Hi,
I am unable to create bonding of two network interfaces in RHEL8.2.

When I am disconnecting an ethernet, its not connecting through another one. Its working always with one interface only. I have given the commands used for bond configuration below:-

nmcli con add type bond con-name bond0 ifname bond0 mode active-backup ip4 10.0.2.4/24

nmcli connection show

cat /etc/sysconfig/network-scripts/ifcfg-bond0

nmcli con add type bond-slave ifname enp0s3 master bond0

nmcli con add type bond-slave ifname enp0s8 master bond0

nmcli connection

nmcli connection up bond-slave-enp0s3

nmcli connection up bond-slave-enp0s8

nmcli con up bond0

cat /proc/net/bonding/bond0

[root@centos8 ~]# ip link set enp0s3 up
[root@centos8 ~]# cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None
Currently Active Slave: enp0s3
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0
Peer Notification Delay (ms): 0

Slave Interface: enp0s8
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 1
Permanent HW addr: 08:00:27:37:38:f2
Slave queue ID: 0

Slave Interface: enp0s3
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 1
Permanent HW addr: 08:00:27:b1:9b:82
Slave queue ID: 0
[root@centos8 ~]# ip link set enp0s8 down
[root@centos8 ~]# cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None
Currently Active Slave: enp0s3
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0
Peer Notification Delay (ms): 0

Slave Interface: enp0s8
MII Status: down
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:37:38:f2
Slave queue ID: 0

Slave Interface: enp0s3
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 1
Permanent HW addr: 08:00:27:b1:9b:82
Slave queue ID: 0
[root@centos8 ~]# ip link set enp0s8 up
[root@centos8 ~]# ip link set enp0s3 down
[root@centos8 ~]# cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None
Currently Active Slave: enp0s8
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0
Peer Notification Delay (ms): 0

Slave Interface: enp0s8
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:37:38:f2
Slave queue ID: 0

Slave Interface: enp0s3
MII Status: down
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:b1:9b:82
Slave queue ID: 0
[root@centos8 ~]# ip link set enp0s8 up
[root@centos8 ~]# cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None
Currently Active Slave: enp0s8
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0
Peer Notification Delay (ms): 0

Slave Interface: enp0s8
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:37:38:f2
Slave queue ID: 0

Slave Interface: enp0s3
MII Status: down
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:b1:9b:82
Slave queue ID: 0
[root@centos8 ~]# ip link set enp0s3 up
[root@centos8 ~]# cat /proc/net/bonding/bond0
Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011)

Bonding Mode: fault-tolerance (active-backup)
Primary Slave: None
Currently Active Slave: enp0s8
MII Status: up
MII Polling Interval (ms): 100
Up Delay (ms): 0
Down Delay (ms): 0
Peer Notification Delay (ms): 0

Slave Interface: enp0s8
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:37:38:f2
Slave queue ID: 0

Slave Interface: enp0s3
MII Status: up
Speed: 1000 Mbps
Duplex: full
Link Failure Count: 2
Permanent HW addr: 08:00:27:b1:9b:82
Slave queue ID: 0
[root@centos8 ~]#

Can any one help me or share the exact steps for bonding configuration?

Thanks

Arvind K