Network Configuration

Kubernetes cluster network configuration. Single-node Converged Architecture can skip this step. This configuration only applies to multi-node Converged Architecture and Professional Architecture cluster installations. All cluster machines must have consistent network settings.

Purpose and Requirements

Network Interface Name Consistency Requirement

In a Kubernetes cluster, to ensure proper operation of inter-node communication, Pod network communication (CNI), and core components like kubelet, all nodes must use the same network interface name (NIC name) for internal cluster communication.

• Issue Source: Different servers or virtualization environments may generate different default NIC names (e.g., eth0, ens160, eno1, etc.).
• Requirement: To avoid communication anomalies, all node communication NIC names must be unified, recommended to be eth0.

Check Current NIC Names

On each node server, run the following command to confirm the NIC name used for cluster communication:

ip addr show

Or use a more concise command to get the name list:

ip -o link show | awk -F': ' '{print $2}'

Identify the actual name of the NIC you plan to use for cluster communication.

Modify NIC Names

If communication NIC names are inconsistent across nodes, you can use netplan's set-name feature to rename and unify them to the target name (e.g., eth0).

Identify Current NIC Information

Run the command to view detailed information and record the current NIC name and MAC address:

ip link show

Example output and information recording:

2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 3c:ec:ef:a1:93:0f brd ff:ff:ff:ff:ff:ff

Current Information Recorded: NIC name is eno1, MAC address is 3c:ec:ef:a1:93:0f.

Edit Netplan Configuration File

The configuration file is usually a .yaml file under /etc/netplan/ (e.g., 00-installer-config.yaml):

vim /etc/netplan/00-installer-config.yaml

Add or modify configuration content, set IP, gateway, DNS, and use set-name and match.macaddress for renaming:

# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}

network:
  ethernets:
    eno1: # Replace with current NIC name
      addresses:
        - 192.168.100.148/24 # Replace with your IP address and subnet mask
      routes:
        - to: default
          via: 192.168.100.1
      nameservers:
        addresses:
          - 192.168.100.1 # Replace with your DNS server address
      # Target name: rename eno1 to eth0
      set-name: eth0
      match:
        # Exact match MAC address
        macaddress: 3c:ec:ef:a1:93:0f # Replace with your recorded MAC address
  version: 2

Apply Configuration and Activate

Run the netplan apply command to activate the new network configuration and NIC renaming:

netplan apply

Important Note: If you are operating remotely via SSH, SSH connection may be temporarily interrupted after applying this configuration. Ensure you have serial console, IPMI, or other out-of-band management methods for backup access in case network renaming fails and connection is lost.

Open the configuration file 99-disable-network-config.cfg, this file comes from the comment section in the configuration above:

vim /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg

Add the following content:

network: {config: disabled}

Verify Renaming

Run the following command to verify the NIC has been successfully renamed to the target name eth0:

ip addr show eth0

Ensure the NIC name has been successfully changed from the original name (e.g., eno1) to eth0, and the network connection is normal.