CentOS 7.x network bonding

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CentOS 7.x network bonding

It is possible to combine to NICs in a single bond interface for redundancy, performance, etc. reasons. To configure bond on top of two physical interfaces use following steps:

1. Identify two identical interfaces for creating bond. These interfaces should have same speed and should be connected to same VLAN(s).
2. Go to /etc/sysconfig/network-scripts/ folder
3. Create 'ifcfg-bond0' with contents similar to:

   DEVICE=bond0
   NAME=bond0
   TYPE=Bond
   ONBOOT=yes
   BOOTPROTO=static
   IPADDR=192.168.122.150
   NETMASK=255.255.255.0
   GATEWAY=192.168.122.1
   BONDING_MASTER=yes
   BONDING_OPTS="miimon=0 updelay=0 downdelay=0 mode=4"

   where mode=4 refers to 802.3ad or LACP. For other types of mode such as balance-rr, active-backup, balance-xor, etc. refer to reference links at the end

   In case of less information on network switch end or while using unmanageable switches, use mode=5 as that seems to be able to detect interfaces going up or down properly.

4. Update interface configuration files to depend on bond using:

   DEVICE=ens0
   ONBOOT=yes
   TYPE=Ethernet
   BOOTPROTO=none
   MASTER=bond0
   SLAVE=yes
   NM_CONTROLLED="no"

   where ens0 is the name of one of the two ethernet interfaces to be added to bond

5. Do the same for second ethernet interface
6. Restart network for settings to take effect:

   systemctl restart network

7. Use following to make sure bond is formed properly:

   cat /proc/net/bonding/bond0

Refer:

• http://www.geekpills.com/operating-system/linux/how-to-setup-and-configure-network-bonding-in-rhelcentos-7
• https://www.linuxtechi.com/configure-nic-bonding-in-centos-7-rhel-7/
• https://www.linuxtechi.com/network-bonding-centos-6-rhel-6/

Troubleshooting steps

• If in cat /proc/net/bonding/bond0 output only one interface is shown and other is not showing up then validate SLAVE=yes and MASTER=bond0 are present in the interface configuration file for the other interface.
• If bond0 itself is not getting created make sure DEVICE=bond0, NAME=bond0 etc. is present in ifcfg-bond0 file

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