After installing CentOS7, small settings are necessary.
NTP client
Install chrony (an NTP client) by yum.
[root@server ~]# yum -y install chrony Loaded plugins: (snipped...) Installed: chrony.x86_64 0:3.4-1.el7 Dependency Installed: libseccomp.x86_64 0:2.3.1-4.el7 Complete!
Set NTP servers in /etc/chrony.conf
# in /etc/chrony.conf # Use public servers from the pool.ntp.org project. # Please consider joining the pool (http://www.pool.ntp.org/join.html). #server 0.centos.pool.ntp.org iburst #server 1.centos.pool.ntp.org iburst #server 2.centos.pool.ntp.org iburst #server 3.centos.pool.ntp.org iburst server (your NTP server) iburst
Enable and start chrony as service
[root@server ~]# systemctl enable chronyd [root@server ~]# systemctl start chronyd
SELinux
Check the status of SELinux and disable it.
[root@server ~]# getenforce Enforcing [root@server ~]# setenforce 0
Disable SELinux by editing /etc/selinux/config permanently.
# This file controls the state of SELinux on the system. # SELINUX= can take one of these three values: # enforcing - SELinux security policy is enforced. # permissive - SELinux prints warnings instead of enforcing. # disabled - No SELinux policy is loaded. SELINUX=disabled