In Kubernetes, containers are by default in the container network of Kubernetes, which adds a certain cost and latency to network communication. Kubernetes supports placing containers in the host network space, which is manifested in the Pod as hostNetwork being set to true.

PolarDBXCluster also supports placing the containers of nodes in the host network, but with a few limitations:

• The ports that the node needs to listen to are randomly generated, and there is no guarantee of no conflicts.
• During node upgrades, there may be situations where the ports conflict, and manual intervention is required.

The hostNetwork for each component is specified in the corresponding template field, and can be specified separately for:

• spec.topology.gms.template.hostNetwork
• spec.topology.cn.template.hostNetwork
• spec.topology.dn.template.hostNetwork
• spec.topology.cdc.template.hostNetwork