Resolved In case your Apache died on all your CentOS 7 servers tonight...

[HostaHost]

Yum updates tonight installed:

Updated: libselinux.x86_64 2.5-6.el7
Updated: libselinux-utils.x86_64 2.5-6.el7
Updated: selinux-policy.noarch 3.13.1-102.el7_3.7
Updated: selinux-policy-targeted.noarch 3.13.1-102.el7_3.7
Updated: libselinux-python.x86_64 2.5-6.el7
Updated: libselinux-ruby.x86_64 2.5-6.el7
Updated: httpd.x86_64 2.4.6-45.el7.centos

on our CentOS 7 / Plesk 12 servers. Our servers are running Plesk with apache+nginx, so Apache binds to 7080 and 7081. Well, as soon as those new packages went on, all our servers went down with apache refusing to start. Turns out this is selinux screwing things up once again. The fix:

yum install policycoreutils-python -y
semanage port -a -t http_port_t -p tcp 7080
semanage port -a -t http_port_t -p tcp 7081
systemctl start httpd

Probably good idea if Plesk is updated to issue the relevant semanage commands when selinux is enforcing and you switch to nginx+apache.

 

[HostaHost]

Plesk's php-fpm implementation breaks because of this as well.

 

[IgorG]

We do not officially support CentOS 7.3 yet even for Onyx. And I suppose that CentOS 7.3 will be supported for Plesk 12.5 versions later.
So, if want to use SELinux, I suggest you to use supported OS and perform updates carefully - update SELinux only in scope of Plesk updates.