# Load the bonding module
sudo modprobe bonding

# Verify it loaded
lsmod | grep bonding

# Make it persistent
echo "bonding" | sudo tee /etc/modules-load.d/bonding.conf

# Back up existing config
sudo cp /etc/netplan/00-installer-config.yaml /etc/netplan/00-installer-config.yaml.bak

# Find your interface names
ip link show

# /etc/netplan/00-bonding.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      dhcp4: false
    eth1:
      dhcp4: false
  bonds:
    bond0:
      interfaces:
        - eth0
        - eth1
      addresses:
        - 192.168.1.100/24
      routes:
        - to: default
          via: 192.168.1.1
      nameservers:
        addresses:
          - 8.8.8.8
          - 8.8.4.4
      parameters:
        mode: active-backup
        primary: eth0
        mii-monitor-interval: 100    # Check link every 100ms
        fail-over-mac-policy: active # Use active slave's MAC

sudo netplan apply

# Verify the bond is active
cat /proc/net/bonding/bond0
ip addr show bond0

# Create the bond master interface
sudo nmcli connection add \
  type bond \
  con-name bond0 \
  ifname bond0 \
  bond.options "mode=active-backup,miimon=100,primary=eth0"

# Assign a static IP to the bond
sudo nmcli connection modify bond0 \
  ipv4.method manual \
  ipv4.addresses 192.168.1.100/24 \
  ipv4.gateway 192.168.1.1 \
  ipv4.dns "8.8.8.8,8.8.4.4"

# Add slave interfaces to the bond
sudo nmcli connection add \
  type ethernet \
  con-name bond0-slave-eth0 \
  ifname eth0 \
  master bond0

sudo nmcli connection add \
  type ethernet \
  con-name bond0-slave-eth1 \
  ifname eth1 \
  master bond0

# Bring up the bond
sudo nmcli connection up bond0
sudo nmcli connection up bond0-slave-eth0
sudo nmcli connection up bond0-slave-eth1

# Verify
nmcli device status
cat /proc/net/bonding/bond0

# Create the bond interface config
sudo tee /etc/sysconfig/network-scripts/ifcfg-bond0 > /dev/null <<'EOF'
DEVICE=bond0
TYPE=Bond
BONDING_MASTER=yes
BOOTPROTO=none
ONBOOT=yes
IPADDR=192.168.1.100
NETMASK=255.255.255.0
GATEWAY=192.168.1.1
DNS1=8.8.8.8
BONDING_OPTS="mode=active-backup miimon=100 primary=eth0"
EOF

# Configure the first slave
sudo tee /etc/sysconfig/network-scripts/ifcfg-eth0 > /dev/null <<'EOF'
DEVICE=eth0
TYPE=Ethernet
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
EOF

# Configure the second slave
sudo tee /etc/sysconfig/network-scripts/ifcfg-eth1 > /dev/null <<'EOF'
DEVICE=eth1
TYPE=Ethernet
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
EOF

# Restart networking
sudo systemctl restart NetworkManager
# or:
sudo ifup bond0

# /etc/netplan/00-lacp.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    eth0:
      dhcp4: false
    eth1:
      dhcp4: false
  bonds:
    bond0:
      interfaces:
        - eth0
        - eth1
      addresses:
        - 192.168.1.100/24
      routes:
        - to: default
          via: 192.168.1.1
      parameters:
        mode: 802.3ad
        lacp-rate: fast           # Send LACPDU every 1s (vs 30s for slow)
        mii-monitor-interval: 100
        transmit-hash-policy: layer3+4   # Hash on IP+port for better distribution
        ad-select: bandwidth      # Select aggregation based on bandwidth

sudo netplan apply

# Verify LACP is negotiating
cat /proc/net/bonding/bond0
# Should show "LACP actor/partner info" sections and both ports as "Aggregator"

# Check LACP status on Cisco switch:
# show etherchannel summary
# show lacp neighbor

# Create the team master
sudo nmcli connection add \
  type team \
  con-name team0 \
  ifname team0 \
  team.config '{"runner":{"name":"activebackup"},"link_watch":{"name":"ethtool"}}'

# Assign IP to team0
sudo nmcli connection modify team0 \
  ipv4.method manual \
  ipv4.addresses 192.168.1.100/24 \
  ipv4.gateway 192.168.1.1

# Add ports to the team
sudo nmcli connection add \
  type team-slave \
  con-name team0-port1 \
  ifname eth0 \
  master team0

sudo nmcli connection add \
  type team-slave \
  con-name team0-port2 \
  ifname eth1 \
  master team0

# Bring up the team
sudo nmcli connection up team0
sudo nmcli connection up team0-port1
sudo nmcli connection up team0-port2

# Check team status
sudo teamdctl team0 state
sudo teamdctl team0 config dump

# Start a continuous ping in the background
ping -i 0.2 8.8.8.8 &

# Check current active interface
cat /proc/net/bonding/bond0 | grep "Currently Active Slave"
# Output: Currently Active Slave: eth0

# Simulate a link failure by bringing down the active interface
sudo ip link set eth0 down

# Watch the bond failover (should take ~miimon ms)
cat /proc/net/bonding/bond0 | grep "Currently Active Slave"
# Output: Currently Active Slave: eth1

# Verify no ping drops (or minimal drops with active-backup)
# The ping in the background should continue uninterrupted

# Restore the interface
sudo ip link set eth0 up

# Check that eth0 rejoins as backup
cat /proc/net/bonding/bond0

# Kill the background ping
kill %1

# Verify the bonding module is loaded
lsmod | grep bonding

# Check for Netplan/NetworkManager errors
sudo netplan --debug apply 2>&1
sudo journalctl -u NetworkManager -n 50

# Slaves must not have IP addresses configured directly
# Check for conflicting config
ip addr show eth0

# For NetworkManager, verify the slave connection references the master
nmcli connection show bond0-slave-eth0 | grep master

# Verify LACP is enabled on the switch port
# Check bond status for LACP partner info
cat /proc/net/bonding/bond0 | grep -A 5 "Partner"
# If partner shows all zeros, LACP is not enabled on the switch

# Temporarily test with mode=balance-xor to verify physical connectivity first

# Check transmit hash policy
cat /proc/net/bonding/bond0 | grep "Transmit Hash Policy"

# layer2 (default): hashes on MAC addresses only — may not balance well
# layer3+4: hashes on IP + port — better distribution for varied flows
sudo nmcli connection modify bond0 bond.options "mode=802.3ad,xmit_hash_policy=layer3+4"