Problem Description

After a CVM with CentOS 6.x operating system is restarted or executes on the service network restart command, its domain names cannot be resolved. In addition, DNS information in the configuration file /etc/resolv.conf is found to be cleared.

Possible Reasons

In CentOS 6.x operating system, initscripts with versions earlier than 9.03.49-1 has a defect due to different grep versions.

Solution

Upgrade initscripts to the latest version and generate DNS information again.

Directions

1. Log in to the CVM.
2. Execute the following command to check the initscripts version, and verify whether a defect exists because the initscripts version is earlier than 9.03.49-1.

   rpm -q initscripts

   A message similar to the one below is returned:

   initscripts-9.03.40-2.e16.centos.x86_64

   As shown above, the initscripts version of initscripts-9.03.40-2 is earlier than the defective version of initscripts-9.03.49-1. There is a risk of DNS information being cleared.
3. Execute the following command to upgrade initscripts to the latest version and generate DNS information again.

   yum makecache
   yum -y update initscripts
   service network restart

4. Execute the following command after the upgrade is completed to check the version information of initscripts, and verify whether the upgrade is successful.

   rpm -q initscripts

   A message similar to the one below is returned:

   initscripts-9.03.58-1.el6.centos.2.x86_64

   As shown above, the version displayed is different from that before the upgrade and is newer than initscripts-9.03.49-1. This indicates that initscripts has been upgraded successfully.