it took me awhile to figure out why the wordpress update via admin panel of wordpress does not work at all when I already did all the possible permission settings. I found out that it’s not about the permissions.
So I bumped into this one article online and the procedure to fix this ftp issue on centos is as follows
chown -Rv apache:apache /var/www/wordpress/
find /var/www/wordpress/ -type d -exec chmod 755 {} \;
find /var/www/wordpress/ -type f -exec chmod 644 {} \;
chcon -t httpd_sys_rw_content_t /var/www/wordpress/wp-content -R