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웹서버 selinux 관련 설정
setsebool -P httpd_can_network_connect 1
setsebool -P httpd_can_network_connect_db 1
setsebool -P httpd_can_network_relay 1
chcon -R -t httpd_sys_rw_content_t /var/www/html/   ===> 웹서버 읽기/쓰기 권한
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Main connection [MySQLi]: Permission denied 에러 발생시
# semanage fcontext -a -t mysqld_var_run_t /var/lib/mysql/mysql.sock
# restorecon -Rv /var/lib/mysql/mysql.sock
# chcon -t mysqld_exec_t /usr/sbin/mariadbd
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