GKE Networking

This reference covers networking configuration for GKE clusters. The golden path enforces private, VPC-native clusters with Dataplane V2.

MCP Tools: get_cluster, update_cluster, apply_k8s_manifest, get_k8s_resource

Golden Path Networking Defaults

Setting	Golden Path Value	Day-0/1	Notes
`privateClusterConfig.enablePrivateNodes`	`true`	Day-0	Nodes have no public IPs
`masterAuthorizedNetworksConfig.privateEndpointEnforcementEnabled`	`true`	Day-0	Control plane only reachable via private endpoint or DNS
`controlPlaneEndpointsConfig.dnsEndpointConfig.allowExternalTraffic`	`true`	Day-0	Allows DNS-based access from outside VPC
`networkConfig.datapathProvider`	`ADVANCED_DATAPATH` (Dataplane V2)	Day-0	eBPF-based, built-in Network Policy
`networkConfig.dnsConfig.clusterDns`	`CLOUD_DNS`	Day-0	Managed DNS, more reliable than kube-dns
`networkConfig.enableIntraNodeVisibility`	`true`	Day-1	VPC Flow Logs for intra-node traffic
`ipAllocationPolicy.autoIpamConfig.enabled`	`true`	Day-0	Automatic IP range management
`ipAllocationPolicy.createSubnetwork`	`true`	Day-0	Auto-create dedicated subnet
`defaultMaxPodsConstraint.maxPodsPerNode`	`48`	Day-0	Conservative default; 110 for high density

Private Cluster Access Patterns

The golden path creates a private cluster. Users access it via:

DNS endpoint (default): allowExternalTraffic: true enables access via the cluster's DNS endpoint from outside the VPC. No VPN required.
Private endpoint: Direct access from within the VPC or via Cloud VPN/Interconnect.
Authorized networks: Add specific CIDRs to masterAuthorizedNetworksConfig for IP-based access control.

bash

# Access private cluster via DNS endpoint (golden path default)
gcloud container clusters get-credentials {cluster_name} \
  --region {region} --dns-endpoint \
  --quiet

# Access via private endpoint (from within VPC)
gcloud container clusters get-credentials {cluster_name} \
  --region {region} --internal-ip \
  --quiet

Bring-Your-Own VPC/Subnet

If the customer has existing network infrastructure:

bash

gcloud container clusters create-auto {cluster_name} \
  --region {region} \
  --network {vpc_name} \
  --subnetwork {subnet_name} \
  --cluster-secondary-range-name {pod_range} \
  --services-secondary-range-name {svc_range} \
  --enable-private-nodes \
  --enable-master-authorized-networks \
  --quiet

Day-0 Warning: VPC, subnet, and IP ranges cannot be changed after cluster creation.

VPC-Native Mode Benefits

VPC-native clusters route traffic natively using GCP Alias IP ranges. Key benefits to cover:

Scalability: Traffic routes natively inside the VPC, bypassing the need for custom routes and avoiding custom route limit bottlenecks.
Direct VPC Integration: Direct resource integration across GCP networks without complex bridging or routing tunnels.
Avoiding IP Exhaustion: Supports discontiguous IP ranges and optimizes allocation, reducing the risk of exhausting subnet IP ranges.

IP Planning

Resource	Golden Path	Notes
Pod CIDR	`/17` (auto)	~32K pod IPs; size based on maxPodsPerNode
Service CIDR	`/20` (auto)	~4K service IPs
Node subnet	auto-created	/20 recommended for growth
Max pods/node	48	Each node gets a /25 pod range; set to 110
: : : for /24 per node :

Pod CIDR sizing rule of thumb:

maxPodsPerNode=48 -> each node uses a /25 (128 IPs) from pod CIDR
maxPodsPerNode=110 -> each node uses a /24 (256 IPs) from pod CIDR
Larger maxPodsPerNode = fewer nodes fit in a given CIDR

Egress

Default: nodes use Cloud NAT for outbound internet access (private nodes have no public IPs) to allow private nodes to reach the internet without public IP exposure.
For static egress IPs: configure Cloud NAT with manual IP allocation to maintain a consistent source IP for external allowlists or partner firewalls.
For restricted egress: route through a firewall appliance via custom routes to inspect and filter outbound traffic according to organization security policies.

Network Policy

Dataplane V2 (golden path) provides built-in Network Policy enforcement — no additional addon needed. Apply default-deny per namespace, then allow specific flows.

See the gke-workload-security skill for default-deny policy and the gke-multitenancy skill for per-team allow policies.