Configuration of Gateways to the External Network

Pods in the Kube-OVN network access the network outside the cluster through gateways. Currently, two types of gateways are supported. You can adjust the gateway type in the subnet.

Distributed gateway

Distributed gateways are the default gateway type of subnets. Each node functions as the gateway for the pods on the current node to access the external network. Data packets are routed to the host network stack through the ovn0 NIC of the local host, and then to the external network based on the routing rules of the host. If natOutgoing is set to true, a pod uses the IP address of the current host machine to access the external network.

The following is an example of configuration on a subnet.

vim distributed.yaml

apiVersion: kubeovn.io/v1
kind: Subnet
metadata:
  name: distributed
spec:
  cidrBlock: 10.166.0.0/16
  default: false
  excludeIps:
  - 10.166.0.1
  gateway: 10.166.0.1
  gatewayType: distributed
  natOutgoing: true

kubectl create -f distributed.yaml

Centralized gateway
If you want to use a static IP address to access the external network from a subnet for security operations such as auditing and trustlisting, you can configure a centralized gateway in the subnet. In centralized gateway mode, data packets of a pod are first routed to the ovn0 NIC of a specified node and then to the external network based on the routing rules of the host. If natOutgoing is set to true, a pod uses the IP address of a specified host machine to access the external network.

The following is an example of configuration on a subnet.
```
vim centralized.yaml
```
```
apiVersion: kubeovn.io/v1
kind: Subnet
metadata:
  name: centralized
spec:
  cidrBlock: 10.166.0.0/16
  default: false
  excludeIps:
  - 10.166.0.1
  gateway: 10.166.0.1
  gatewayType: centralized
  gatewayNode: "node1,node2"
  natOutgoing: true
```
```
kubectl create -f centralized.yaml
```

Parent topic: Subnet Management