Interface Bonding on Redhat

This step by step guide is for configuring interface bonding on Redhat based operating systems.

For the following guide we will use the following data and assume that you are running all commands as the root user:

Step-by-step guide

How to do it:

1. Determine whether the bonding module is loaded:

lsmod | grep bonding

2. If it is loaded go to step 3, otherwise:

modprobe bonding

3. With the bonding module loaded into the kernel we need to determine what the interfaces are called:

ls /sys/class/net/

4. From this list we need to select which interfaces we are going to use in the bond (the slaves). In most cases this will be the first two interfaces (eth0 & eth1, em1 & em2, eno0 & eno1 etc.)
   Before we change the physical interface configurations, we need to create the bond interface.
   The simplest way to create the bond interface configuration file is to copy the primary interface file (ifcfg-em1) to the bond interface file (ifcfg-bond0) and edit it.

cp /etc/sysconfig/network-scripts/ifcfg-em1 /etc/sysconfig/network-scripts/ifcfg-bond0 && sed -i 's/em1/bond0/g' /etc/sysconfig/network-scripts/ifcfg-bond0 && sed -i 's/HWADDR/MACADDR/g' /etc/sysconfig/network-scripts/ifcfg-bond0 && sed -i '/uuid/d' /etc/sysconfig/network-scripts/ifcfg-bond0 && echo 'BONDING_OPTS="mode=802.3ad lacp_rate=1"' >> /etc/sysconfig/network-scripts/ifcfg-bond0 && echo 'USERCTL=no' >> /etc/sysconfig/network-scripts/ifcfg-bond0 && echo 'NM_CONTROLLED=no' >> /etc/sysconfig/network-scripts/ifcfg-bond0

This will do the following configuration changes:

DEVICE=em1 
BOOTPROTO=static 
IPADDR=192.0.2.2 
SCOPE="peer 192.0.2.1" 
GATEWAY=192.0.2.1 
NETWORK=192.0.2.1 
HWADDR=00:00:5E:00:53:00 
NETMASK=255.255.255.255 
ONBOOT=yes 
TYPE=Ethernet 
DNS1=217.112.87.147 
DNS2=217.112.88.90 
DNS3=217.112.88.10 
IPV6INIT=yes 
IPV6ADDR=2001:0db8:0000:0800:0192:0000:0002:0002/128 
UUID="6eb9d580-b46e-4d63-adcc-17e5df965054"

DEVICE=bond0 
BOOTPROTO=static 
IPADDR=192.0.2.2 
SCOPE="peer 192.0.2.1" 
GATEWAY=192.0.2.1 
NETWORK=192.0.2.1 
MACADDR=00:00:5E:00:53:00 
NETMASK=255.255.255.255 
ONBOOT=yes 
TYPE=Ethernet 
DNS1=217.112.87.147 
DNS2=217.112.88.90 
DNS3=217.112.88.10 
IPV6INIT=yes 
IPV6ADDR=2001:0db8:0000:0800:0192:0000:0002:0002/128 
BONDING_OPTS="mode=802.3ad lacp_rate=1" 
USERCTL=no 
NM_CONTROLLED=no 

We have:

• Renamed the device from em1 to bond0
• Changed the HWADDR to MACADDR
• Set the bonding mode to LACP and set the lacp rate to “Active/Fast”
• Disabled USERCTL
• Disabled Network Manager via NM_CONTROLLED=no

5. Now our bond is configured, we need to configure our slave devices, these should both be identical except for the device name (and the UUID if we are using them), you should edit the ifcfg-em1 and ifcfg-em2 files to look like this:

DEVICE=em1 
BOOTPROTO=none 
ONBOOT=yes 
SLAVE=yes 
MASTER=bond0 
USERCTL=no 
NM_CONTROLLED=no

DEVICE=em2 
BOOTPROTO=none 
ONBOOT=yes 
SLAVE=yes 
MASTER=bond0
USERCTL=no 
NM_CONTROLLED=no

6. With our interfaces configured we need to restart networking to bring up the bond and start using it:

Redhat/CentOS 6: service network restart Redhat/CentOS 7: systemctl restart network

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