RHEL 9.x/8.x

This package is supported on RHEL, and the RHEL-based distributions such as CentOS Linux, Rocky Linux, and Alma Linux.

NOTE: On RHEL 7.x-based kernels the package installs in backward-compatibility mode: it only provides multipath on NFSv3 mounts.

Here we demonstrate multipath with two local interfaces on the same subnet.

First we need to install NetworkManager-config-routing-rules.

yum install NetworkManager-config-routing-rules

Configuring for multipath with nmcli

Suppose we have a host with two network cards, ib0 and ib1. The network cards are directly connected to the server's switch and belong to the same IP subnet. We need to define source-based routing to the server (with IP 192.168.40.11) to take advantage of multipath mode.

$ nmcli -f 'GENERAL.DEVICE,IP4.ADDRESS' device show
GENERAL.DEVICE:                         enp1s0
IP4.ADDRESS[1]:                         192.168.122.235/24

GENERAL.DEVICE:                         ib0
IP4.ADDRESS[1]:                         192.168.40.1/24

GENERAL.DEVICE:                         ib1
IP4.ADDRESS[1]:                         192.168.40.2/24

GENERAL.DEVICE:                         lo
IP4.ADDRESS[1]:                         127.0.0.1/8

1. Verify that routing tables 101 and 102 are empty:

ip route show table 101
ip route show table 102

2. Add symbolic names for custom routing tables:

echo '101 101' >> /etc/iproute2/rt_tables
echo '102 102' >> /etc/iproute2/rt_tables

3. Add custom routing tables for ib0 and ib1:

nmcli device modify ib0 ipv4.routes "192.168.40.0/24 src=192.168.40.1 table=101"
nmcli device modify ib1 ipv4.routes "192.168.40.0/24 src=192.168.40.2 table=102"

4. Add custom routing rules with priority 100:

nmcli device modify ib0 +ipv4.routing-rules "priority 100 from 192.168.40.1 table 101"
nmcli device modify ib1 +ipv4.routing-rules "priority 100 from 192.168.40.2 table 102"

5. Reload configuration and verify it:

$ nmcli connection reload
$ ip route get 192.168.40.11 from 192.168.40.1
192.168.40.11 from 192.168.40.1 dev ib0 table 101
    cache
$ ip route get 192.168.40.11 from 192.168.40.2
192.168.40.11 from 192.168.40.2 dev ib1 table 102
    cache

6. If needed, troubleshoot with commands:

ip route show table 101
ip route show table 102
ip rule show

Configuring for multipath using old style network-scripts interface

We configure new source routing tables:

echo '101 101' >> /etc/iproute2/rt_tables
echo '102 102' >> /etc/iproute2/rt_tables

For this example we assume two interfaces are configured via ifcfg- scripts:

$ grep IPADDR /etc/sysconfig/network-scripts/ifcfg-ib0
IPADDR=192.168.40.1
$ grep IPADDR /etc/sysconfig/network-scripts/ifcfg-ib1
IPADDR=192.168.40.2

For each interface we need to add a route- and rule- files:

$ cat /etc/sysconfig/network-scripts/route-ib0
192.168.40.0/24 via 192.168.40.1 table 101
$ cat /etc/sysconfig/network-scripts/rule-ib0
from 192.168.40.1/32 table 101

NOTE: This is only an example. The IP addresses you pick depend on your network configuration.

After reloading with nmcli connection reload, the ip command with regard to routing should look like this (notice the two added lookup lines):

$ ip rule
0:      from all lookup local
32764:  from 192.168.40.1 lookup 101
32765:  from 192.168.40.2 lookup 102
32766:  from all lookup main
32767:  from all lookup default

$ ip route show table 101
192.168.40.0/24 via 192.168.40.1 dev ib0

$ ip route show table 102
192.168.40.0/24 via 192.168.40.2 dev ib1

Verify that the IPs and routing tables appear correctly. Below are examples which will vary based on environment:

IP addresses:

$ ip a s | grep 192.168.40

    inet 192.168.40.1/24 brd 192.168.40.255 scope global ib0
    inet 192.168.40.2/24 brd 192.168.40.255 scope global ib1

Document generated on 2025.07.21 14:52 for v4.0.34-21-ga7ed64bc5, branch 4.0