Network Gateway for GDC is the key component for enabling advanced networking features in on-premises clusters. It's a bundled gateway that gives you fine-grained control over the attributes of your cluster network.
An important benefit of the gateway is the dynamic allocation of
floating IP addresses from a set of addresses that you specify in a
NetworkGatewayGroup custom resource. If the infrastructure reboots or resets,
the floating IP address capability ensures that it comes back with the same IP
address. This capability is key while creating a VPN tunnel, running features
like Egress NAT, or when speaking BGP, all of which depend on deterministic IP
addresses.
The egress NAT gateway configuration instructions in the
GKE on Bare Metal documentation contain an
example
of a configured NetworkGatewayGroup resource.
Network Gateway for GDC supports the following features:
- Flat IP mode
- Egress NAT gateway
- BGP-based Load Balancer
- Multi-cluster connectivity
When advanced networking features, such as egress NAT gateway, assign a floating IP address to a specific node, we call that a gateway node. The network interface on a gateway node is configured with one or more floating IP addresses in addition to the primary IP address of the node. If a gateway node fails, the floating IP addresses are mapped to a different (gateway) node, and the advanced networking features continue to work without disruption.