> For the complete documentation index, see [llms.txt](https://linux-tutorial-cli.gitbook.io/linux-cli-tutorial/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://linux-tutorial-cli.gitbook.io/linux-cli-tutorial/txt-files/file-systems-cocepts/lpic3-306/sys-class-net-bonding_masters.md).

# -sys-class-net-bonding\_masters

The `/sys/class/net/bonding_masters` file in Linux provides a list of **all the bonding interfaces** (also called bond devices) that are currently configured on the system. It contains the names of the bonding interfaces, such as `bond0`, `bond1`, etc.

This file is particularly useful for administrators or scripts to easily identify the active bonding interfaces on the system.

#### Example of Usage

1. **Check the current bonding interfaces on your system:**

```bash
cat /sys/class/net/bonding_masters
```

#### Example Output:

```
bond0
bond1
```

This output indicates that there are two bonding interfaces, `bond0` and `bond1`, on the system.

#### Explanation:

* The `/sys/class/net/bonding_masters` file contains the names of all the **master bonding interfaces** configured on the system.
* Each bonding interface represents a logical link aggregation device that combines multiple physical network interfaces (called slaves) to increase bandwidth or provide redundancy.

#### How to Create or View Bonding Interfaces:

1. **View details of a bonding interface:**

For example, to check the configuration of `bond0`, you can look at:

```bash
cat /sys/class/net/bond0/bonding/mode
```

This command will show the bonding mode (e.g., `active-backup`, `balance-rr`, etc.) for `bond0`.

2. **Creating a bonding interface:**

If you have not created a bonding interface, you can do so by editing the network configuration files or using the following commands:

```bash
# Example command for creating a bond (bond0)
sudo modprobe bonding
sudo ifconfig bond0 up
```

In the `/etc/network/interfaces` file (Debian/Ubuntu) or `/etc/sysconfig/network-scripts/ifcfg-bond0` (RedHat/CentOS), you can configure the bonding interface and add slave interfaces.

Example (Debian/Ubuntu):

```bash
auto bond0
iface bond0 inet static
    address 192.168.1.100
    netmask 255.255.255.0
    bond-slaves eth0 eth1
    bond-mode 1
```

#### Summary

The `/sys/class/net/bonding_masters` file is a simple and efficient way to view all the bonded interfaces on your system. If you are managing network interfaces and need to ensure that multiple network interfaces are aggregated into a single virtual interface, this file helps you confirm the active bonding interfaces.