Linux compute nodes and desktop machines running CentOS 7 will be rebooted on Thursday, July 6th for software and security updates. This update does not include RHEL 6 systems. Updates will be applied to machines between 7:00 pm and midnight. In an effort to try to minimize any corrupted files or lost data, please save all your work and log out of any CentOS 7 systems before this time.
If you are uncertain what OS is running on machine, you can type "cat /etc/redhat-release" at the command line to find out.