External Type

This type can be used for both public and service clusters if load balancing and security will be configured using the tools of the cloud provider from which the cluster servers are rented.

When to Use External

Access ports 443 and 80, as well as the ports set in TCP settings (see Routing Services in a Cluster), are opened on all network interfaces of all system nodes, that is, on address 0.0.0.0.

Provider-Side Configuration

You will need to configure the provider's Firewall service in its account. It can be either a separate service or part of the load balancing service. Configuration depends on the provider, but as a rule it remains fairly simple (see Example DigitalOcean Load Balancer Setup).

This is the simplest and least resource-intensive method for clusters with one system node, that is, in cost-saving mode, if the provider provides at least a Firewall service.