unknown-mac-unicast-action.md

Service BD - Unknown MAC unicast action

Table of contents

• Overview
• Mechanism
• Examples

Overview

The forwarding behavior for unknown unicast traffic within Service Bridge Domain (BD) used in Kubernetes Loadbalancer type services and SNAT feature is set to proxy mode by default to avoid flooding. It can be reverted to the earlier flood mode by setting parameter unknown_mac_unicast_action in the acc provision input file.

Mechanism

Add following configuration in the acc provision input file:

kube_config:
  unknown_mac_unicast_action: "flood"  # default is "proxy"

Run acc-provision tool on updated acc provision input file to generate new aci_deployment.yaml

acc-provision -c <acc_provision_input_file> -f <flavor> -u <apic_username> -p <apic_password> -o aci_deployment.yaml

Delete old aci_deployment.yaml and wait till all the pods in the aci-containers-system namespace are deleted

$ oc delete -f aci_deployment.yaml
$ oc get pods -n aci-containers-system

Apply newly generated aci_deployment.yaml and wait till all pods in aci-containers-system namespace are running

$ oc apply -f aci_deployment.yaml
$ oc get pods -n aci-containers-system

Verify the flag is set in aci-containers-config config map:

$ oc get cm -n aci-containers-system aci-containers-config -oyaml | less
apiVersion: v1
data:
  controller-config: |-
    {
        ...
        "unknown-mac-unicast-action": "flood",
        ...
    }
  ...
  ...

Examples

1. Service BD L2 Unknown Unicast action proxy (default)

2. Service BD L2 Unknown Unicast action flood

kube_config:
  unknown_mac_unicast_action: "flood"