User Impersonation for HttpFS

You can set up proxy user functionality if you want HttpFS to impersonate a user from a set of hosts, or to impersonate a user that belongs to a set of groups. When you configure proxy user functionality, the proxy user can perform “doAs” operations. Add configuration properties to the httpfs-site.xml and core-site.xml files to configure proxy user functionality.

Complete the following steps to configure user impersonation for HttpFS:

Add the following configuration properties to the httpfs-site-site.xml file:
- httpfs.proxyuser.#USER#.hosts
- httpfs.proxyuser.#USER#.groups
Replace #USER# with the username of the proxy that can perform “doAs” operations. For the host property, you can add a list of host names as the value. For the group property, you can add a list of groups as the value. Alternatively, you can add a wildcard character (*) as the value for host and group properties. To add multiple users, copy the property and replace #USER# with the proxy user name.
Host Example
```
<property>
        <name>httpfs.proxyuser.mapr.hosts</name>
        <value>*</value>       
</property>
```
Group Example
```
<property>
        <name>httpfs.proxyuser.mapr.groups</name>
        <value>*</value>        
</property>
```

To use impersonation, issue a cURL command with the doas=<impersonated_user's name> parameter.

Example 1

Where user.name is mapr and doas (or the impersonated user's name) is sampleusername.

curl -i -X PUT -T one 
"http://<node_name>:14000/webhdfs/v1/user/mapr/TEST/one
?op=CREATE&user.name=mapr&doas=sampleusername&data=true" 
-H "Content-Type:application/octet-stream"

Example 2

For any user (and password) other than the mapr user (for example, test_user1), set the following property in the /opt/mapr/httpfs/httpfs-1.0/etc/hadoop/httpfs-site.xml file:

<property>
          <name>hadoop.proxyuser.<test_user1>.hosts</name>
          <value>*</value>     
</property>

Run cURL.

Where trueuser.name is test_user1 and doas (or the impersonated user's name) is test_user2.

curl -u fred -i -X PUT -T /etc/hosts --header "Content-Type:application/octet-stream" 
"http://<node_name>:14000/webhdfs/v1/<path_to_test_file>
?op=CREATE&doas=<test_user2>&data=true&user.name=<test_user1>"