Time and date
All machines in the cluster need to have the same time and date settings, including time zones. Use of the Network Time Protocol (NTP) is recommended. Many cluster services are sensitive to time (For example HBase, Kudu, and ZooKeeper) and troubleshooting is easier if time is consistent across all hosts.
You can enable the NTP daemon by running the following commands on RHEL and CentOS 7 operating systems:
systemctl start ntpd.service systemctl enable ntpd.service