Linux Interface Bonding

We bond two or more network interface together so that if one interface is down, we will have the other interface as backup.

We will set up this on Centos 6 Minimal installation.

1. Load required module

   modprobe --first-time bonding

2. Verify module loaded

   modinfo bonding 3. Create a bond interface script

   vi /etc/sysconfig/network-scripts/ifcfg-bond0 4. Put below code as its content

   DEVICE=bond0 IPADDR=[IP address] NETMASK=255.255.255.0 ONBOOT=yes BOOTPROTO=none USERCTL=no NM_CONTROLLED=no BONDING_OPTS="mode=1 miimon=100 fail_over_mac=1"

3. Edit eth1 and eth2 script

   eth1 vi /etc/sysconfig/network-scripts/ifcfg-eth1 DEVICE=eth1 HWADDR=ff:ff:ff:ff:ff:ff TYPE=Ethernet ONBOOT=yes NM_CONTROLLED=no BOOTPROTO=none MASTER=bond0 SLAVE=yes USERCTL=no eth2 vi /etc/sysconfig/network-scripts/ifcfg-eth2 DEVICE=eth2 HWADDR=ff:ff:ff:ff:ff:ff TYPE=Ethernet ONBOOT=yes NM_CONTROLLED=no BOOTPROTO=none MASTER=bond0 SLAVE=yes USERCTL=no 1. Set bond0 as autostart. This configuration will survive reboot

   vi /etc/modprobe.d/bonding.conf alias bond0 bonding

4. Save both script and restart network

   service network restart

5. Verify bond interface working

   ``` cat /proc/net/bonding/bond0 Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

   Bonding Mode: load balancing (round-robin) MII Status: up MII Polling Interval (ms): 0 Up Delay (ms): 0 Down Delay (ms): 0

   Slave Interface: eth1 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: [MAC ADDRESS] Slave queue ID: 0

   Slave Interface: eth2 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: [MAC ADDRESS] Slave queue ID: 0 ```

Reference

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/s2-networkscripts-interfaces-chan.html

https://community.oracle.com/thread/2546040

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.3/html/Installation_Guide/Bonding_Modes.html