Centos 7 Bond Two Nic Interfaces and Firewalld

In this post, I will show you how to bond two NIC interfaces together on Centos 7 using the bond 5 mode option while using a single static IP. I’m also assuming you have firewalld configured in this tutorial which is why I have included the zone definitions below.

I have chosen the bond 5 mode as it is my favorite. What is bond 5?

Adaptive transmit load balancing: channel bonding that does not require any special switch support. The outgoing traffic is distributed according to the current load (computed relative to the speed) on each slave. Incoming traffic is received by the current slave. If the receiving slave fails, another slave takes over the MAC address of the failed receiving slave.

• Prerequisite: Ethtool support in the base drivers for retrieving the speed of each slave.

As you can see, bond 5 acts as a load balancer between the NIC’s and also as a failover should a NIC fail. Let’s get started.

First, navigate to the /etc/sysconfig/network-scripts/ directory by typing the following command.

cd /etc/sysconfig/network-scripts

Next, let’s create a new interface file called ifcfg-bond0 using your favorite editor.

vim /etc/sysconfig/network-scripts/ifcfg-bond0

Paste the following lines into this new file and save:

DEVICE=bond0 
TYPE=Bond 
NAME=bond0 
BONDING_MASTER=yes 
BOOTPROTO=static 
ONBOOT=yes 
IPADDR=XX.XXX.XX.XXX 
PREFIX=24 
GATEWAY=XX.XXX.XX.XXX 
DNS1=XX.XX.XX.XX 
DNS2=XX.XX.XX.XX 
BONDING_OPTS="mode=5 
miimon=100" 
ZONE=public

Be sure to replace the (X’s) with your ISP information. Also, be sure to use the correct zone in your setup.

Next, let’s update the two interfaces you want to use as the slave for the newly created bond interface above. Let’s open each one again with your favorite editor and make the following changes.

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp7s0
UUID=t87395473-9h3i-9437-10g4-83jd83jdjf7473
DEVICE=enp7s0
ONBOOT=yes
MASTER=bond0
SLAVE=yes
ZONE=public

TYPE=Ethernet
PROXY_METHOD=none
BROWSER_ONLY=no
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=no
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy
NAME=enp10s0
UUID=t87334s-953i-9327-57e4-jf73hdu73yjhdjfy3
DEVICE=enp10s0
ONBOOT=yes
MASTER=bond0
SLAVE=yes
ZONE=public

You should have noticed the following lines in each file.

ONBOOT=yes
MASTER=bond0
SLAVE=yes

Please note that I’m not 100% sure if the zone is needed in the two slave interface files, but I have added it to be 100% sure it works correctly. Feel free to test without the zone definition here if you like, as it is already defined in the bond interface. If you test it without the zone definition here, please let me know how it went.

Reload Firewalld

firewall-cmd --reload

Restart your network.

systemctl restart network

Now let’s check our bond status.

cat /proc/net/bonding/bond0

Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: transmit load balancing
Primary Slave: None
Currently Active Slave: enp10s0
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: enp7s0
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: e0:55:88:e0:32:ee
Slave queue ID: 0

Slave Interface: enp10s0
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: e0:30:88:e0:47:03
Slave queue ID: 0

As you can see, the new bond interface is working and the active interface is enp10s0.