Kubernetes API Server core function is to provide a variety of resources Kubernetes objects (Pod, RC, Service, etc.) and Watch CRUD interfaces such as HTTP Rest, become the central hub of communication and data exchange between various functional modules in the cluster, is the system data bus and the data center.
(1) is a cluster management API entry
(2) is an inlet control resource quota
(3) provides a comprehensive security cluster
1.1 Overview
API server provides services through kube-apiserver process, and then run the master node, using port 8080 by default.
1.2 unique kubernetes Proxy API Interface
API server also provides special REST interface -kubernetes Proxy API interfaces, the role of a proxy REST request that Kubernetes API Server REST requests received to be forwarded to the REST interface kubelet daemon on a Node, a process that Kubelet responsible for corresponding.
Communication between 1.3 cluster function module
Various functional modules in the cluster information is stored by the API Server ETCD, when the need to obtain and manipulate data, (with GET, LIST, WATCH method) implemented by the interface REST API Server provided. Thereby achieving information exchange between the modules.
Interactive, kubelet on each Node API Server node kubelet and periodic reports its status. API server update to etcd in. kubelet by listening watch apiserver pod interface information corresponding to the operation done.
kube-controller-manager and API Server interaction. Watch Interface kube-controller-manager module is provided by the Controller Node API Server, Node real-time monitoring information, and treated accordingly.
kube-scheduler and API Server interaction, when the Scheduler, to listen to the new pod information Watch API Server, it will retrieve a list of Node meet the requirements, begin pod scheduling logic. After the successful scheduling pod bind to a target node