5.6.2 Ensure use of VPC-native clusters (Automated)
Profile Applicability
Description
Create Alias IPs for the node network CIDR range in order to subsequently configure IP-based policies and firewalling for pods. A cluster that uses Alias IPs is called a VPC-native cluster.
Rationale
Using Alias IPs has several benefits:
- Pod IPs are reserved within the network ahead of time, which prevents conflict with other compute resources.
- The networking layer can perform anti-spoofing checks to ensure that egress traffic is not sent with arbitrary source IPs.
- Firewall controls for Pods can be applied separately from their nodes.
- Alias IPs allow Pods to directly access hosted services without using a NAT gateway.
Impact
You cannot currently migrate an existing cluster that uses routes for Pod routing to a cluster that uses Alias IPs.
Cluster IPs for internal services remain only available from within the cluster. If you want to access a Kubernetes Service from within the VPC, but from outside of the cluster, use an internal load balancer.
Audit
Using Google Cloud Console:
- Go to Kubernetes Engine by visiting: https://console.cloud.google.com/kubernetes/list.
- From the list of clusters, click on the desired cluster to open the Details page. Under the 'Networking' section, make sure 'VPC-native traffic routing' is set to 'Enabled'.
Using Command Line:
To check Alias IP is enabled for an existing cluster, first define 2 variables Cluster Name and Zone and then run the following command:
gcloud container clusters describe $CLUSTER_NAME --zone $COMPUTE_ZONE --format json | jq '.ipAllocationPolicy.useIpAliases'
The output of the above command should return
{
"useIpAliases": true
}
if VPC-native (using alias IP) is enabled. If VPC-native (using alias IP) is disabled, the above command will return null ({ }).
Remediation
Alias IPs cannot be enabled on an existing cluster. To create a new cluster using Alias IPs, follow the instructions below.
Using Google Cloud Console:
If using Standard configuration mode:
- Go to Kubernetes Engine by visiting: https://console.cloud.google.com/kubernetes/list.
- Click
CREATE CLUSTER, and select Standard configuration mode.
- Configure your cluster as desired, then, click
Networking under CLUSTER in the navigation pane.
- In the 'VPC-native' section, leave 'Enable VPC-native (using alias IP)' selected.
- Click CREATE.
Using Command Line
To enable Alias IP on a new cluster, run the following command:
gcloud container clusters create <cluster_name> --zone <compute_zone> --enable-ip-alias
Default Value
By default, VPC-native (using alias IP) is enabled when you create a new cluster. The exception is clusters created before GKE version 1.21.0-gke.1500 (September 2021) using the gcloud CLI without --enable-ip-alias."
References
- https://cloud.google.com/kubernetes-engine/docs/how-to/alias-ips
- https://cloud.google.com/kubernetes-engine/docs/concepts/alias-ips
CIS Controls
| Controls Version | Control | IG 1 | IG 2 | IG 3 |
|---|
| v8 | 13.4 Perform Traffic Filtering Between Network Segments | | x | x |
| v7 | 11 Secure Configuration for Network Devices, such as Firewalls, Routers and Switches | | | |
| v7 | 14.1 Segment the Network Based on Sensitivity | | x | x |