Change default network type

Because overlay and underlay network can exist in one cluster at the same time, we need to specify the default network type in Hybridnet cluster. Default network type affects the creation of Pods which have none specified Network or network type.

To specify the default network, we need to change the environment variable DEFAULT_NETWORK_TYPE of hybridnet-manager and hybridnet-webhook Pods as follows:

spec:
  containers:
    - name: hybridnet-manager            # or "- name: hybridnet-webhook"
      command:
        - /hybridnet/hybridnet-manager   # or "- /hybridnet/hybridnet-webhook"
      env:
        - name: DEFAULT_NETWORK_TYPE
          value: Overlay                 # "Overlay" or "Underlay", default "Underlay" if environment variable not configured. 

If you started with Getting Started, or you are using the hybridnet online helm chart, operations should be much easier:

# Change default network type to Underlay
helm upgrade hybridnet hybridnet/hybridnet -n kube-system --set defaultNetworkType=Underlay

Changing default network type is a runtime capability, it only effects the Pods which are created after the change.