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udpcon
Asked: 2019-06-07 07:20:37 +0800 CST

Bonding stops working when disconnecting primary interface Ubuntu 18.04

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I have tried to set up bonding between two switches that link to one switch that is linked to a camera (10.0.10.10):

Camera
  |
  |
Switch 1 - - - - - - - - 
  |                    |
  | A                  | B
  |                    |
Switch Primary      Switch Secondary
  |                    |
C | enp3s4f0         D | enp3s4f1 
  |                    |
  |                    |
 ---------------------------
 |Ubuntu 18.04             |
 |       bond0             |
 |------------------------ |

The goal is to be able to ping the camera if any of connections A/B/C/D die. Currently, if connection A dies, the camera cannot be pinged. If any other connection fails, it can still ping the camera.

This is my 01-netcfg.yaml

network:
  version: 2
  renderer: networkd
  ethernets:
    enp3s4f0:
      addresses: [ ]
    enp3s4f1:
      addresses: [ ]
    bonds:
      bond0:
        addresses: [ 10.0.10.101/24 ]
        gateway4: 10.0.10.10
        nameservers:
          addresses: [ 1.1.1.1, 1.1.1.0 ]
        interfaces: [ enp3s4f0, enp3s4f1 ]
        parameters:
          mode: active-backup
          primary: enp3s4f0

After applying the netplan, no errors are thrown:

sudo netplan apply

The problem is that when A is disconnected, the server still recognizes connection C as active so the bond does not change its interface and therefore it keeps trying to reach the camera from Primary Switch, which isn’t possible.

networking 18.04 netplan network-bonding

1 Answers

  1. Best Answer

    From the netplan.io reference page here we find bond parameters that will help us:

    arp-interval (scalar)
    Set the interval value for how frequently ARP link monitoring should 
    happen. The default value is 0, which disables ARP monitoring. For the
    networkd backend, this maps to the ARPIntervalSec= property. If no time
    suffix is specified, the value will be interpreted as milliseconds.

arp-ip-targets (sequence of scalars) IPs of other hosts on the link which
    should be sent ARP requests in order to validate that a slave is up. 
    This option is only used when arp-interval is set to a value other than 0.
    At least one IP address must be given for ARP link monitoring to function.
    Only IPv4 addresses are supported. You can specify up to 16 IP addresses.
    The default value is an empty list.

    So, in the bond0 stanza, we changed:

    parameters:
  mode: active-backup
  primary: enp3s4f0

    to:

    parameters:
  mode: active-backup
  primary: enp3s4f0
  arp-interval: 10
  arp-ip-targets: 10.0.10.10

    Now when the camera goes offline, the bond0 successfully switches over to the other switch, and gets the camera back online.

    • 2