Alibaba Cloud intranet and public NTP server (Network Time Protocol - Time Synchronization Service)

Keywords: Alibaba Cloud intranet and public NTP server (Network Time Protocol - Time Synchronization Service)
1. Introduction:
NTP is the Network Time Protocol, which is a protocol used to synchronize the time of each computer in the network.
In the world of computers, time is very important. For example, for scientific research activities such as rocket launch, the requirements for the unity and accuracy of time are very high. Whether it is according to the time of computer A or the time of computer B time? NTP is used to solve this problem. NTP (Network Time Protocol, Network Time Protocol) is a protocol used to synchronize the time of each computer in the network. Its purpose is to synchronize the computer's clock to UTC, and its accuracy can reach 0.1ms in the local area network, and its accuracy can reach 1-50ms in most places on the Internet.
It can make the computer time synchronization with its server or clock source (such as quartz clock, GPS, etc.), it can provide high-precision time correction, and can use encrypted confirmation to prevent virus protocol attacks.


2. Alibaba Cloud intranet and public NTP server

Update   time: 2016-07-12 15:23:55 Share:
Intranet NTP server

Alibaba Cloud provides an internal NTP time server for ECS, as follows:

    10.143.33.50
    10.143. 33.51
    10.143.33.49
    10.143.0.44
    10.143.0.45
    10.143.0.46

public NTP server

Although non-Alibaba Cloud devices cannot use Alibaba Cloud's intranet NTP server, Alibaba Cloud provides a public NTP server for devices on the Internet. Its main features are GPS, Beidou timing, atomic clock punctuality, multi-machine room and multi-link redundancy.

The service domain name is:

    Unix system: time1-7.aliyun.com
    Windows: time.pool.aliyun.com

In addition, Aliyun also provides other basic Internet services, such as:

    public DNS: 223.5.5.5/223.6.6.6, The domain name is http://www.alidns.com
    public mirror station: http://mirrors.aliyun.com/ The mirror synchronization frequency is 2:00-4:00 am every day, covering most open source software and Linux distributions.

3. Domestic public NTP services - most of them are available
ntp.sjtu.edu.cn 202.120.2.101 (Shanghai Jiaotong University Network Center NTP server address)
s1a.time.edu.cn Beijing University of Posts and Telecommunications
s1b.time.edu.cn Tsinghua University
s1c .time.edu.cn Peking University
s1d.time.edu.cn Southeast University
s1e.time.edu.cn Tsinghua University
s2a.time.edu.cn Tsinghua University
s2b.time.edu.cn Tsinghua University
s2c.time.edu. cn Beijing University of Posts and Telecommunications
s2d.time.edu.cn Southwest Network Center
s2e.time.edu.cn Northwest Network Center
s2f.time.edu.cn Northeast Network Center
s2g.time.edu.cn Southeast China Network Center
s2h.time.edu.cn Sichuan University Network Management Center
s2j.time. edu.cn Dalian University of Technology Network Center
s2k.time.edu.cn CERNET Guilin master node
s2m.time.edu.cn Peking University


IV . Use Network Time Protocol (NTP) server

1. If there is a time server in the company network: 10.85.10.80, you only need to modify the NTP service configuration file on each node to synchronize each node with the time server. Can.

# vi /etc/ntp.conf

Server 10.85.10.80 prefer

Driftfile /var/lib/ntp/drift

Broadcastdelay 0.008

After modification, restart the ntp service

#/etc/init.d/ntpd restart

2. If there is no time service, then One of the 2 nodes of RAC can be used as a server. Another sync with this server will do.

Join node1 as the server, its IP is: 10.85.10.119, modify the configuration file #vi

/etc/ntp.conf

Server 127.127.1.0 -- local clock

Fudge 127.127.1.0 stratum 11

Broadcastdelay 0.008

Node2 syncs with node1.


Modify the ntp configuration file of node2

# vi /etc/ntp.conf

Server 10.85.10.119 prefer

Driftfile /var/lib/ntp/drift

Broadcastdelay 0.008

After modification, restart the ntp service

#/etc/init.d/ntpd restart


or in node2 is using crontab to synchronize time with the server

*/15 * * * * ntpdate 10.85.10.119