Calico是一个基于BGP协议的虚拟网络工具，在数据中心中的虚拟机、容器或者裸金属机器（在这里都称为workloads）只需要一个IP地址就可以使用Calico实现互连，calico-3.1.yaml文件，为k8s提供网络支持(Calico is a virtual network based on BGP protocol, in the data center of the virtual machine, the container or the bare metal machine (here called workloads) requires only one IP address can be implemented using Calico interconnection, calico-3.1.yaml file, to provide network support for k8s)