一，利用rs.reconfig，来添加，删除节点

1，添加节点

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}]};  //添加节点 
 
repmore:PRIMARY> rs.reconfig(config);  //使配置生效 
 
repmore:PRIMARY> rs.status();   //查看节点状态