Network bonding (LACP)

Bonding (link aggregation) combines several physical ports into one logical interface to increase throughput and/or redundancy. 802.3ad (LACP) mode requires a compatible switch configured on the HolyCloud / datacenter side — open a ticket to enable LACP on your dedicated ports.

Prerequisites

• Dedicated server with two NICs on the same VLAN
• Switch configured for LACP (ports in the same port-channel)
• IPMI/KVM access in case of network loss
• Backup of /etc/netplan/*.yaml or /etc/network/interfaces

Check interfaces

ip -br link
ethtool eth0 | grep -i speed
ethtool eth1 | grep -i speed

Debian/Ubuntu with ifupdown

Install ifenslave:

apt update && apt install -y ifenslave

/etc/network/interfaces (example: eth0 + eth1, static IP on bond0):

auto lo
iface lo inet loopback

auto eth0
iface eth0 inet manual
    bond-master bond0
    bond-slave-priority 100

auto eth1
iface eth1 inet manual
    bond-master bond0

auto bond0
iface bond0 inet static
    address 203.0.113.10/24
    gateway 203.0.113.1
    dns-nameservers 1.1.1.1
    bond-mode 802.3ad
    bond-miimon 100
    bond-lacp-rate fast
    bond-slaves eth0 eth1
    bond-xmit-hash-policy layer3+4

Apply:

ifdown bond0 2>/dev/null; ifup bond0
cat /proc/net/bonding/bond0

Netplan (Ubuntu 22.04+)

/etc/netplan/01-bond.yaml:

network:
  version: 2
  ethernets:
    eth0: {}
    eth1: {}
  bonds:
    bond0:
      interfaces: [eth0, eth1]
      parameters:
        mode: 802.3ad
        lacp-rate: fast
        mii-monitor-interval: 100
        transmit-hash-policy: layer3+4
      addresses:
        - 203.0.113.10/24
      routes:
        - to: default
          via: 203.0.113.1
      nameservers:
        addresses: [1.1.1.1, 8.8.8.8]

Test and apply:

netplan try
netplan apply

Verify LACP

cat /proc/net/bonding/bond0
# "802.3ad info" line: aggregator state
# Slave MII Status: up

Switch side (if visible): port-channel must be up with both members active.

Alternative modes (reference)

| Mode | Usage |

|------|--------|

| active-backup | One active link, failover without switch LACP |

| balance-rr | Rare in production |

| 802.3ad | LACP, requires switch config |

Do not configure LACP without prior agreement on ports — link may stay down.

Troubleshooting

| Symptom | Action |

|----------|--------|

| Bond down, slaves up | Check LACP on switch, HolyCloud ticket |

| Only one active slave | Cable, SFP, ethtool ethX |

| No IP after reboot | netplan apply, IPMI console |

Need help?

Include interface MACs, desired mode (LACP), and dedicated server reference in the ticket.