timedatectl set-timezone Asia/Seoul
# 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 kr.pool.ntp.org iburst
server time.bora.net iburst
server time.kornet.net iburst
systemctl restart chronyd
systemctl enable chronyd