Why Do IP Addresses of Cluster Nodes and of Some System Add-on Pods Start with 30? Is Public Network Access Involved?

Symptom

In the CCE Autopilot cluster, the IP addresses of the nodes and the pods of some system add-ons start with 30, like in the following figures.

Figure 1 Node IP addresses

Figure 2 IP addresses of the system add-on pods

Description

Figure 3 shows how this issue occurs. The details are as follows:

• CCE Autopilot clusters are region-specific. The master and worker nodes in a CCE Autopilot cluster are in the same region where the cluster is deployed, and hosts do not need to be deployed across borders.
• The IP addresses of nodes in a CCE Autopilot cluster and of system add-on pods are from the CIDR block starting with 30. This CIDR block is allocated from the VPC where the cluster control plane is deployed and not used on the public network. The CIDR block starting with 30 is only used by the cluster control plane for internal communications and is completely isolated from the public network. It is not used for hosts to access the public network.

The network planes of a CCE Autopilot cluster include the cluster control plane (service hosting) and container network plane (user-defined management).

• Cluster control plane: used to deploy components related to the cluster control plane, including the master nodes, managed nodes, and some system add-ons. This plane is isolated from the container network plane and does not need to be planned or managed by users.
• Container network plane: used to deploy service pods required by users. This plane is planned and managed by users.

Figure 3 Relationship between the cluster control plane and container network plane