k8s Service类型区别

1. ClusterIP Exposes the Service on a cluster-internal IP. This is the default ServiceType.

2. NodePort ServiceType. When kubernetes creates a NodePort service, kube-proxy allocates a port in the range 30000-32767 and opens this port on the eth0 interface of every node (the NodePort). Connections to this port are then forwarded to the service’s cluster IP. A gateway router typically sits in front of the cluster and forwards packets to the node.

3.Services of type LoadBalancer have some limitations. They cannot do TLS termination, do virtual hosts or path-based routing, so you can’t use a single load balancer to proxy to multiple services. These limitations led to the addition in Kubernetes v1.2 of a separate kubernetes resource called Ingress and Route (on OpenShift).

4. ExternalName Maps the Service to the contents of the externalName field (e.g. foo.bar.example.com), by returning a CNAME record.

You can also use Ingress in addition to Service to expose HTTP/HTTPS Services. Ingress however is technically not a ServiceType. It acts as the entry point for your cluster and lets you consolidate routing rules into a single resource.