# Creating or modifying a bond
<a name="config-conductor-live-config-bond-add"></a>

If you set up more Ethernet interfaces on the Conductor Live node, you can optionally bond two Ethernet interfaces. 

You can bond Ethernet interfaces to suit your networking requirements. For example, you might set up two Ethernet interfaces as an active/redundant pair. 

**Important**  
We recommend that when you set up a bond, you set up both eth0 and eth1 with static IP addresses and with eth0, eth1 and bond0 all on the same subnet.

**Prerequisites**  
Before you begin this process, make sure that you have done the following:
+ [Set up the individual Ethernet interfaces](config-conductor-live-config-ethernet-add.md) that you want to bond together.
+ If HA is currently enabled, disable it now. Conductor Live redundancy (HA or *high availability*) must be disabled before you configure Ethernet interfaces. For instructions, see [Disabling Conductor Live HA (high availability)](conductor-live-config-ha-chg.md).

**Warning**  
Don't use the web interface to create or modify a bond because you will break the configuration.

## Step A: Create bond configuration file
<a name="config-conductor-live-config-ethernet-bond-create"></a>

Create a configuration file for the bond interface and name it after the bond.

**To create the bond configuration file**

1. Create the file with the following command.

   ```
   sudo vim /etc/sysconfig/network-scripts/{{ifcfg-bond0}}
   ```

1. Insert the following settings in the file:
   + ***DEVICE*** – Type **bond0**.
   + ***TYPE*** – Type **Bond**.
   + ***NAME*** – Provide a name for the bond that is unique among your bonded interfaces, such as **bond0**.
   + ***BONDING\_MASTER*** – Type **yes**.
   + ***BOOTPROTO*** – If you are using a static IP address for the bond, type **none**. If you are using DHCP, type **dhcp**.
   + ***ONBOOT*** – Type **yes**.
   + ***NM\_CONTROLLED*** – Type **no**.
   + ***IPADDR*** – When you are using a static IP address, complete with your networking information.
   + ***NETMASK*** – When you are using a static IP address, complete with your networking information.
   + ***GATEWAY*** – When you are using a static IP address, complete with your networking information.
   + ***BONDING\_OPTS*** – Type the bonding mode you are using. 

**Bonding modes**  
The following table describes the bonding modes that are available.


****  

| Bonding mode option | Mode name | Description | 
| --- | --- | --- | 
| mode=0 | Round robin | Transmissions are received and sent sequentially on each bonded interface, beginning with the first one available. | 
| mode=1 | Active backup | Transmissions are received and sent out using the first available bonded interface. The other interface is only used if the active interface fails. | 
| mode=2 | Balanced XOR | Using the exclusive-or (XOR) method, the interface matches up the incoming request's MAC address with the MAC address for one of the bonded interface NICs. When this link is established, transmissions are sent out sequentially, beginning with the first available interface. | 
| mode=3 | Broadcast | All transmissions are sent on all interfaces in the bond. | 
| mode=4 | IEEE 802.3ad dynamic link aggregation | This option creates aggregation groups that share the same speed and duplex settings. This transmits and receives on all interfaces in the active aggregator. Requires a switch that is 802.3ad compliant. | 
| mode=5 | Adaptive transmit load balancing | Outgoing traffic is distributed according to current load on each interface in the bond. Incoming traffic is received by the currently active interface. If the receiving interface fails, another interface takes over the MAC address of the failed interface. | 
| mode=6 | Adaptive load balancing | This option includes transmit and receive load balancing for IPV4 traffic. Receive load balancing is achieved through ARP negotiation. | 

**Example**  

```
DEVICE=bond0
TYPE=Bond
NAME=bond0
BONDING_MASTER=yes
BOOTPROTO=none                              
ONBOOT=yes
NM_CONTROLLED=no
IPADDR=192.168.1.70
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
BONDING_OPTS="mode=5 miimon=100"
```

## Step B: Edit Ethernet interface configuration files
<a name="config-conductor-live-config-ethernet-bond-assign"></a>

Access the configuration files for each of the interfaces that are participating in the bond. Add the following lines.

```
MASTER=bond0
SLAVE=yes
```

For help with creating and updating bonding files through the CLI, see [ Using the CLI](https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-network_bonding_using_the_command_line_interface) in the Red Hat *Networking Guide*.

## Step C: Restart the AWS Elemental service configuration files
<a name="config-conductor-live-config-ethernet-bond-restart"></a>

Restart the AWS Elemental service using the following command.

```
sudo systemctl restart network
```

## Step D: Verify the bond
<a name="config-conductor-live-config-ethernet-bond-verify"></a>

Enter this command to display information about a specific bond:

```
cat /proc/net/bonding/bond0
```

In this example, bond0 is correctly set up.

**Example**  

```
[elemental@host~]$ 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: eth0
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0

Slave Interface: eth0
MII Status: up
Speed: 10000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:50:56:b8:64:44
Slave queue ID: 0

Slave Interface: eth2
MII Status: up
Speed: 10000 Mbps
Duplex: full
Link Failure Count: 0
Permanent HW addr: 00:50:56:8d:8e:db
Slave queue ID: 0
[elemental@host~]$
```