# ubuntu 时间同步
# chrony
- 安装
apt-get install chrony
- 配置
$vi /etc/chrony/chrony.conf
# Welcome to the chrony configuration file. See chrony.conf(5) for more
# information about usuable directives.
# This will use (up to):
# - 4 sources from ntp.ubuntu.com which some are ipv6 enabled
# - 2 sources from 2.ubuntu.pool.ntp.org which is ipv6 enabled as well
# - 1 source from [01].ubuntu.pool.ntp.org each (ipv4 only atm)
# This means by default, up to 6 dual-stack and up to 2 additional IPv4-only
# sources will be used.
# At the same time it retains some protection against one of the entries being
# down (compare to just using one of the lines). See (LP: #1754358) for the
# discussion.
#
# About using servers from the NTP Pool Project in general see (LP: #104525).
# Approved by Ubuntu Technical Board on 2011-02-08.
# See http://www.pool.ntp.org/join.html for more information.
pool ntp.ubuntu.com iburst maxsources 4
pool 0.ubuntu.pool.ntp.org iburst maxsources 1
pool 1.ubuntu.pool.ntp.org iburst maxsources 1
pool 2.ubuntu.pool.ntp.org iburst maxsources 2
# This directive specify the location of the file containing ID/key pairs for
# NTP authentication.
keyfile /etc/chrony/chrony.keys
# This directive specify the file into which chronyd will store the rate
# information.
driftfile /var/lib/chrony/chrony.drift
# Uncomment the following line to turn logging on.
#log tracking measurements statistics
# Log files location.
logdir /var/log/chrony
# Stop bad estimates upsetting machine clock.
maxupdateskew 100.0
# This directive enables kernel synchronisation (every 11 minutes) of the
# real-time clock. Note that it can’t be used along with the 'rtcfile' directive.
rtcsync
# Step the system clock instead of slewing it if the adjustment is larger than
# one second, but only in the first three clock updates.
makestep 1 3
- 允许chronyd服务自动启动并启动chronyd服务：
systemctl enable chronyd
systemctl start chronyd
systemctl status chronyd
- 查看同步状态
#查看 ntp_servers 状态
chronyc sources -v
#查看 ntp_sync 状态
chronyc sourcestats -v
#查看 ntp_servers 是否在线
chronyc activity -v
#查看 ntp 详细信息
chronyc tracking -v
# ntp
- 安装
apt-get install -y ntp
- 配置
#vi /etc/ntp.conf
# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help
driftfile /var/lib/ntp/ntp.drift
# Enable this if you want statistics to be logged.
statsdir /var/log/ntpstats/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
# Specify one or more NTP servers.
# Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board
# on 2011-02-08 (LP: #104525). See http://www.pool.ntp.org/join.html for
# more information.
pool cn.pool.ntp.org iburst
pool 0.ubuntu.pool.ntp.org iburst
pool 1.ubuntu.pool.ntp.org iburst
pool 2.ubuntu.pool.ntp.org iburst
pool 3.ubuntu.pool.ntp.org iburst
# Use Ubuntu's ntp server as a fallback.
pool ntp.ubuntu.com
# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details. The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.
# By default, exchange time with everybody, but don't allow configuration.
restrict -4 default kod notrap nomodify nopeer noquery limited
restrict -6 default kod notrap nomodify nopeer noquery limited
# Local users may interrogate the ntp server more closely.
restrict 127.0.0.1
restrict ::1
# Needed for adding pool entries
restrict source notrap nomodify noquery
# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict 192.168.123.0 mask 255.255.255.0 notrust
# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 192.168.123.255
# If you want to listen to time broadcasts on your local subnet, de-comment the
# next lines. Please do this only if you trust everybody on the network!
#disable auth
#broadcastclient
#Changes recquired to use pps synchonisation as explained in documentation:
#http://www.ntp.org/ntpfaq/NTP-s-config-adv.htm#AEN3918
#server 127.127.8.1 mode 135 prefer # Meinberg GPS167 with PPS
#fudge 127.127.8.1 time1 0.0042 # relative to PPS for my hardware
#server 127.127.22.1 # ATOM(PPS)
#fudge 127.127.22.1 flag3 1 # enable PPS API
- 启动服务
systemctl enable ntpd
systemctl start ntpd
- 查看同步状态
# ntpstat
# 结果如下:
synchronised to NTP server (203.107.6.88) at stratum 3
time correct to within 54 ms
polling server every 64 s
# 简单配置-ntpdate
# 安装 ntpdate
apt-get install ntpdate
# 设置系统时间与网络时间同步（cn.pool.ntp.org 位于中国的公共 NTP 服务器）
ntpdate cn.pool.ntp.org
# 将系统时间写入硬件时间
hwclock --systohc
# rdate从ntp服务器同步时间
除了ntpdate可以同步两台主机之间的时间以外，另外一个工具就是rdate
查看时间服务器的时间:
rdate time-b.nist.gov
设置时间和时间服务器同步:
rdate -s time-b.nist.gov
man rdate # 查看rdate帮助
国内常用NTP服务器地址及IP：
s1d.time.edu.cn 东南大学
s1e.time.edu.cn 清华大学
s2a.time.edu.cn 清华大学
s2b.time.edu.cn 清华大学
s2c.time.edu.cn 北京邮电大学
ntp.sjtu.edu.cn 202.120.2.101 (上海交通大学网络中心NTP服务器地址）
s1a.time.edu.cn 北京邮电大学
s1b.time.edu.cn 清华大学
s1c.time.edu.cn 北京大学
clock.cuhk.edu.hk 香港中文大学授时中心