Trying to get MySQL running under CentOS and SELinux? Try disabling the latter, or doing the following to allow MySQL to startup with access to precious system files:
1) install selinux-policy-targeted-sources from your OS vendor
2) add the following two lines to /etc/selinux/targeted/src/policy/domains/program/mysqld.te:
allow mysqld_t random_device_t:chr_file read;
allow mysqld_t urandom_device_t:chr_file read;
3) cd to /etc/selinux/targeted/src/policy and issue the following command:
Worked for me!