You can define multiple ones on demand.

DEF_NIC=$(ip r get 1 | head -n1 | awk '{ print $5 }')
# double check the default NIC
echo $DEF_NIC

# the type is macvlan and use static for ip management
# change the ADDRESS and GATEWAY accordingly
ADDRESS=10.67.108.35/23
GATEWAY=10.67.108.1
cat <<EOF > macvlan-static-net.yaml
apiVersion: "k8s.cni.cncf.io/v1"
kind: NetworkAttachmentDefinition
metadata:
  name: macvlan-static
spec:
  config: '{
      "cniVersion": "0.3.1",
      "type": "macvlan",
      "master": "$DEF_NIC",
      "mode": "bridge",
      "ipam": {
        "type": "static",
        "addresses": [
          { "address": "$ADDRESS", "gateway": "$GATEWAY" }
        ]
      }
    }'
EOF
kubectl create -f macvlan-static-net.yaml