使用WebHDFS创建目录时遇权限错误，求技术协助

Hey there, let's work through why you're hitting that permission denied error when trying to create a directory via WebHDFS.

First, let's break down the error message you received to understand what's going on:

"RemoteException":{"exception":"AccessControlException","javaClassName":"org.apache.hadoop.security.AccessControlException","message":"Permission denied: user=dr.who, access=WRITE, inode="/tempdir":root:supergroup:drwxr-xr-x"}

This tells us three critical details:

• You're accessing WebHDFS as the default anonymous user dr.who (since no authentication was specified in your curl call)
• You're attempting a WRITE operation on the /tempdir directory
• The /tempdir directory is owned by root (group supergroup) with permissions drwxr-xr-x — meaning only the owner has write access; other users like dr.who can only read and execute, not modify or add content.

Here are targeted fixes based on your actual goal: #

1. You meant to create a subdirectory inside /tempdir

If your intent is to make a folder under /tempdir (not create /tempdir itself), adjust your curl command to target the subdirectory path:

curl -i -X PUT "http://myhost:50070/webhdfs/v1/tempdir/mysubdir?op=MKDIRS"

Note: You'll still need write access to /tempdir for this to work — jump to option 2 if you don't have that permission.

2. You need write access to the existing /tempdir

To let dr.who write to /tempdir, you'll need a user with admin/superuser privileges to run one of these commands:

• Quick (less secure) fix: Add write permissions for all other users (good for testing):

  hdfs dfs -chmod o+w /tempdir
  

• Secure fix: Transfer ownership to dr.who (ideal if this directory is meant for their use):

  hdfs dfs -chown dr.who:dr.who /tempdir
  

• Group-based fix: Add write permissions for the supergroup (if dr.who is part of supergroup):

  hdfs dfs -chmod g+w /tempdir
  

3. You want to create /tempdir from scratch (it doesn't exist yet)

If /tempdir doesn't exist, the problem is likely that the root directory (/) blocks anonymous users from creating new folders. Here's how to fix this:

• Ask your Hadoop admin to create /tempdir for you and set permissions that allow dr.who to use it, or
• Authenticate as a user with root directory write access. For example, if using Kerberos, use this curl command to leverage your valid Kerberos ticket:

  curl -i -X PUT --negotiate -u : "http://myhost:50070/webhdfs/v1/tempdir?op=MKDIRS"
  

内容的提问来源于stack exchange，提问作者user5431918