Network requirements

Network requirements

External network requirements

GKE on Bare Metal requires an internet connection for operational purposes. GKE on Bare Metal retrieves cluster components from Container Registry and the cluster is registered with Connect.

You can connect to Google using the public internet (with HTTPS), through a Virtual Private Network (VPN), or through a Dedicated Interconnect.

Internal network requirements

GKE on Bare Metal can work with L2 or L3 connectivity between cluster nodes and requires load balancer nodes be in the same L2 domain. The load balancer nodes can be the control plane nodes or a dedicated set of nodes. See Choosing and configuring load balancers for configuration information.

The L2 network requirement applies whether you run the load balancer on the control plane node pool or in a dedicated set of nodes.

The requirements for load balancer machines are:

  • All load balancers for a given cluster are in the same L2 domain.
  • All VIPs must be in the load balancer machine subnet and routable to the gateway of the subnet.
  • Users are responsible to allow ingress load balancer traffic.

Single user cluster deployment with high availability

The following diagram illustrates a number of key networking concepts for GKE on Bare Metal in one possible network configuration.

GKE on Bare Metal typical network configuration

  • The control plane nodes run load balancers, and they are all on the same L2 network, while other connections, including worker nodes, only require L3 connectivity.
  • Configuration files define IP addresses for worker node pools, as well as virtual IP addresses for Services, for ingress and for control plane (Kubernetes API) access.
  • A connection to Google Cloud is also required.

Port usage

This section shows how UDP and TCP ports are used on cluster and load balancer nodes.

Master nodes

ProtocolDirectionPort rangePurposeUsed by
UDPInbound6081GENEVE EncapsulationSelf
TCPInbound22Provisioning and updates of admin cluster nodesAdmin workstation
TCPInbound443Cluster managementAdmin cluster nodes
TCPInbound6443Kubernetes API serverAll
TCPInbound6444Control plane HAAll
TCPInbound2379 - 2380etcd server client APIkube-apiserver, etcd
TCPInbound10250kubelet APISelf, Control plane
TCPInbound10251kube-schedulerSelf
TCPInbound10252kube-controller-managerSelf
TCPBoth4240CNI health checkAll

Worker nodes

ProtocolDirectionPort rangePurposeUsed by
TCPInbound22Provisioning and updates of user cluster nodesAdmin cluster nodes
UDPInbound6081GENEVE EncapsulationSelf
TCPInbound10250kubelet APISelf, Control plane
TCPInbound30000 - 32767NodePort ServicesSelf
TCPBoth4240CNI health checkAll

Load balancer nodes

ProtocolDirectionPort rangePurposeUsed by
UDPInbound6081GENEVE EncapsulationSelf
TCPInbound6444Kubernetes API serverAll
TCPBoth4240CNI health checkAll
TCPInbound7946Metal LB health checkLB nodes
UDPInbound7946Metal LB health checkLB nodes