The differences and relationships among port, targetport, nodeport and containerport in kubenetes

1. containerPort

   containerPort Is in pod Defined in the controller 、pod Containers in need of exposed ports .Pod Exposed port in container

2. targetPort

   targetPort yes pod On the port , from port/nodePort The data coming down , after kube-proxy Into the back end pod Of targetPort On , And finally into the container .Pod Exposed ports

3. port

   port Is exposed to cluster ( Cluster network ) On the port , Provides internal cluster client access service Entrance , namely clusterIP:port.mysql The container is exposed 3306 port （ Reference resources DockerFile）, Other containers in the cluster pass through 33306 Port access mysql service , However, external traffic cannot access mysql service , because mysql The service is not configured NodePort.service Ports exposed in the cluster
   

4. nodePort

   nodePort Provides access to external clients of the cluster service One way , namely nodeIP:nodePort Provides external network access k8s In the cluster service Entrance . The port of the cluster exposed in the external network

Reference resources
KUBERNETES NODEPORT、TARGETPORT、PORT、CONTAINERPORT The illustration

K8s Discrimination of miscible points ：nodePort、port、targetPort、containerPort