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AWS elastic IP on secondary interface

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We have a problem with ubuntu system with two NICs

In AWS, when we attach an elastic IP to the secondary NIC, we don’t get connectivity while it works out of the box for Amazon Linux and for RedHat 8

Redhat 8 is relying on Network manager while amazon Linux is not

This a workaround provided by Amazon to use source addressing but it is not suitable for our use case as we want to rely on destination-based routing https://aws.amazon.com/premiumsupport/knowledge-center/ec2-ubuntu-secondary-network-interface/

Procedure:

Initialize an AWS ec2 instance using ami-09e67e426f25ce0d7 , add 2 network card and associate the security group

One Launched add an EIP for each interface

Connectivity ok for the main interface, while for the second it doesn’t work unless we enable the source based routing as indicated in the following link https://aws.amazon.com/premiumsupport/knowledge-center/ec2-ubuntu-secondary-network-interface/

What would you advise us as configurations to get the destination based routing functioning for the secondary interfaces ?

I have tried to install network manager in ubuntu, but this wasn’t sufficient to change the behaviour System information : uname -a Linux ip-10-1-10-173 5.4.0-1045-aws #47-Ubuntu SMP Tue Apr 13 07:02:25 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

ubuntu@ip-10-1-10-173:~$ cat /etc/netplan/50-cloud-init.yaml
# This file is generated from information provided by the datasource.  Changes
# to it will not persist across an instance reboot.  To disable cloud-init's
# network configuration capabilities, write a file
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following:
# network: {config: disabled}
network:
    ethernets:
        eth0:
            dhcp4: true
            dhcp4-overrides:
                route-metric: 100
            dhcp6: false
            match:
                macaddress: 0a:da:13:97:96:6f
            set-name: eth0
        eth1:
            dhcp4: true
            dhcp4-overrides:
                route-metric: 200
            dhcp6: false
            match:
                macaddress: 0a:34:10:48:b7:fd
            set-name: eth1
    version: 2

Thanks a lot Best Regards

mangohost

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