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集群内部配置chrony时间同步

下面操作在CentOS7上进行，ubuntu的话类似，安装方式和配置文件位置稍有区别

方法一：全部互联网同步时间

所有机器执行下面操作。

ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
yum install chrony -y
sed '/^server/s/^/#/' /etc/chrony.conf -i
sed '1a server ntp.aliyun.com iburst' /etc/chrony.conf -i
sed '1a server 0.cn.pool.ntp.org iburst' /etc/chrony.conf -i
sed '1a server ntp1.aliyun.com iburst' /etc/chrony.conf -i
systemctl restart chronyd
systemctl enable chronyd

方法二：从其中一台机器同步

比如有下面5台服务器，k8s-master节点做时间同步源，其他节点都从此节点同步。

k8s-master服务器做时间同步源的配置

ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
yum install chrony -y
sed '/^server/s/^/#/' /etc/chrony.conf -i      #删除其他的时间源
sed '1a server ntp.aliyun.com iburst' /etc/chrony.conf -i
sed '1a server 0.cn.pool.ntp.org iburst' /etc/chrony.conf -i
sed '1a server ntp1.aliyun.com iburst' /etc/chrony.conf -i
sed '1a allow 192.168.0.0/16' /etc/chrony.conf   -i    #添加允许同步的客户端网段
sed '1a local stratum 10' /etc/chrony.conf   -i     #离线也能作为源服务器
systemctl restart chronyd
systemctl enable chronyd

其他节点配置

ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
yum install chrony -y
sed '/^server/s/^/#/' /etc/chrony.conf -i      #删除其他的时间源
sed '1a 192.168.200.128 iburst' /etc/chrony.conf -i
systemctl restart chronyd
systemctl enable chronyd

杂项，验证配置

k8s-master1作为chrony server，检查时间源信息

[root@k8s-master1 ~]# chronyc sources -v
210 Number of sources = 3

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| /   '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,
||      Log2(Polling interval) --.      |          |  yyyy = measured offset,
||                                \     |          |  zzzz = estimated error.
||                                 |    |           \
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^* 120.25.115.20                 2   6    37     1    -23us[ -242us] +/-   23ms
^- ntp8.flashdance.cx            2   6    33    62    -54ms[  -54ms] +/-  178ms
^- 203.107.6.88                  2   6    17    65   -469us[ -688us] +/-   15ms

k8s-master1检查时间源同步状态

[root@k8s-master1 ~]# chronyc sourcestats -v
210 Number of sources = 3
                             .- Number of sample points in measurement set.
                            /    .- Number of residual runs with same sign.
                           |    /    .- Length of measurement set (time).
                           |   |    /      .- Est. clock freq error (ppm).
                           |   |   |      /           .- Est. error in freq.
                           |   |   |     |           /         .- Est. offset.
                           |   |   |     |          |          |   On the -.
                           |   |   |     |          |          |   samples. \
                           |   |   |     |          |          |             |
Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
==============================================================================
120.25.115.20               6   4   136     -0.835     17.041  -6874ns   264us
ntp8.flashdance.cx          6   4   139    +14.016    200.195    -47ms  3579us
203.107.6.88                6   3   136    -12.237    107.962  -1856us   453us

客户端检查时间源信息

[root@k8s-master2 ~]# chronyc sources -v
210 Number of sources = 1

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| /   '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,
||      Log2(Polling interval) --.      |          |  yyyy = measured offset,
||                                \     |          |  zzzz = estimated error.
||                                 |    |           \
MS Name/IP address         Stratum Poll Reach LastRx Last sample               
===============================================================================
^* 192.168.200.128               3   6    17     8    -78us[ -207us] +/-   16ms

验证时间同步完成

同步完成后会显示 NTP synchronized: yes

[root@k8s-master2 ~]# timedatectl 
      Local time: Tue 2019-12-17 13:43:53 CST
  Universal time: Tue 2019-12-17 05:43:53 UTC
        RTC time: Tue 2019-12-17 05:43:53
       Time zone: Asia/Shanghai (CST, +0800)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: n/a