Kubernetes中ClusterIP、NodePort和LoadBalancer服务类型的区别是什么?

问题1:我正在阅读文档，我对其中的措辞有点困惑。它说:

ClusterIP: Exposes the service on a cluster-internal IP. Choosing this value makes the service only reachable from within the cluster. This is the default ServiceType NodePort: Exposes the service on each Node’s IP at a static port (the NodePort). A ClusterIP service, to which the NodePort service will route, is automatically created. You’ll be able to contact the NodePort service, from outside the cluster, by requesting <NodeIP>:<NodePort>. LoadBalancer: Exposes the service externally using a cloud provider’s load balancer. NodePort and ClusterIP services, to which the external load balancer will route, are automatically created.

NodePort服务类型是否仍然使用ClusterIP，但只是在一个不同的端口上，该端口对外部客户端开放?所以在这种情况下，<NodeIP>:<NodePort>与<ClusterIP>:<NodePort>?

或者NodeIP实际上是运行kubectl get节点时找到的IP，而不是用于ClusterIP服务类型的虚拟IP ?

问题2 -图表中也有下面的链接:

客户端在节点内部有什么特别的原因吗?我假设它需要在ClusterIP服务类型的情况下，ClusterIP服务类型?

如果为NodePort绘制相同的图，那么将客户端完全画在节点和集群之外是否有效?还是我完全错过了重点?

当前回答

`Feature`	`ClusterIP`	`NodePort`	`LoadBalancer`
Exposition	Exposes the Service on an internal IP in the cluster.	Exposing services to external clients	Exposing services to external clients
Cluster	This type makes the Service only reachable from within the cluster	A NodePort service, each cluster node opens a port on the node itself (hence the name) and redirects traffic received on that port to the underlying service.	A LoadBalancer service accessible through a dedicated load balancer, provisioned from the cloud infrastructure Kubernetes is running on
Accessibility	It is default service and Internal clients send requests to a stable internal IP address.	The service is accessible at the internal cluster IP-port, and also through a dedicated port on all nodes.	Clients connect to the service through the load balancer’s IP.
Yaml Config	`type: ClusterIP`	`type: NodePort`	`type: LoadBalancer`
Port Range	Any public ip form Cluster	30000 - 32767	Any public ip form Cluster
User Cases	For internal communication	Best for testing public or private access or providing access for a small amount of time.	widely used For External communication

来源:

Kubernetes在行动 Kubernetes。io服务 Kubernetes Services简单直观地解释了

2021-06-11 04:07:33

其他回答

ClusterIP公开了以下内容:

spec.clusterIp: spec.ports [*] .port

您只能在集群内访问此服务。可以从它的spec.clusterIp端口访问它。如果使用spec.ports[*]. xml文件。targetPort被设置，它将从端口路由到targetPort。调用kubectl get services时得到的cluster -IP是在集群内部分配给该服务的IP。

NodePort公开了以下内容:

< NodeIP >: spec.ports [*] .nodePort spec.clusterIp: spec.ports [*] .port

如果您从节点的外部IP访问nodePort上的这个服务，它将把请求路由到spec.clusterIp:spec.ports[*]。端口，这将反过来路由到您的spec.ports[*]。如果设置了targetPort。该服务的访问方式与ClusterIP相同。

nodeip是节点的外部IP地址。您无法从spec.clusterIp:spec.ports[*]. nodeport访问您的服务。

LoadBalancer公开以下内容:

spec.loadBalancerIp: spec.ports [*] .port < NodeIP >: spec.ports [*] .nodePort spec.clusterIp: spec.ports [*] .port

您可以从负载均衡器的IP地址访问此服务，该IP地址将请求路由到nodePort, nodePort又将请求路由到clusterIP端口。您可以像访问NodePort或ClusterIP服务一样访问这个服务。

2017-01-06 17:03:27

下面是关于图表的问题2的答案，因为它似乎仍然没有直接回答:

客户端在节点内部有什么特别的原因吗?我假设它需要在ClusterIP的情况下在ClusterIP中服务类型?

At the diagram the Client is placed inside the Node to highlight the fact that ClusterIP is only accessible on a machine which has a running kube-proxy daemon. Kube-proxy is responsible for configuring iptables according to the data provided by apiserver (which is also visible at the diagram). So if you create a virtual machine and put it into the network where the Nodes of your cluster are and also properly configure networking on that machine so that individual cluster pods are accessible from there, even with that ClusterIP services will not be accessible from that VM, unless the VM has it's iptables configured properly (which doesn't happen without kubeproxy running on that VM).

如果为NodePort绘制了相同的图，那么绘制是否有效客户端完全外部的节点和集群或我完全没抓住重点?

在节点和集群外部绘制客户端是有效的，因为NodePort可以被任何能够访问集群节点和相应端口的机器访问，包括集群外部的机器。

2022-06-14 07:47:12

不要忘记“new”服务类型(来自k8s文档):

ExternalName:通过返回带有值的CNAME记录，将服务映射到ExternalName字段的内容(例如，foo.bar.example.com)。没有设置任何类型的代理。

注意:使用ExternalName类型需要kube-dns版本1.7或CoreDNS版本0.0.8或更高版本。

2020-09-13 11:39:02

实际的理解。

我已经为NodePort和ClusterIP创建了2个服务

如果我想访问集群内的服务(从主节点或任何工作节点)，那么两者都是可访问的。

现在，如果我想从集群外部访问服务，那么只能访问Nodeport，不能访问ClusterIP。

在这里你可以看到localhost不会监听端口80，即使我的nginx容器监听端口80。