Issue/Introduction

This article describes how to add multiple NICs to a VM instance. It applies to the initial diagnosis and resolution of similar issues in ZStack Cloud.

Environment

• Product: ZCF
• Component: Cloud
• Version: 3.x-5.5.30

Symptoms

When creating a VM instance, you might attach multiple networks to it. In this case, the VM instance console displays multiple NICs but no IP addresses.

Possible causes

Each network corresponds to one NIC on a VM instance. Attaching a network to a VM instance is equivalent to connecting a physical NIC to a server. Therefore, ifconfig displays the eth devices. If no IP address is displayed, the NIC is not configured correctly.

Resolution

Create a configuration file for the new NIC based on the eth0 configuration file. The following example uses CentOS 7.2. Paths and files might differ in other Linux versions:

1. Run the following commands in the console to copy the eth0 configuration file:

  # Replace eth0 with eth1 in the configuration file, and remove its UUID information
  cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth1
  sed -i 's/eth0/eth1/g' /etc/sysconfig/network-scripts/ifcfg-eth1
  sed -i '/UUID*/d' /etc/sysconfig/network-scripts/ifcfg-eth1

2. Restart the network for the configuration to take effect:

  /etc/init.d/network restart

3. Run ifconfig. The newly added NIC now displays an IP address. If multiple networks are attached to the VM instance, repeat the preceding operations for each network.