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    E-MapReduce:FAQ

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    E-MapReduce:FAQ

    Last Updated:Jun 21, 2026

    This topic answers common questions about using Ranger.

    RangerUserSync fails to sync Linux/LDAP users

    • Cause: This issue occurs in E-MapReduce versions 3.23.0 and earlier.

    • Solution: Log on to the emr-header-1 node of the cluster. Manually modify the /etc/ecm/ranger-usersync-conf/ranger-ugsync-site.xml file to set the ranger.usersync.enabled parameter to true. Then, in the EMR console, restart the RangerUserSync component.

    How to sync Unix users to Ranger

    Ranger does not support syncing both LDAP and Unix users in the same cluster. The method for syncing Unix users depends on whether OpenLDAP is deployed in your cluster.

    Without OpenLDAP

    1. On the master node of your E-MapReduce cluster, run the following command to add a user.

      sudo adduser <username>

    2. In the EMR console, navigate to the Ranger service. On the Status tab, find RangerUserSync in the Components list and click Restart in the Actions column.

    3. Verify the sync result.

      1. Log on to the Ranger web UI. For more information, see Access the web UIs of open-source components.

      2. Choose Settings > Users/Groups/Roles.

      3. On the Users tab, verify that the new Unix user appears.

        For example, the test user created in step 1 now appears.

    With OpenLDAP

    If OpenLDAP is deployed in your cluster, it syncs LDAP users by default. To enable Unix user sync, you must manually modify Ranger's configuration parameters as follows:

    1. On the master node of your E-MapReduce cluster, run the following command to add a user.

      sudo adduser <username>

    2. In the EMR console, navigate to the Ranger service. On the Configure tab, find and modify the following parameters:

      • Set the ranger.usersync.sync.source parameter to unix.

      • Set the ranger.usersync.source.impl.class parameter to org.apache.ranger.unixusersync.process.UnixUserGroupBuilder.

    3. When prompted by the console, save the configuration and restart the Ranger service. After the service restarts, Unix users are synced automatically.

    4. Verify the sync result.

      1. Log on to the Ranger web UI. For more information, see Access the web UIs of open-source components.

      2. Choose Settings > Users/Groups/Roles.

      3. On the Users tab, verify that the new Unix user appears.

        For example, the test user created in step 1 now appears.