Support Center > Knowledgebase > DirectAdmin > Apache Related Information > Automating the removal of apache semaphores with ipcs/ipcrm
Automating the removal of apache semaphores with ipcs/ipcrm
If you routinely need to remove apache semaphores with the ipcs/ipcrm tool, and if you cannot sort out why they keep building up, then using a cronjob to automatically clear them out if they've piled up may help.
UPDATE: DirectAdmin 1.53.0+ now has a hook script which can be called, instead of using a cron. This should provide faster reaction times for a downed service:
https://www.directadmin.com/features.php?id=2101
where you'd use the script below, after confirming the "$service" is "httpd", eg:
if [ "$service" != "httpd" ]; then
exit 1;
fi
inserted just below the #!/bin.sh line.
Else for the cron method, create the script in:
/etc/cron.hourly/ipcs_check
with the contents:
#!/bin/sh
EMAIL=your@email.com
MAX_SEMAPHORES=15
IPCS=/usr/bin/ipcs
IPCRM=/usr/bin/ipcrm
MAIL=/bin/mail
COUNT=`${IPCS} | grep apache | wc -l`
if [ "$COUNT" -le $MAX_SEMAPHORES ]; then
#all is well, there are no semaphore build-ups.
exit 0;
fi
#we have more than MAX_SEMAPHORES, so clear them out and restart Apache.
LIST=/root/sem.txt
${IPCS} | grep apache | awk '{print $2}' > ${LIST}
for i in `cat ${LIST}`; do
{
${IPCRM} -s $i;
};
done;
/etc/init.d/httpd restart
TXT="${COUNT} semaphores cleared for apache for `hostname`"
echo "${TXT}" | ${MAIL} -s "${TXT}" ${EMAIL}
exit 1;
and then chmod the script to 755:
chmod 755 /etc/cron.hourly/ipcs_check
Check your /var/log/cron on each hour, to ensure that crond is running it.
If all is well, then there shouldn't be any issues, and the script will exit with a return code of 0.
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