Configure Linux Cluster time synchronization (ntp)

Keywords: CentOS Hadoop RPM network

Environmental Science:
Now there are three virtual machines of CentOS 7, namely, Hadoop 102, Hadoop 103 and Hadoop 104. Now configure ntp service (central server) on Hadoop 102. Hadoop 103 and 104 pull the time on Hadoop 102 respectively

1. Check whether ntp is installed (check and install all 3 sets, and make sure they are not running. If they are already running, stop them)

Switch to root
If ntp is not installed, install it all at once

[root@hadoop104 ~]# rpm -qa|grep ntp
[root@hadoop104 ~]# 
[root@hadoop104 ~]# 
[root@hadoop104 ~]# 
[root@hadoop104 ~]# 
[root@hadoop104 ~]# yum -y install ntp
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.lzu.edu.cn
 * extras: ap.stykers.moe
 * updates: ap.stykers.moe
base                                                                        | 3.6 kB  00:00:00     
extras                                                                      | 2.9 kB  00:00:00     
updates                                                                     | 2.9 kB  00:00:00     
Resolving Dependencies
--> Running transaction check
---> Package ntp.x86_64 0:4.2.6p5-29.el7.centos will be installed
--> Processing Dependency: ntpdate = 4.2.6p5-29.el7.centos for package: ntp-4.2.6p5-29.el7.centos.x86_64
--> Processing Dependency: libopts.so.25()(64bit) for package: ntp-4.2.6p5-29.el7.centos.x86_64
--> Running transaction check
---> Package autogen-libopts.x86_64 0:5.18-5.el7 will be installed
---> Package ntpdate.x86_64 0:4.2.6p5-29.el7.centos will be installed
--> Finished Dependency Resolution

Dependencies Resolved

===================================================================================================
 Package                   Arch             Version                           Repository      Size
===================================================================================================
Installing:
 ntp                       x86_64           4.2.6p5-29.el7.centos             base           548 k
Installing for dependencies:
 autogen-libopts           x86_64           5.18-5.el7                        base            66 k
 ntpdate                   x86_64           4.2.6p5-29.el7.centos             base            86 k

Transaction Summary
===================================================================================================
Install  1 Package (+2 Dependent packages)

Total download size: 701 k
Installed size: 1.6 M
Downloading packages:
(1/3): autogen-libopts-5.18-5.el7.x86_64.rpm                                |  66 kB  00:00:00     
(2/3): ntp-4.2.6p5-29.el7.centos.x86_64.rpm                                 | 548 kB  00:00:00     
(3/3): ntpdate-4.2.6p5-29.el7.centos.x86_64.rpm                             |  86 kB  00:00:00     
---------------------------------------------------------------------------------------------------
Total                                                              1.6 MB/s | 701 kB  00:00:00     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : autogen-libopts-5.18-5.el7.x86_64                                               1/3 
  Installing : ntpdate-4.2.6p5-29.el7.centos.x86_64                                            2/3 
  Installing : ntp-4.2.6p5-29.el7.centos.x86_64                                                3/3 
  Verifying  : ntp-4.2.6p5-29.el7.centos.x86_64                                                1/3 
  Verifying  : ntpdate-4.2.6p5-29.el7.centos.x86_64                                            2/3 
  Verifying  : autogen-libopts-5.18-5.el7.x86_64                                               3/3 

Installed:
  ntp.x86_64 0:4.2.6p5-29.el7.centos                                                               

Dependency Installed:
  autogen-libopts.x86_64 0:5.18-5.el7            ntpdate.x86_64 0:4.2.6p5-29.el7.centos           

Complete!
[root@hadoop104 ~]# 

It's OK to have the following

[root@hadoop104 ~]# 
[root@hadoop104 ~]# 
[root@hadoop104 ~]# rpm -qa|grep ntp  
ntp-4.2.6p5-29.el7.centos.x86_64
ntpdate-4.2.6p5-29.el7.centos.x86_64
[root@hadoop104 ~]# 
[root@hadoop104 ~]# 

2. Configure Hadoop 102

[root@hadoop103 ~]# vi /etc/ntp.conf 

The amendment is as follows:

1. Remove the following comments and change to your own segment

# Hosts on local network are less restricted.
restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

2. Comment out the time taken from the public network

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.centos.pool.ntp.org iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst

3. When the node loses the network connection, the local time can still be used as the time server to provide time synchronization for other nodes in the cluster
Find a place to add:

server 127.127.1.0
fudge 127.127.1.0 stratum 10

4. Configure vi /etc/sysconfig/ntpd

[root@hadoop102 hadoop-2.7.7]# 
[root@hadoop102 hadoop-2.7.7]# vi /etc/sysconfig/ntpd
[root@hadoop102 hadoop-2.7.7]# 

Add a line:

SYNC_HWCLOCK=yes

5. Restart the ntpd service

[root@hadoop102 hadoop-2.7.7]# 
[root@hadoop102 hadoop-2.7.7]# systemctl start ntpd  
[root@hadoop102 hadoop-2.7.7]# 
[root@hadoop102 hadoop-2.7.7]# systemctl enable ntpd 

To see if it started successfully:

[root@hadoop102 hadoop-2.7.7]# 
[root@hadoop102 hadoop-2.7.7]# systemctl status ntpd       
● ntpd.service - Network Time Service
   Loaded: loaded (/usr/lib/systemd/system/ntpd.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2020-01-29 23:02:59 EST; 1min 22s ago
 Main PID: 17717 (ntpd)
   CGroup: /system.slice/ntpd.service
           └─17717 /usr/sbin/ntpd -u ntp:ntp -g

Jan 29 23:02:59 hadoop102 ntpd[17717]: Listen and drop on 1 v6wildcard :: UDP 123
Jan 29 23:02:59 hadoop102 ntpd[17717]: Listen normally on 2 lo 127.0.0.1 UDP 123
Jan 29 23:02:59 hadoop102 ntpd[17717]: Listen normally on 3 ens33 192.168.1.102 ...23
Jan 29 23:02:59 hadoop102 ntpd[17717]: Listen normally on 4 lo ::1 UDP 123
Jan 29 23:02:59 hadoop102 ntpd[17717]: Listen normally on 5 ens33 fe80::e804:aa7...23
Jan 29 23:02:59 hadoop102 ntpd[17717]: Listening on routing socket on fd #22 for...es
Jan 29 23:02:59 hadoop102 ntpd[17717]: 0.0.0.0 c016 06 restart
Jan 29 23:02:59 hadoop102 ntpd[17717]: 0.0.0.0 c012 02 freq_set kernel 0.000 PPM
Jan 29 23:02:59 hadoop102 ntpd[17717]: 0.0.0.0 c011 01 freq_not_set
Jan 29 23:03:00 hadoop102 ntpd[17717]: 0.0.0.0 c514 04 freq_mode
Hint: Some lines were ellipsized, use -l to show in full.
[root@hadoop102 hadoop-2.7.7]# 
[root@hadoop102 hadoop-2.7.7]# 

Configuration of other machines (required by Hadoop 103 and 104) (root user is required)

Configure the timing task to synchronize with the time server once

[root@hadoop103 ~]# crontab -e

Add the following (synchronize every 10 minutes):

*/10 * * * * /usr/sbin/ntpdate hadoop102                                         

After saving, the following contents are displayed, indicating success:

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Posted by shaoen01 on Thu, 30 Jan 2020 08:16:00 -0800