This depends on your security requirements. You probably use a cluster with multiple nodes, so there are network links that the traffic cross. Do you use multiple data centers, and how is the network secured between data centers? Is there another organization that operate e.g. network or hardware parts, that perhaps need to inspect the network during network problems? and how much do you trust their operations?
In the end, if the security is enough depends on your requirements. But if you want a high level of security, you should probably use e.g. Istio with mutual TLS between all services within the cluster, harden it with Kubernetes Network Policies and perhaps use a specific gateway for external traffic.
But if you have control over the nodes in your cluster and say that it is enough with the level of security that a private network gives you, that is also fine - it depends on your requirements.
与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…
