I have set up the docker with hadoop-2.7.0 image that you referred to and I am getting this NPE on the namenode side upon an mkdir attempt that should result in AccessControlException instead of NPE (see below), and I don't see this with my hadoop-2.7.1 installation. This suggests there's something wrong with HDFS in the docker image.
Can you try out the sandbox version in the mean time? We will research this NPE problem in the namenode in the docker image.
java.lang.NullPointerException
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkOwner(FSPermissionChecker.java:247)
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:227)
at org.apache.hadoop.hdfs.server.namenode.FSPermissionChecker.checkPermission(FSPermissionChecker.java:190)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1698)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkPermission(FSDirectory.java:1682)
at org.apache.hadoop.hdfs.server.namenode.FSDirectory.checkOwner(FSDirectory.java:1651)
at org.apache.hadoop.hdfs.server.namenode.FSDirAttrOp.setPermission(FSDirAttrOp.java:61)
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.setPermission(FSNamesystem.java:1653)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.setPermission(NameNodeRpcServer.java:693)
at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.setPermission(ClientNamenodeProtocolServerSideTranslatorPB.java:453)
at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)