wrong reason:
The cloned Linux system is running on a new machine, and the physical address of the new server NIC has been changed. The file /etc/udev/rules.d/70-persistent-net.rules determines the binding between the network card and the MAC address information. The MAC of the cloned network card has changed, so the system thinks that the network device Does not exist, the network cannot be started normally. The other is that the MAC address in /etc/sysconfig/network-scripts/ifcfg-eth0 is also the old information.
Regarding the file /etc/udev/rules.d/70-persistent-net.rules, the system will automatically monitor changes at startup, and then write to /etc/udev/rules.d/70 by /lib/udev/write_net_rules A new configuration section in -persistent-net.rules, the serial number of the network card is incremented in turn (if the original is eth0, an eth1 will be generated after the first modification, and an eth2 will be generated after modification again...), and its ATTR{address The value of } is the mac address corresponding to the current network card.
Solution:
1. Find /etc/udev/rules.d/70-persistent-net.rules to record the mac address of eth1 and delete the file.
2. Edit the /etc/sysconfig/network-scripts/ifcfg-eth0 configuration file, and delete or modify the previous line about the MAC address in the ifcfg-eth0 configuration file to the MAC in 1.
In addition, the IP of the cloned server is set to a static IP. After the clone is completed, BOOTPROTO may become dhcp, re-modify it to static, and then modify the IP address.
3. Restart the machine, the system will automatically generate a 70-persistent-net.rules file, and everything will return to normal.