Cluster VPN overview¶
This chapter summarizes Virtual Private Network (VPN) architecture for multi-cloud private networks.
Cloud provided VPN¶
Cloud provided VPN - a VPN option provided by a cloud service provider.
Cloud provided VPN is currently not available on Digital Ocean.
Traffic in CAST AI platform:
In order to access the Virtual Private Cloud (VPC) network of each node CAST AI platform provisions managed Highly Available (HA) VPN gateways.
- VPN Gateway is created on each cloud and adds additional cluster costs.
- Traffic between nodes in different VPC is always encrypted.
- Traffic between nodes in the same VPC is plaintext.
Example with nodes on AWS, AZURE and GCP clouds:
WireGuard VPN¶
WireGuard VPN - CAST AI integrated alternative to Cloud provided VPN. This option is optimized for saving cost.
You can choose between two topologies:
| Topology | Description |
|---|---|
| Full Mesh | Traffic is encrypted between each node even if it is located in the same VPC. |
| Cross Location Mesh | Traffic is encrypted only between nodes in different VPC. |
Traffic in CAST AI platform:
Each node runs a WireGuard kernel module. VPN peers configuration, keys exchange, network interfaces and routing tables are fully managed by the CAST AI platform.
- Each node has public IP for node-to-node communication.
- Firewall rules allow sending/receive UDP packets on 51820 port for each node.
- Each node is assigned a private IP from cloud's VPC subnet range and WireGuard interface IP from 10.4.0.0/16 subnet.
- Traffic between nodes in different VPC is always encrypted.
- Traffic between nodes in the same VPC is encrypted or plaintext depending on topology selection.
Example with nodes on AWS, AZURE, GCP, and DIGITAL OCEAN clouds:
