今天有个etl开发在drop partition的时候遇到了问题，因为是使用了自己的账号，而hdfs中对应partition的文件属主是hdfs的，在删除时会因为权限问题报错，切换用户为hdfs，做drop partition的错误，还是报错，看来没这么简单。
查看表的hdfs属性，目录的属主不是hdfs且目录对 hdfs没有写权限:
[hdfs@nfzm ~]$ hadoop fs -ls -d hdfs://xxxx:9000/bip/external_table/vipdw/droptest Found 1 items drwxr-x r-x - ericni hdfs 0 2014-08-21 17:13 hdfs://xxxxx:9000/bip/external_table/vipdw/droptest
drop partition报错,报hdfs用户没有权限，在hive中是设置了hdfs为超级管理员的，所以如果直接用hadoop fs命令是可以删除的，也就是权限问题不是出在hdfs上，而是在hive上，这里怎么会没有权限呢？
hive (vipdw)> ALTER TABLE droptest DROP PARTITION(dt=‘20140840‘); 14/08/21 17:31:21 ERROR metastore.RetryingHMSHandler: MetaException(message:Table partition not deleted since hdfs://xxxx:9000/bip/external_table/vipdw/droptest is not writable by hdfs
根据调用信息，异常是在HiveMetaStore类中的verifyIsWritablePath 方法中抛出， verifyIsWritablePath类用来判断本目录的上层目录对当前用户是否可写，按照一般的思路，所有的hdfs目录都应该对超级管理员可写的。
private void verifyIsWritablePath(Path dir) throws MetaException {
try {
if (!wh.isWritable(dir.getParent())) {
throw new MetaException("Table partition not deleted since " + dir.getParent()
+ " is not writable by " + hiveConf.getUser());
}
} catch (IOException ex) {
LOG.warn("Error from isWritable", ex);
throw new MetaException("Table partition not deleted since " + dir.getParent()
+ " access cannot be checked: " + ex.getMessage());
}
}这里判断调用了 Warehouse类的isWritable 的方法，但是实现方法有些问题，不会区分超级用户，只会根据目录的属主和属组的权限做判断。
public boolean isWritable(Path path) throws IOException {
if (!storageAuthCheck) {
// no checks for non-secure hadoop installations
return true;
}
if (path == null) { //what??!!
return false;
}
final FileStatus stat;
try {
stat = getFs(path).getFileStatus(path);
} catch (FileNotFoundException fnfe){
// File named by path doesn‘t exist; nothing to validate.
return true;
} catch (Exception e) {
// all other exceptions are considered as emanating from
// unauthorized accesses
return false;
}
final UserGroupInformation ugi;
try {
ugi = ShimLoader.getHadoopShims().getUGIForConf(conf);
} catch (LoginException le) {
throw new IOException(le);
}
String user = ShimLoader.getHadoopShims().getShortUserName(ugi);
//check whether owner can delete
if (stat.getOwner().equals(user) &&
stat.getPermission().getUserAction().implies(FsAction.WRITE)) { // 判断属主有没有写权限
return true;
}
//check whether group of the user can delete
if (stat.getPermission().getGroupAction().implies(FsAction.WRITE)) { // 判断属组有没有有写权限
String[] groups = ugi.getGroupNames();
if (ArrayUtils.contains(groups, stat.getGroup())) {
return true;
}
}
//check whether others can delete (uncommon case!!) // // 判断other有没有写权限
if (stat.getPermission().getOtherAction().implies(FsAction.WRITE)) {
return true;
}
return false;
}fix这个bug也比较简单：
git diff
diff --git a/metastore/src/java/org/apache/hadoop/hive/metastore/Warehouse.java b/metastore/src/java/org/apache/hadoop/hive/metastor
index a4f9b0a..c69e49d 100755
--- a/metastore/src/java/org/apache/hadoop/hive/metastore/Warehouse.java
+++ b/metastore/src/java/org/apache/hadoop/hive/metastore/Warehouse.java
@@ -263,7 +263,17 @@ public boolean isWritable(Path path) throws IOException {
}
String user = ShimLoader.getHadoopShims().getShortUserName(ugi);
//check whether owner can delete
- if (stat.getOwner().equals(user) &&
+
+ //fix hdfs drop partition bug
+ LOG.warn("in Warehouse user is " + user);
+ String adminStr = HiveConf.getVar(conf,HiveConf.ConfVars.USERS_IN_ADMIN_ROLE,"hdfs").trim();
+ LOG.warn("adminStr is " + adminStr);
+ if (user.equals(adminStr)){
+ return true;
+ }
+
+
+ if (stat.getOwner().equals(user) &&
stat.getPermission().getUserAction().implies(FsAction.WRITE)) {
return true;
}本文出自 “菜光光的博客” 博客，请务必保留此出处http://caiguangguang.blog.51cto.com/1652935/1543652
原文地址：http://caiguangguang.blog.51cto.com/1652935/1543652
