一，利用rs.reconfig，來添加，刪除節點

1，添加節點

repmore:PRIMARY> config = {_id:"repmore",members:[{_id:0,host:'127.0.0.1:27017',priority :2},{_id:1,host:'127.0.0.1:27018',priority:1}]};  //添加節點 
 
repmore:PRIMARY> rs.reconfig(config);  //使配置生效 
 
repmore:PRIMARY> rs.status();   //查看節點狀態