MongoServerError: Cannot add shard1/shard1-server1:27017,shard1-server2:27017,shard1-server3:27017 as a shard since the implicit default write concern on this shard is set to {w : 1}, because number of arbiters in the shard's configuration caused the number of writable voting members not to be strictly more than the voting majority. Change the shard configuration or set the cluster-wide write concern using the setDefaultRWConcern command and try again.
把server3设置为仲裁节点，问题迎刃而解！