If you simply run your script from command line, does it work as it should on all PHP versions?
Yes - execution of the PHP UserParameter script works just fine from the command line as a PHP invocation. The following document fragment for one of my SourceForge projects notes this issue:
=========================
It appears that Zabbix, of any release, using PHP for UserParameter scripts may encounter a breaking point if the version of PHP is 5.3.3 (or < 5.4). Using such a script will cause the zabbix_agentd process to hang. For implementors of Zabbix-HDD, there are three alternatives:
1. install PHP >= 5.4
2. don't use PHP based UserParameter scripts (eg; stick to (Unix) shell scripts)
3. use a “sneaky proxy” by putting the PHP UserParameter script under Apache (HTTPD) with built-in PHP support and using curl to invoke the PHP UserParameter script and successfully process it, such as
1. UserParameter=hw.disk.discovery,/usr/bin/curl --raw --silent http://localhost/zabbix-php/<script filename>
= = = = = = = = = = = = = = = = =
Apache configuration used:
Alias /zabbix-php "/var/www/html/zabbix-php"
<Directory "/var/www/html/zabbix-php/">
Allow from all
</Directory>
AddType application/x-httpd-php .php
<FilesMatch \.php$>
SetHandler application/x-httpd-php
</FilesMatch>
Two simple PHP scripts to use for testing (“stdout.tester.php”, ”stdout.tester2.php”)
<?php
echo "strftime: " . strftime("%c");
exit;
?>
<?php
$lastline=exec("cat /proc/partitions",$ProcPartARRAY,$RC);
$count=fwrite(STDOUT,print_r($ProcPartARRAY));
exit;
?>
Sample result (“local.php.test” => “stdout.tester.php”):
zabbix_get -s 127.0.0.1 -k local.php.test
strftime: Sat Aug 5 01:49:38 2017
=========================
NOTE: this issue with PHP-5.3.3 does not appear to affect the Zabbix "front-end" (web pages). Only the "child process" environment that is created/used for UserParameter scripts.
When Zabbix hangs with PHP-5.3.3 is there any hanging or zombie processes related to your script?
Zabbix receives SIGCHLD while doing read() meaning that script terminated, but read() does not unblock meaning that file descriptor Zabbix is reading from wasn't closed by all processes having it open. Then finally read() is interrupted by SIGALRM, Zabbix tries to kill() child and blocks in waitpid(). Maybe it's a sort of misbehaviour on PHP side, but Zabbix should definitely be robust enough to handle it. waitpid() must be executed within timeout.
No zombie processes found.
List of running agentd tasks:
=====================================
zabbix 2490 1 0 15:46 ? 00:00:00 /usr/local/sbin/zabbix_agentd zabbix 2491 2490 0 15:46 ? 00:00:01 /usr/local/sbin/zabbix_agentd: collecto r [idle 1 sec] zabbix 2492 2490 0 15:46 ? 00:00:00 /usr/local/sbin/zabbix_agentd: listener #1 [waiting for connection] zabbix 2493 2490 0 15:46 ? 00:00:00 /usr/local/sbin/zabbix_agentd: listener #2 [waiting for connection] zabbix 2494 2490 0 15:46 ? 00:00:00 /usr/local/sbin/zabbix_agentd: listener #3 [waiting for connection] zabbix 2495 2490 0 15:46 ? 00:00:01 /usr/local/sbin/zabbix_agentd: active c hecks #1 [idle 1 sec] postfix 3460 1964 0 17:21 ? 00:00:00 pickup -l -t fifo -u root 3512 2405 0 17:29 pts/1 00:00:00 vi zabbix_agentd.conf root 3523 2403 0 17:30 pts/0 00:00:00 zabbix_agentd -t local.php.test root 3524 3523 0 17:30 pts/0 00:00:00 /usr/bin/php -f /var/tmp/stdout.tester. php
=====================================
top (partial) output
=====================================
top - 17:49:58 up 2:09, 4 users, load average: 0.08, 0.07, 0.02
Tasks: 163 total, 1 running, 161 sleeping, 1 stopped, 0 zombie
Cpu(s): 0.7%us, 0.4%sy, 0.0%ni, 98.5%id, 0.4%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 1020052k total, 895756k used, 124296k free, 50088k buffers
Swap: 2064380k total, 8k used, 2064372k free, 237096k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7 root 20 0 0 0 0 S 1.8 0.0 0:02.79 events/0
2366 root 20 0 292m 13m 9912 S 1.8 1.3 0:00.97 gnome-terminal
2491 zabbix 20 0 78620 1096 592 S 1.8 0.1 0:01.93 zabbix_agentd
3997 root 20 0 17072 1140 828 R 1.8 0.1 0:00.04 top
1 root 20 0 21388 1556 1236 S 0.0 0.2 0:00.75 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root RT 0 0 0 0 S 0.0 0.0 0:00.00 migration/0
4 root 20 0 0 0 0 S 0.0 0.0 0:00.33 ksoftirqd/0
5 root RT 0 0 0 0 S 0.0 0.0 0:00.00 stopper/0
6 root RT 0 0 0 0 S 0.0 0.0 0:00.04 watchdog/0
=====================================
Terminal output from "stalled" agent task
=====================================
[root@centos62b ~]# zabbix_agentd -t local.php.test local.php.test [cursor]
Other agentd tasks are periodically running
Hung agentd task finally times out
==================================
zabbix_agentd -t local.php.test local.php.test [m|ZBX_NOTSUPPORTED] [Timeout while executing a shell script.]
Running the same script with the same version of Zabbix on the same client machine BUT
with a newer PHP (v5.6.32) - everything works just fine.
Hm, if Zabbix times out, then everything on Zabbix side works as expected, doesn't it?
I would recommend to look for solution of PHP problem on our forum or IRC channel. Maybe it's even more PHP-related, then Zabbix-related. Or a weird selinux issue...
Closing as Won't Fix.
I have already established two resolutions: a) upgrade php to >= v5.4, b) run php UserParameter scripts under Apache (HTTPD), via "curl", using its php module to execute the PHP UserParameter script(s).
What would really be helpful for all is to update Zabbix Manual UserParameter sections to indicate the possibility of problems/issues if the PHP invoked by zabbix_agentd is version 5.3.3 and recommending installing PHP >= v5.4. This would allow other Zabbix implementers to make an informative decision about using PHP for Zabbix UserParameter scripts. It would also expand the scope of "external programs" possibly used with/by Zabbix.
I'm not sure there is a suitable place in official Zabbix documentation (and the use case seems a bit too specific, we try to keep docs short and focused) but you are welcome to share your findings on zabbix.org 