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How to Configure NTP Server for Oracle RAC Installation


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How to Configure NTP Server Locally Without Internet Access

I wrote this post just to full fill the requirement of having NTP server for oracle RAC installation on your laptop. If you are installing RAC in your company NTP server already configured for time synchronization can be used. 
Step1: Install Packages for NTP
Mount your CD and Install following RPM if already not installed
#rpm -ivh ntp-4.2.6p5-25.0.1.el7.x86_64.rpm
#rpm -ivh ntpdate-4.2.6p5-25.0.1.el7.x86_64.rpm
Step2: Configure  /etc/ntp.conf
Edit /etc/ntp.conf file and locate the below entry and uncomment it. Also modify IP address and mask according to your network
restrict 192.9.1.0 mask 255.255.255.0 nomodify notrap
Step3: Comment out the default ntp servers listed in /etc/ntp.conf. In my case it is
#server 0.rhel.pool.ntp.org iburst
#server 1.rhel.pool.ntp.org iburst
#server 2.rhel.pool.ntp.org iburst
#server 3.rhel.pool.ntp.org iburst
Step4:  Locate below entry and comment out if it is there in /etc/ntp.conf
#restrict ::1
Step5: dd the entry of your ntp server in /etc/ntp.conf
server dns.oracle.com prefer
Note : Do not forget to add additional these 2 Entries. These are required to access its own system clock, also called the local clock.
server 127.127.1.0
fudge 127.127.1.0 stratum 10
Step6: Disable iptables

#service iptables stop
#service ip6tables stop
#chkconfig  iptables off
#chkconfig ip6tables off
Step7:  Start ntp Service
#systemctl start  ntpd.service
#systemctl enable ntpd.service
#ntpq -p
Note:- You are now done with NTP server configuration. Now just configure the NTP client (oracle DB server ) to use this NTP server to synchronize the time. 

Step by Step How to Configure NTP Client.

Step1: Mount your CD and Install following RPM if already not installed
#rpm -ivh ntp-4.2.6p5-25.0.1.el7.x86_64.rpm
#rpm -ivh ntpdate-4.2.6p5-25.0.1.el7.x86_64.rpm
Step2: Edit /etc/ntp.conf and add below entry
server 192.9.1.102 <==this is your NTP Server
Step3: Start ntp Service on your client too
#systemctl start  ntpd.service
#systemctl enable ntpd.service
step4: Synchronize your local time with the server
# ntpdate -u 192.9.1.102
15 Jun 11:12:17 ntpdate[5225]: adjust time server 192.9.1.102 offset 0.000615 sec
#ntpq -p


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