Install required packages for Zabbix server setup on CentOS 7:

yum install -y mariadb mariadb-server php php-mysql httpd

Enable and start the MariaDB service:

systemctl enable mariadb
systemctl start mariadb
mysql_secure_installation

Secure the MariaDB enstallation by setting a root password, removing anonymous users, and deleting the test database.

Create a dedicated database and user for Zabbix:

mysql -uroot -p'your_password' -e "CREATE DATABASE zabbix_db CHARACTER SET utf8 COLLATE utf8_bin;"
mysql -uroot -p'your_password' -e "GRANT ALL PRIVILEGES ON zabbix_db.* TO 'zabbix_user'@'%' IDENTIFIED BY 'secure_pass';"

Verify database creation:

mysql -uzabbix_user -psecure_pass -e "SHOW DATABLES;"

Start the Apache web server and check open ports:

systemctl start httpd
netstat -tulpn | grep -E ':80|:3306'

Add the Zabbix repository and install server components:

rpm -Uvh http://repo.zabbix.com/zabbix/3.4/rhel/7/x86_64/zabbix-release-3.4-2.el7.noarch.rpm
yum install -y zabbix-server-mysql zabbix-web-mysql zabbix-get

Import the Zabbix database schema:

cd /usr/share/doc/zabbix-server-mysql-3.4.3/
zcat create.sql.gz | mysql -uroot -p'your_password' zabbix_db

Configure the Zabbix server database connection in /etc/zabbix/zabbix_server.conf:

DBHost=localhost
DBName=zabbix_db
DBUser=zabbix_user
DBPassword=secure_pass

Set the PHP timezone in /etc/httpd/conf.d/zabbix.conf:

php_value date.timezone Asia/Shanghai

Enable and start the Zabbix server service:

systemctl enable zabbix-server
systemctl start zabbix-server
systemctl restart httpd

Access the Zabbix web interface at http://server_ip/zabbix/setup.php to complete installation.

Configure SNMP monitoring for network devices:

yum install -y net-snmp net-snmp-utils

Edit /etc/snmp/snmpd.conf with community string settings:

com2sec readonly  default       monitor_community
group   MyROGroup v2c           readonly
view    all       included   .1
access  MyROGroup ""      any       noauth    exact  all    none   none

Test SNMP connectivity:

snmpwalk -v2c -c monitor_community localhost .1.3.6.1.2.1.1.1

Monitor Nginx service status with custom Zabbix agent checks. First, configure the agent to allow custom parameters in /etc/zabbix/zabbix_agentd.conf:

UnsafeUserParameters=1
Include=/etc/zabbix/zabbix_agentd.d/

Create a script to check Nginx availability:

cat > /etc/zabbix/zabbix_agentd.d/nginx_check.conf << 'EOF'
UserParameter=nginx.alive,curl -s -o /dev/null -w "%{http_code}" http://localhost/ | grep -c '^200$'
EOF

Restart the agent and test locally:

systemctl restart zabbix-agent
zabbix_get -s 127.0.0.1 -k nginx.alive

Enable Nginx status module for detailed metrics by adding to /etc/nginx/nginx.conf:

server {
    listen 127.0.0.1:80;
    location /nginx_status {
        stub_status on;
        access_log off;
        allow 127.0.0.1;
        deny all;
    }
}

Create a comprehensive monitoring script at /usr/local/bin/nginx_monitor.sh:

#!/bin/bash
PORT=${1:-80}
METRIC=$2

case $METRIC in
    active)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk '/Active/ {print $NF}'
        ;;
    reading)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk '/Reading/ {print $2}'
        ;;
    writing)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk '/Writing/ {print $4}'
        ;;
    waiting)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk '/Waiting/ {print $6}'
        ;;
    accepts)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk 'NR==3 {print $1}'
        ;;
    handled)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk 'NR==3 {print $2}'
        ;;
    requests)
        curl -s "http://127.0.0.1:$PORT/nginx_status" | awk 'NR==3 {print $3}'
        ;;
esac

Define the Zabbix agent parameter:

echo 'UserParameter=nginx.stats[*],/usr/local/bin/nginx_monitor.sh $1 $2' > /etc/zabbix/zabbix_agentd.d/nginx_stats.conf

Test the metric collection:

zabbix_get -s 127.0.0.1 -k "nginx.stats[80,active]"

Create a custom Zabbix template for Nginx monitoring through the web interface:

1. Navigate to Configuration → Templates → Create template
2. Add items for each Nginx metric using the nginx.stats[] key
3. Configure triggers based on metric thresholds
4. Design graphs to visualize Nginx performance data
5. Apply the template to monitored hosts

For TCP connection monitoring, implement a script to track connection states:

cat > /usr/local/bin/tcp_connections.sh << 'EOF'
#!/bin/bash
STATE=$1
ss -ant | awk 'NR>1 {count[$1]++} END {print count["'$STATE'"]+0}'
EOF
chmod +x /usr/local/bin/tcp_connections.sh
echo 'UserParameter=tcp.conn[*],/usr/local/bin/tcp_connections.sh $1' > /etc/zabbix/zabbix_agentd.d/tcp_monitor.conf