:What do I do if the IP address of a Linux ECS instance cannot be renewed when the network process for IP address renewal is abnormal or does not exist?

Problem description

If Dynamic Host Configuration Protocol (DHCP) is configured on a Linux ECS instance and the network process for IP address renewal, such as dhclient, is not started or does not exist, the IP address of the instance cannot be renewed when the IP lease expires. The issue interrupts network connections. To restore network connections, you must resolve the issue and make sure that the network configurations are correct.

Solution

Step 1: Check the status of the network process

Run the ps -ef |grep [$Network process] command to check whether the network process exists. If the network process does not exist, potential risks exist. The following table describes the network processes that correspond to different operating system (OS) distributions for IP address renewal when DHCP is configured.

/sbin/dhclient

/usr/sbin/NetworkManager

/lib/systemd/systemd-networkd

/usr/lib/wicked/bin/wickedd-dhcp4 

Step 2: Restart the network service associated with the network process

Restart the network service associated with the network process to handle service exceptions or resolve the issue that the network process does not exist. The network service name varies based on the Linux distribution and version. The following table describes the network service names that correspond to different Linux distributions and versions and the commands that can be used to start the network services.

service network restart

systemctl restart network

systemctl restart NetworkManager

systemctl restart networking

systemctl restart networking

systemctl restart networking

service networking restart

systemctl restart networking

systemctl restart systemd-networkd

systemctl restart systemd-networkd

systemctl restart wicked

systemctl restart wicked

systemctl restart wicked

systemctl restart systemd-networkd