Kubernetes Networking
CNI (Calico, Cilium), NetworkPolicies, kube-proxy, CoreDNS, Service mesh basics, troubleshooting DNS latency
1What is a CNI (Container Network Interface) in Kubernetes?
What is a CNI (Container Network Interface) in Kubernetes?
답변
A CNI is a plugin that implements the network interface for containers in Kubernetes. It is responsible for allocating IP addresses to pods and configuring networking to enable pod-to-pod communication. Every Kubernetes cluster requires a CNI to function, and the choice of CNI impacts available network features like NetworkPolicies or performance characteristics.
2What is the main role of kube-proxy in a Kubernetes cluster?
What is the main role of kube-proxy in a Kubernetes cluster?
답변
kube-proxy maintains network rules on each node to enable communication to Kubernetes Services. It implements the Service concept by configuring iptables, IPVS, or nftables rules to route traffic to corresponding pods. Without kube-proxy, Services would not function and applications could not communicate via stable ClusterIP addresses.
3What is the function of CoreDNS in Kubernetes?
What is the function of CoreDNS in Kubernetes?
답변
CoreDNS provides DNS resolution within the Kubernetes cluster, enabling pods to discover Services by name. It automatically resolves names in the format service.namespace.svc.cluster.local to corresponding ClusterIP addresses. CoreDNS is essential for service-to-service communication and has replaced kube-dns since Kubernetes 1.13.
Which type of Kubernetes Service exposes a port on each node of the cluster?
What is the main difference between Calico and Flannel?
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