENTIALS and PSCREDENTIALS is the way smbmount and winexe accept them.

cp_pstools.sh
cp_pstools.sh
#!/bin/bash


# We get the script path

PROGPATH=echo $0 | /bin/sed -e 's,[\/][^\/][^\/]*$,,'

# We load our vars

. $PROGPATH/winvars.sh
PSTOOLS_SRC=/home/user/pstools/

RAND_DIR=$1-$RANDOM
[ $# -lt 1 ] && echo "Error, too few parameters" && echo "Use: $0 server [unit]" && exit

[ ! -z "$2" ] && SMBCREDENTIALS="username=$2,password=$3"
mkdir /tmp/$RAND_DIR

smbmount //$1/$TOOLS_UNIT$ /tmp/$RAND_DIR -o $SMBCREDENTIALS
if [ $? -eq 0 ];then

  echo "Default credentials"

else

  echo "Default credentials doesn't authentify. Try others."

  read -p "Type username (DOMAIN/user):" user

  read -s -p "Type password:" pass

  smbmount //$1/$TOOLS_UNIT$ /tmp/$RAND_DIR -o username=$user,password=$pass

  [ $? -ne 0 ] &&  echo "Credentials error or unit not available (check smbmount errors)" && rmdir /tmp/$RAND_DIR && exit 1

fi
mkdir /tmp/$RAND_DIR/$TOOLS_DIR

cp -av $PSTOOLS_SRC /tmp/$RAND_DIR/$TOOLS_DIR/.

smbumount /tmp/$RAND_DIR

rmdir /tmp/$RAND_DIR>