Prioritizing CloudLinux, PHP-FPM, Nginx, MySQL, Apache, cPanel, ModSecurity, and Kernel
Managing a cPanel/Linux server involves routine checks, debugging, logging, and monitoring to ensure the server runs smoothly and efficiently. This guide covers essential commands and techniques to help you maintain your server, identify common errors, and provide solutions.
1. cPanel Management
cPanel Status
Check the status of the cPanel service:
service cpanel status
Restart cPanel Service
Restart the cPanel service:
service cpanel restart
cd /etc/rc.d/init.d
./cpanel restart
cPanel Logs
View the last 100 lines of the cPanel logs:
tail -100 /usr/local/cpanel/logs/error_log
tail -100 /usr/local/cpanel/logs/access_log
Restart Tailwatch (cPanel service)
Restart Tailwatch service:
/scripts/restartsrv_chkservd
2. Apache Management
Apache Status
Check the status and processes of Apache:
ps aux | grep httpd
systemctl status httpd
service httpd status
Restart Apache
Restart Apache with hard restart if needed:
/scripts/restartsrv_httpd --restart --hard
/scripts/restartsrv_httpd
Apache Logs
View the last 100 lines of the Apache error logs:
tail -100 /etc/apache2/logs/error_log
tail -100 /var/log/apache2/error_log
Common Apache Errors and Solutions
Error:
AH00558: httpd: Could not reliably determine the server's fully qualified domain name
Solution:
- Edit the Apache configuration file:
vi /etc/httpd/conf/httpd.conf
- Add the following line:
ServerName localhost
- Restart Apache:
/scripts/restartsrv_httpd
3. MySQL Management
MySQL (MariaDB) Status
Check the status of MySQL/MariaDB:
service mysqld status
systemctl status mysqld
mysqladmin proc status
Restart MySQL
Restart MySQL service:
/scripts/restartsrv_mysql
MySQL Logs
View the last 100 lines of the MySQL error logs:
tail -100 /var/log/mysqld.log
Common MySQL Errors and Solutions
Error:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'
Solution:
- Check if MySQL service is running:
systemctl status mysqld
- Restart MySQL service:
/scripts/restartsrv_mysql
4. PHP-FPM Management
PHP-FPM Status
Check the status of PHP-FPM:
/scripts/restartsrv_cpanel_php_fpm status
Restart PHP-FPM
Restart PHP-FPM services:
/scripts/restartsrv_cpanel_php_fpm
/scripts/restartsrv_apache_php_fpm
PHP-FPM Logs
View the last 100 lines of the PHP-FPM error logs:
tail -100 /usr/local/cpanel/logs/php-fpm/error.log
Common PHP-FPM Errors and Solutions
Error:
[ERROR] Unable to read FPM configuration file
Solution:
- Check the PHP-FPM configuration file for syntax errors:
php-fpm -t
- Correct any errors found in the configuration file:
vi /etc/php-fpm.conf
- Restart PHP-FPM:
/scripts/restartsrv_cpanel_php_fpm
5. Nginx Management
Nginx Status
Check the configuration and status of Nginx:
nginx -t
systemctl status nginx
apachectl -t
Restart Nginx
Restart Nginx with hard restart if needed:
/scripts/restartsrv_nginx --hard
Nginx Logs
View the last 100 lines of the Nginx error logs:
tail -100 /var/log/nginx/error.log
Common Nginx Errors and Solutions
Error:
nginx: [emerg] "server" directive is not allowed here
Solution:
- Validate Nginx configuration:
nginx -t
- Correct the configuration file:
vi /etc/nginx/nginx.conf
- Restart Nginx:
/scripts/restartsrv_nginx --hard
6. ModSecurity Management
ModSecurity Logs
Search for ModSecurity entries in logs:
grep "ModSecurity" /var/log/messages
Common ModSecurity Errors and Solutions
Error:
ModSecurity: Warning. Pattern match "(?i:(?:<\\s*?script|<\\s*?img|<\\s*?iframe))" at ARGS
Solution:
- Review the ModSecurity rule that triggered the warning:
vi /usr/local/apache/conf/modsec2.user.conf
- Modify or disable the specific rule as needed.
7. CloudLinux Management
CloudLinux Status
Check the status of the CloudLinux LVE Manager:
cldetect --version
Check the status of the CloudLinux CageFS:
cagefsctl --status
Check the status of the CloudLinux Database Governor:
service db_governor status
Restart CloudLinux Services
Restart CloudLinux LVE Manager:
service lvestats restart
Restart CloudLinux CageFS:
cagefsctl --force-update
Overall System Status
Check for failed systemd units:
systemctl --failed
View detailed system logs for errors:
journalctl -xe
8. Kernel Management
Kernel Messages
View the last 100 lines of kernel messages:
tail -100 /var/log/dmesg
Out of Memory (OOM) Errors
Identify OOM errors related to HTTP processes:
egrep "oom_reaper|out of memory" /var/log/messages | grep http | tail -25
egrep "out of memory" /var/log/messages | grep http | tail -25
Killed Process Errors
Identify killed process errors related to HTTP:
egrep "Killed process" /var/log/messages | grep http | tail -25
grep "Killed process" /var/log/messages
grep "oom-killer" /var/log/messages
Identifying Common Errors and Solutions
1. Apache Not Starting
Error:
AH00558: httpd: Could not reliably determine the server's fully qualified domain name
Solution:
- Edit the Apache configuration file:
vi /etc/httpd/conf/httpd.conf
- Add the following line:
ServerName localhost
- Restart Apache:
/scripts/restartsrv_httpd
2. MySQL Connection Issues
Error:
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock'
Solution:
- Check if MySQL service is running:
systemctl status mysqld
- Restart MySQL service:
/scripts/restartsrv_mysql
3. PHP-FPM Fails to Start
Error:
[ERROR] Unable to read FPM configuration file
Solution:
- Check the PHP-FPM configuration file for syntax errors:
php-fpm -t
- Correct any errors found in the configuration file:
vi /etc/php-fpm.conf
- Restart PHP-FPM:
/scripts/restartsrv_cpanel_php_fpm
4. Nginx Configuration Errors
Error:
nginx: [emerg] "server" directive is not allowed here
Solution:
- Validate Nginx configuration:
nginx -t
- Correct the configuration file:
vi /etc/nginx/nginx.conf
- Restart Nginx:
/scripts/restartsrv_nginx --hard
5. High Memory Usage (OOM Errors)
Error:
Out of memory: Kill process
Solution:
- Identify the process causing high memory usage:
top
- Adjust Apache MaxRequestWorkers settings
vi /etc/httpd/conf/httpd.conf
Reduce the value of `MaxRequestWorkers`:
MaxRequestWorkers 150
- Restart Apache:
/scripts/restartsrv_httpd
6. SSH Issues
Error:
sshd: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.
Solution:
- Check for another SSH service running:
netstat -tulpn | grep :22
- Kill the conflicting process or change the port:
vi /etc/ssh/sshd_config
Change the port number, then restart SSH:
sudo systemctl restart sshd.service
Conclusion
Regular monitoring and timely debugging are crucial to maintaining a healthy server environment. This guide provides essential commands and checks for cPanel/Linux servers. For more detailed guides and troubleshooting tips, refer to our [knowledge base](https://www.domainindia.com/knowledgebase) or submit a ticket for personalized support at https://www.domainindia.com/support.
