Azure CNI Bridge doesn't replicate physical interface MAC when interface with lower MAC is attached #751
Description
What happened:
When running CNI in bridge mode, the azure0 bridge will replicate the MAC of the interface attached to it with the lowest MAC address. This issue occurs when a veth pair interface is attached to the bridge with a mac address lower than the mac address of the physical vm nic. As a result, ARP table results can get mangled with the bridge replicating the mac of a veth pair instead of the mac from the physical nic. While this issues isn't present in transparent mode, it does exist in bridge.
What you expected to happen:
How to reproduce it:
This issue occurs when the Azure assigned MAC on the primary interface is assigned with a prefix of 60:, this issue does not occur when the mac on the primary interface starts with the prefix 00:
Orchestrator and Version (e.g. Kubernetes, Docker):
Kubernetes
Operating System (Linux/Windows):
Linux, Ubuntu 18.04
Kernel (e.g. uanme -a for Linux or $(Get-ItemProperty -Path "C:\windows\system32\hal.dll").VersionInfo.FileVersion for Windows):
Anything else we need to know?:
[Miscellaneous information that will assist in solving the issue.]