Frontend HTTP error 500

[markfree]

I've set a new installation of Zabbix 5.4 from sources using:

./configure --enable-server --enable-agent --with-mysql --enable-ipv6 --with-net-snmp --with-libcurl --with-libxml2 --with-openssl --with-ldap --with-ssh

Initially everything went well. I was able to start the server with no errors.
Then, I copied Zabbix UI to "/var/www/html".

cp -a ./ui /var/www/zabbix/

When I tried to open Zabbix's frontend I got an "HTTP ERROR 500".

Looking at "/var/log/httpd/error_log", it shows me the error bellow.

[Sun Nov 21 20:03:12.845099 2021] [:error] [pid 5938] [client 192.168.1.3:2511] PHP Parse error: syntax error, unexpected ':', expecting ';' or '{' in /var/www/html/zabbix/include/classes/user/CWebUser.php on line 48

This error line points to this code excerpt:

/**
* Tries to login a user and populates self::$data on success.
*
* @param string $login user login
* @param string $password user password
*
* @throws Exception if user cannot be logged in
*
* @return bool
*/
public static function login(string $login, string $password): bool {    /** << ACTUAL LINE 48*/
try {
self::$data = API::User()->login([
'username' => $login,
'password' => $password,
'userData' => true
]); 

That's unusual to me.
Any idea on what that is?

[tim.mooney]

This is almost certainly a httpd configuration issue, probably relating to PHP.

How are you processing PHP? mod_php7, or PHP-FPM?

Show us the virtual host configuration, and if PHP is configured in a different file, show us the httpd config for PHP.

You can obfuscate any sensitive hostnames or IP addresses, if you need.

Also, have you verified that you have all the required PHP extensions loaded?

[Glencoe]

Also, check your PHP version. It must be 7.2.5+.

[markfree]

This is more of an experimental installation.

Show us the virtual host configuration, and if PHP is configured in a different file, show us the httpd config for PHP.

What virtual host configuration do you mean?

I installed PHP 7.3 FPM.

# systemctl status rh-php73-php-fpm
● rh-php73-php-fpm.service - The PHP FastCGI Process Manager
Loaded: loaded (/usr/lib/systemd/system/rh-php73-php-fpm.service; enabled; vendor preset: disabled)
Active: active (running) since Mon 2021-11-22 10:22:14 -03; 10min ago
Main PID: 32438 (php-fpm)
Status: "Processes active: 0, idle: 5, Requests: 0, slow: 0, Traffic: 0req/sec"
CGroup: /system.slice/rh-php73-php-fpm.service
├─32438 php-fpm: master process (/etc/opt/rh/rh-php73/php-fpm.conf)
├─32439 php-fpm: pool www
├─32440 php-fpm: pool www
├─32441 php-fpm: pool www
├─32442 php-fpm: pool www
└─32443 php-fpm: pool www

Nov 22 10:22:14 centos7 systemd[1]: Starting The PHP FastCGI Process Manager...
Nov 22 10:22:14 centos7 systemd[1]: Started The PHP FastCGI Process Manager.

# grep -v "^\;" /etc/opt/rh/rh-php73/php-fpm.conf | grep .
include=/etc/opt/rh/rh-php73/php-fpm.d/*.conf
[global]
pid = /var/opt/rh/rh-php73/run/php-fpm/php-fpm.pid
error_log = /var/opt/rh/rh-php73/log/php-fpm/error.log
daemonize = yes

PHP configuration has has a zabbix rpmsave file from a previous package installation.

# ls -lah /etc/opt/rh/rh-php73/php-fpm.d/zabbix.conf.rpmsave
-rw-r--r-- 1 root root 620 Nov 21 10:14 /etc/opt/rh/rh-php73/php-fpm.d/zabbix.conf.rpmsave

This "zabbix.conf" file points to a "zabbix.sock" that does not exist.

# grep listen /etc/opt/rh/rh-php73/php-fpm.d/zabbix.conf.rpmsave
listen = /var/opt/rh/rh-php73/run/php-fpm/zabbix.sock

I'm not sure it is doing anything.

Current modules are:

# php -m
[PHP Modules]
bcmath, bz2, calendar, Core, ctype, curl, date, dom, ereg, exif, fileinfo, filter, ftp, gd, gettext, gmp, hash, iconv, json, ldap, libxml, mbstring, mhash, mysql, mysqli, openssl, pcntl, pcre, PDO, pdo_mysql, pdo_sqlite, Phar, readline, Reflection, session, shmop, SimpleXML, sockets, SPL, sqlite3, standard, tokenizer, wddx, xml, xmlreader, xmlwriter, xsl, zip, zlib

[tim.mooney]

I'm sorry I wasn't clear. When I said "virtual host", I meant your web server virtual host, i.e your apache httpd configuration, especially the stuff inside the <Server> block.

[markfree]

I think I might have messed up this installation. I might have not updated PHP and its dependencies correctly. Also, Zabbix UI copy was probably misplaced.
So I decided to start all over again.
I created a fresh CentOS VM and started installation.

This time, instead of installing centos-release-scl, I decided to install PHP 7.4 from Remi's repository.
I followed this steps (not necessarily in this order).

yum install -y epel-release yum-utils

rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-4.noarch.rpm
yum install -y mysql-community-server
yum -y upgrade
systemctl start mysqld
MYSQLTEMPPASS=`grep 'temporary password' /var/log/mysqld.log | awk '{print $13}'`
mysql -uroot -p$MYSQLTEMPPASS
# AJUSTED ROOT PASS AND CREATED ZABBIX DB, then
mysql_secure_installation
mysql -uzabbix -pzabbix zabbix < database/mysql/schema.sql
mysql -uzabbix -pzabbix zabbix < database/mysql/images.sql
mysql -uzabbix -pzabbix zabbix < database/mysql/data.sql


yum install -y http://rpms.remirepo.net/enterprise/remi-release-7.rpm
yum-config-manager --enable remi-php74
yum install -y php php-opcache php-mcrypt php-gd php-curl php-mysqlnd php-bcmath php-mbstring php-xml php-ldap


rh-php73-php-ldap
yum install -y gcc gcc-c++ mysql-devel libxml2 libxml2-devel net-snmp net-snmp-utils net-snmp-devel libcurl libcurl-devel libssh2-devel openldap-devel libevent libevent-devel


groupadd --system zabbix
useradd --system -g zabbix -d /usr/lib/zabbix -s /sbin/nologin -c "Zabbix Monitoring System" zabbix

./configure --enable-server --enable-agent --with-mysql --enable-ipv6 --with-net-snmp --with-libcurl --with-libxml2 --with-openssl --with-ldap --with-ssh2
make install


mkdir /var/www/zabbix/
cp -a ./ui/* /var/www/html/zabbix/
systemctl enable httpd
systemctl restart httpd

sed -i 's|post_max_size = 8M|post_max_size = 16M|' /etc/php.ini
sed -i 's|max_execution_time = 30|max_execution_time = 300|' /etc/php.ini
sed -i 's|max_input_time = 60|max_input_time = 300|' /etc/php.ini


firewall-cmd --zone=public --add-service=http --permanent
sed -i 's|SELINUX=enforcing|SELINUX=disabled|' /etc/selinux/config
reboot

Oddly enough, after quite some work, the frontend's installation could not create the configuration file, but it was offered as a download.
I then copied the new conf file to its "/var/www/html/zabbix/conf/", restarted HTTPD and everything started working.
Finally!

[tim.mooney]

I'm surprised you were able to get Zabbix server 5.4 to build on CentOS 7 / RHEL 7. Server 5.4 isn't supported on RHEL 7 or CentOS 7, and it requires OpenSSL 1.1.1.

[markfree]

tim.mooney commented
I'm surprised you were able to get Zabbix server 5.4 to build on CentOS 7 / RHEL 7. Server 5.4 isn't supported on RHEL 7 or CentOS 7, and it requires OpenSSL 1.1.1.

It would be nice to have full support for Zabbix 5.4 or higher with CentOS 7 since it still has some years left of official support.

I tried using packages recommended in documentation, but dependencies were not satisfied correctly.

Anyhow, Zabbix configuration is great for instructing us on what it needs to work.
With the documentation by my side, I managed to circumvent OS requirements, mainly PHP upgrade, and install Zabbix 5.4 from sources.
Then, I pointed a previous 5.0 DB to the new installation and it updated correctly.

[reekjohns]

The error is too generic and does not tell you exact problem. What you need is to find out what is the real issue. If your site is serving a Internal Server Error, this can be caused by a number of things, such as:

• Server permission
• Server timeout
• Script timeout
• Errors in .htaccess files
• Exceeded PHP memory limit.
• Or some other Web Server Issues

Normally, a permissions issue on the file (or files) would be one cause of the 500 internal server error. The simple solution is to run chmod 644 on the problem file(s) or chmod 755 on the directories.

$ sudo chmod -R 777 /"your files location"

The best way to debug the error depends upon the server and what’s actually running at the time. Consider some debugging tips to help diagnose and fix common causes of this problem.