Ntp and chronyd

Ntp and chronyd

The disadvantages of synchronizing time immediately, affecting the execution of some scheduled tasks

First, synchronize time immediately

Method 1:

Ntpdate ntp.aliyun.com

Method 2: restart the ntp service

Method 3: restart the chrony service

Check the status of ntp and chrony

[root@textbox] # chronyc sources-v210 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 = ^ * localhost 3 6 17 2 + 62us [+ 661us] + /-88ms [root@textbox ~] # [root | @ textbox ~] # ntpq-p remote refid st t when poll reach delay offset jitter====*localhost 119.28.206.193 3u 41 64 177 0.784 1.195 3656236

3. Ntp is used to set up the server.

# Note the original ntp server The original ntp servers are all centos.org American [root@textbox ~] # sed'/ ^ server/s/ ^ / # /'/ etc/ntp.conf-i# add two aliyun [root@textbox ~] # sed'1a server ntp.aliyun.com iburst' / etc/ntp.conf-I [root@textbox ~] # sed'1a server ntp1.aliyun.com iburst' / etc/ntp.conf-i# restart service [root@textbox ~] # systemctl restart ntpd#ntp is as simple as that You can use port [root@textbox ~] # ntpq-p remote refid st t when poll reach delay offset jitter====+120.25.115.20 10.137.53.7 2 u 4 64 17 42.560-8.795 6.944 "203.107.88 100.107.25.114 2 u 4 64 17 15.542-7.021 6.460" 123 "when the server uses Udp [root@textbox ~] # ss-lutnp | grep ntpudp UNCONN 0 192.168.38.140 ntpd 123 *: * users: (("ntpd", pid=61668,fd=19)) udp UNCONN 0 0127.0.1 ss 123 *: * users: (("ntpd", pid=61668) Fd=18)) udp UNCONN 0 0 *: 123 *: * users: (("ntpd", pid=61668,fd=16)) udp UNCONN 0 0 fe80::69d0:5288:fda9:93ae%ens33:123: * users: (("ntpd", pid=61668) Fd=21)) udp UNCONN 0 0:: 1 users: (("ntpd", pid=61668,fd=20)) udp UNCONN 0 0: 123: * users: (("ntpd", pid=61668) Fd=17) # Test [root@linux5 ~] # ntpdate 192.168.38.140 5 Sep 09:17:25 ntpdate [28423]: adjust time server 192.168.38.140 offset-0.007790 sec

IV. Chrony server configuration

Set more items than ntp

[root@imooc-nginx ~] # sed'/ ^ server/s/ ^ / # /'/ etc/chrony.conf-I [root@imooc-nginx ~] # sed'1a server ntp.aliyun.com iburst' / etc/chrony.conf-I [root@imooc-nginx ~] # sed'1a server 0.cn.pool.ntp.org iburst' / etc/chrony.conf-I [root@imooc-nginx ~] # sed'1a server ntp1.aliyun.com iburst' / etc/chrony.conf- I # even if the current server is not synchronized with the specified ntp completion time Still provide service [root@imooc-nginx ~] # sed'1a local stratum 10' / etc/chrony.conf-i# which servers are allowed to synchronize [root@imooc-nginx ~] # sed'1a allow 192.168.0.0 / etc/chrony.conf-I [root@imooc-nginx ~] # systemctl restart chronyd [root@imooc-nginx ~] # systemctl enable chronyd# View chronyd status [root@imooc-nginx ~] # chronyc sources-v210 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 17 4 + 766us [+ 591us] + /-21ms ^-111.230.189. 17426174 + 98us [+ 98us] + /-49ms ^ * 203.107.6.88 26174-187us [- 361us] + /-16ms# Test [root@textbox] # ntpdate 192.168.38.154 5 Sep 09:33:25 ntpdate [61810]: adjust time server 192.168.38.154 offset-0.010546 sec

5. Two ways to automatically synchronize time

1. Ntpdate ntp.aliyun.com writes scheduled tasks and synchronizes them every hour.

2. All servers chrony are enabled, one of which is a time server, and the server of the other servers points to it.

VI. Setting the time zone

[root@textbox ~] # timedatectl set-timezone Asia/Shanghai