和另一个同学的问题相似
org.apache.hadoop.ipc.RemoteException(java.io.IOException): File /hdfsapi/test/a.txt could only be replicated to 0 nodes instead of minReplication (=1). There are 1 datanode(s) running and 1 node(s) are excluded in this operation.

但是我是在VM上实验的。也是idea里面运行create代码，然后就报了上面的错误。
我参考了baidu到的一些解决方案，感觉和他们的情况不一样。
hadoop dfsadmin -report 运行这句命令后看到如下：

DEPRECATED: Use of this script to execute hdfs command is deprecated.
Instead use the hdfs command for it.

19/05/27 08:02:25 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Configured Capacity: 18700304384 (17.42 GB)
Present Capacity: 16119177216 (15.01 GB)
DFS Remaining: 16119148544 (15.01 GB)
DFS Used: 28672 (28 KB)
DFS Used%: 0.00%
Under replicated blocks: 0
Blocks with corrupt replicas: 0
Missing blocks: 0
Missing blocks (with replication factor 1): 0

-------------------------------------------------
Live datanodes (1):

Name: 10.0.0.14:50010 (hadoop000)
Hostname: localhost
Decommission Status : Normal
Configured Capacity: 18700304384 (17.42 GB)
DFS Used: 28672 (28 KB)
Non DFS Used: 2581127168 (2.40 GB)
DFS Remaining: 16119148544 (15.01 GB)
DFS Used%: 0.00%
DFS Remaining%: 86.20%
Configured Cache Capacity: 0 (0 B)
Cache Used: 0 (0 B)
Cache Remaining: 0 (0 B)
Cache Used%: 100.00%
Cache Remaining%: 0.00%
Xceivers: 1
Last contact: Mon May 27 08:02:26 CST 2019

另外还有一点很奇怪，我mkdir是成功的。