Compiling nrpe in HPUX 11.31

Ok, we got our brand new HP rx8640 servers running HPUX 11.31 and needed to monitor them with nagios. As check_by_ssh turned to be a lot slower than NRPE+SSL on our former Solaris servers, we defined as policy that every server under our control should be monitored using NRPE.

Found that someone already did the nasty work of compiling it and even created a current depot (software package in HPUX terms) that works with 11.31. There are a couple of drawbacks though, it runs using inetd which is not practical when you run a lot of frequent checks and it’s compiled without the “–enable-command-args” and this last bit makes it useless for our needs.

Using Olivier’s build notes, slightly modified,  I’ve built NRPE with “–enable-command-args” and created a script to start it as a standalone service rather than using inetd.

Here’s the process:

TCP Wrappers  note

According to Olivier’s notes, he used the tcpwrapper’s source included with SSHD (is it Openssh?) located at /opt/ssh/src/tcp_wrappers_7.6-ipv6.4. To be able to build it, I had to modify the Makefile, adding “-DUSE_GETDOMAIN” to the BUGS macro definition. Otherwise, I was getting the following error:

/usr/ccs/bin/ld: Unsatisfied symbols: yp_get_default_domain (code)

Procedure:

vi Makefile <-- add "-DUSE_GETDOMAIN" to BUGS macro definition
make REAL_DAEMON_DIR=/tmp hpux
ls -l libwrap.a

The thing is, it didn’t work…. After building it and using the generated libwrap.a at NRPE compilation time, I was getting:

-------------
utils.c:
ld: Unsatisfied symbol "fromhost" in file nrpe.o
1 errors.
*** Error exit code 1
Stop.
*** Error exit code 1
Stop.
-------------

Going back with stock libwrap on HPUX, I only needed to define a missing variable for it in nrpe.c (rfc931_timeout)

Patching/modifying NRPE

tar xvf nrpe-2.12.tar
cd nrpe-2.12
vi src/nrpe.c

/* Add syslog facilities that are missing in HPUX */
#define LOG_AUTHPRIV (10<<3) /* security/authorization messages (private) */
#define LOG_FTP (11<<3) /* ftp daemon */
/* Adding variable missing in libwrap */
int rfc931_timeout=15;

NRPE configuration

PATH="$(cat /etc/PATH):/usr/local/bin" ./configure --prefix=/opt/nagios \
   --with-ssl-inc=/opt/openssl/include --with-ssl-lib=/opt/openssl/lib/hpux32 \
   --enable-command-args

Compilation & Installation

make
make install
mkdir /opt/nagios/etc
cp sample-config/nrpe.cfg /opt/nagios/etc/

Init script

I created a init script to start NRPE as a service, but apparently wordpress doesn’t allow any arbitrary file to be uploaded. I’ll upload it as soon as possible.

Update: As I’m unable to post files, I’ll have to include the script inline…. For this to work you need two files, one for “enablement” of the service and the control script.

/etc/rc.config.d/nrpe

# Nagios Remote Plugin Executor 
ENABLE_NRPE=1

/sbin/init.d/nrpe

#!/usr/bin/bash
# Ciro Iriarte - May 5th, 2010
# some parts taken from SuSE's NRPE init script and xntpd init from HPUX

if [ -f /etc/rc.config ] ; then
        . /etc/rc.config
else
        echo "ERROR: /etc/rc.config defaults file MISSING"
fi

rval=0
set_return() {
        x=$?
        if [ $x -ne 0 ]; then
                echo "EXIT CODE: $x"
                rval=1  # always 1 so that 2 can be used for other reasons
        fi
}

NRPE_BIN=/opt/nagios/bin/nrpe
test -x $NRPE_BIN || { echo "$NRPE_BIN not installed";
        if [ "$1" = "stop" ]; then exit 0;
        else exit 5; fi; }

# Check for existence of needed config file and read it
NRPE_CONFIG=/opt/nagios/etc/nrpe.cfg
test -r $NRPE_CONFIG || { echo "$NRPE_CONFIG not existing";
        if [ "$1" = "stop" ]; then exit 0;
        else exit 6; fi; }

case "$1" in
        start_msg)
                echo -n "Starting Nagios NRPE "
        ;;
        stop_msg)
                echo -n "Shutting down Nagios NRPE "
        ;;
        start)
                if [ $ENABLE_NRPE -eq 1 ]
                then
                        $NRPE_BIN -c $NRPE_CONFIG -d
                        set_return
                        ## $0 start_msg
                        ##if [ $rval -eq 0 ];then echo -e "\t\t[ OK ]";else echo -e "\t\t[ ERR ]";fi 
                else
                        rval=2
                fi
        ;;
        stop)
                if [ $ENABLE_NRPE -ne 1 ]
                then
                        rval=2
                else
                        PID=$(ps -el | awk '( ($NF ~ /nrpe/) && ($4 != mypid) && ($5 != mypid)) { print $4 }' mypid=$$)
                        ##$0 stop_msg
                        if [[ -n $PID ]];then
                                if kill $PID 2> /dev/null; then
                                        echo -e "\tService stopped"
                                else
                                        if [ $(ps -fp $PID|grep -v COMMAND|wc -l) -gt 0 ]
                                        then
                                                set_return
                                                ##echo -e "\t\t[ ERR ]"
                                                echo -e "\tCouldn't stop NRPE"
                                        fi
                                fi
                        else
                                set_return
                                ##echo -e "\t\t[ ERR ]"
                                echo -e "\tUnable to stop NRPE, cannot find PID"
                        fi
                fi
        ;;
        restart)
                $0 stop
                $0 start
        ;;
        *)
                echo "Usage: $0 {start|stop|restart}"
                rval=1
        ;;
esac
exit $rval

After creating those files you’ll need to make links to the control script to be able to start and stop on boot and shutdown

/sbin/rc1.d/K500nrpe -> /sbin/init.d/nrpe
/sbin/rc3.d/S999nrpe -> /sbin/init.d/nrpe

Those were the missing bits…