linux設置自動同步伺服器時間

最近遇到一個問題，由於兩台伺服器時間的問題，經常導致用戶登錄由於時間差問題而報錯，再三百度，最後整理了一下修改linux定時同步的操作（本方法適用於有自己時間伺服器，沒有的只限於借鑒）

首先確認，我們的服務是否已經安裝了ntp服務

如果沒有安裝，需要先安裝ntp服務

安裝完ntp之後，編輯ntp.conf  

vi /etc/ntp.conf

可以看到文件中內容

# For more information about this file, see the man pages
# ntp.conf(5), ntp_acc(5), ntp_auth(5), ntp_clock(5), ntp_misc(5), ntp_mon(5).

driftfile /var/lib/ntp/drift

# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery

# Permit all access over the loopback interface.  This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1

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

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 127.0.0.1
#server 1.centos.pool.ntp.org
#server 2.centos.pool.ntp.org

#broadcast 192.168.1.255 autokey        # broadcast server
#broadcastclient                        # broadcast client
#broadcast 224.0.1.1 autokey            # multicast server
#multicastclient 224.0.1.1              # multicast client
#manycastserver 239.255.254.254         # manycast server
#manycastclient 239.255.254.254 autokey # manycast client

# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available.
# local clock
#fudge  127.127.1.0 stratum 10

# Enable public key cryptography.
#crypto

includefile /etc/ntp/crypto/pw

# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography.
keys /etc/ntp/keys

　　在文件中 可以看到修改標出來的ip地址，改為自己的時間伺服器地址，也可以是功能變數名稱

修改後保存退出

命令行輸入

crontab -e

　　設置定時任務，其這裡設置的是

* * */1 * * /usr/sbin/ntpdate 127.0.0.1 >> /home/logs/ntpd.log

　同樣修改ip地址 
然後創建日誌文件夾用來存放日誌

mkdir /home/logs

　　ok 大功告成，過幾分鐘在日誌文件夾可以看到日誌文件，瀏覽會發現，時間差不超過0.01s .一般來說是夠用了的