訪問HDFS報錯:org.apache.hadoop.security.AccessControlException: Permission denied
阿新 • • 發佈:2018-11-13
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; public class TestHDFS { public static void main(String[] args) throws Exception{ Configuration conf = new Configuration(); conf.set("fs.defaultFS", "hdfs://192.168.0.104:9000"); FileSystem fs= FileSystem.get(conf); //存在的情況下會覆蓋之前的目錄 boolean success = fs.mkdirs(new Path("/xiaol")); System.out.println(success); } }
Exception in thread "main" org.apache.hadoop.security.AccessControlException: Permission denied: user=xiaol, access=WRITE, inode="/xiaol":root:supergroup:drwxr-xr-x
網上的方法:
1.在hdfs的配置檔案中,將dfs.permissions.enabled修改為False
2.hadoop fs -chmod 777 /
我覺得這倆方法都是屎
hadoop在訪問hdfs的時候會進行許可權認證,取使用者名稱的過程是這樣的:
讀取HADOOP_USER_NAME系統環境變數,如果不為空,那麼拿它作username,如果為空
讀取HADOOP_USER_NAME這個java環境變數,如果為空
從com.sun.security.auth.NTUserPrincipal或者com.sun.security.auth.UnixPrincipal的例項獲取username。
如果以上嘗試都失敗,那麼丟擲異常LoginException("Can’t find user name")
解決方案:
import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import java.util.Properties; public class TestHDFS { public static void main(String[] args) throws Exception{ Properties properties = System.getProperties(); properties.setProperty("HADOOP_USER_NAME", "root"); Configuration conf = new Configuration(); conf.set("fs.defaultFS", "hdfs://192.168.0.104:9000"); FileSystem fs = FileSystem.get(conf); //存在的情況下會覆蓋之前的目錄 boolean success = fs.mkdirs(new Path("/xiaol")); System.out.println(success); } }