Trivial Let's count number of running apache processes by using pgrep:
$ pgrep -ca apache 6
Let's double check:
$ ps axuwww | grep apache root 721 0.0 0.2 379608 33972 ? Ss Mar06 0:26 /usr/sbin/apache2 -k start vl 27738 0.0 0.0 14000 984 pts/10 S+ 17:47 0:00 grep --color=always apache www-data 28946 0.0 0.0 379680 10924 ? S 06:25 0:00 /usr/sbin/apache2 -k start www-data 28947 0.0 0.0 379680 10924 ? S 06:25 0:00 /usr/sbin/apache2 -k start www-data 28948 0.0 0.0 379648 9668 ? S 06:25 0:00 /usr/sbin/apache2 -k start www-data 28949 0.0 0.0 379648 9668 ? S 06:25 0:00 /usr/sbin/apache2 -k start www-data 28950 0.0 0.0 379680 10924 ? S 06:25 0:00 /usr/sbin/apache2 -k start
We can see that we have 6 processes running, matching command-line pattern "apache".
Let's use zabbix_agentd to get the same thing:
$ sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf -t proc.num[,,,apache2] proc.num[,,,apache2] [u|8]
Why 8? It appeared it also counts itself (2 times) as its command-line contains the same pattern, in 2 files:
/proc/<OWNPID>/cmdline /proc/thread-self/cmdline
In the code we already filter out /proc/self but this is not enough as it points to the corresponding PID file. So what we need is follow the link and ignore the PID that it points to.
The attached patch takes care of it. After applying it:
$ sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf -t proc.num[,,,apache2] proc.num[,,,apache2] [u|6]
we get the correct value.
In addition, the patch makes agent ignore any non-numeric entries in /proc.
P. S. This happens only when calling zabbix_agentd with -t (test mode).
