用戶通過哪個ip和端口訪問jupyterhub:通過c.JupyterHub.ip和c.JupyterHub.port來設置
當Proxy 或Spawners是遠程服務時，通過哪個ip和端口來和hub通信：c.JupyterHub.hub_ip和c.JupyterHub.hub_port
當hub在容器里時，可以配置：
c.JupyterHub.hub_ip = '0.0.0.0' # listen on all interfaces
c.JupyterHub.hub_connect_ip = '10.0.1.4' # ip as seen on the docker network. Can also be a hostname.