How to download Ranger policies with a read-only user in a secure Ranger deployment

[#1]

Note: This article is all thanks to Sumit Prakash for diving into the Ranger source code and explaining to me how to do this!

When developing new plugins for Ranger, these plugins need to be able to download the corresponding Ranger policies. In a secure Ranger setup (which is the preferred way), you download them via the secure download API endpoint: /plugins/secure/policies/download/{serviceName}

This API requires authentication. In this article, I will highlight how to set up a read-only user to download a policy.

Step 1: Create a read-only user 

As a Ranger administrator, go to Settings > Users/Groups/Roles:

Then, click on Add New User and create a user with the auditor role, as follows :

Step 2: Give download access to this user

In the Ranger home screen, edit the service you want to download (here Hadoop SQL, or it's technical name cm_hive):

Add the recently created user to the policy.download.auth.users configuration:

Step 3: Test the download API

For this, you can run the following curl command:

curl -Lku auditor:[password] -H "Accept: application/json" -H "Content-type:application/json" "https://[ranger_url]:6182/service/plugins/secure/policies/download/cm_hive"

You should get a response that looks like the following:

{"serviceName":"cm_hive","serviceId":5,"policyVersion":10,"policyUpdateTime":1603825207732,"policies":[{"id":7,"guid":"78892229-bea4-421f-85fd-8214e88e3c21","isEnabled":true,"version":1,"service":"cm_hive","name":"all - global","policyType":0,"policyPriority":0,"description":"Policy for all - global","isAuditEnabled":true,"resources":{"global":{"values":["*"],"isExcludes":false,"isRecursive":false}},"policyItems":[{"accesses":[{"type":"select","isAllowed":true},{"type":"update","isAllowed":true},{"type":"create","isAllowed":true},{"type":"drop","isAllowed":true},{"type":"alter","isAllowed":true},{"type":"index","isAllowed":true},{"type":"lock","isAllowed":true},{"type":"all","isAllowed":true},{"type":"read","isAllowed":true},{"type":"write","isAllowed":true},{"type":"repladmin","isAllowed":true},{"type":"serviceadmin","isAllowed":true},{"type":"tempudfadmin","isAllowed":true},{"type":"refresh","isAllowed":true}],"users":["hive","beacon","dpprofiler","hue","admin","impala"],"groups":[],"roles":[],"conditions":[],"delegateAdmin":true},{"accesses":[{"type":"read","isAllowed":true}],"users":["rangerlookup"],"groups":[],"roles":[],"conditions":[],"delegateAdmin":false}],"denyPolicyItems":[],"allowExceptions":[],"denyExceptions":[],"dataMaskPolicyItems":[],"rowFilterPolicyItems":[],"serviceType":"hive","options":{},"validitySchedules":[],"policyLabels":[],"zoneName":"","isDenyAllElse":false},{"id":8,"guid":"211690a6-6fb9-41e1-99ba-bb00a46adedb","isEnabled":true,"version":1,"service":"cm_hive","name":"all - database, table, column","policyType":0,"policyPriority":0,"description":"Policy for all - database, table, column","isAuditEnabled":true,"resources":{"database":{"values":["*"],"isExcludes":false,"isRecursive":false},"column":{"values":["*"],"isExcludes":false,"isRecursive":false},"table":{"values":["*"],"isExcludes":false,"isRecursive":false}},"policyItems":[{"accesses":[{"type":"select","isAllowed":true},{"type":"update","isAllowed":true},{"type":"create","isAllowed":true},{"type":"drop","isAllowed":true},{"type":"alter","isAllowed":true},{"type":"index","isAllowed":true},{"type":"lock","isAllowed":true},{"type":"all","isAllowed":true},{"type":"read","isAllowed":true},{"type":"write","isAllowed":true},{"type":"repladmin","isAllowed":true},{"type":"serviceadmin","isAllowed":true},{"type":"tempudfadmin","isAllowed":true},{"type":"refresh","isAllowed":true}],"users":["hive","beacon","dpprofiler","hue","admin","impala"],"groups":[],"roles":[],"conditions":[],"delegateAdmin":true},{"accesses":[{"type":"read","isAllowed":true}],"users":["rangerlookup"],"groups":[],"roles":[],"conditions":[],"delegateAdmin":false},{"accesses":[{"type":"all","isAllowed":true},{"type":"drop","isAllowed":true},{"type":"serviceadmin","isAllowed":true},{"type":"select","isAllowed":true},{"type":"read","isAllowed":true},{"type":"update","isAllowed":true},{"type":"create","isAllowed":true},{"type":"index","isAllowed":true},{"type":"lock","isAllowed":true},{"type":"refresh","isAllowed":true},{"type":"repladmin","isAllowed":true},{"type":"write","isAllowed":true},{"type":"alter","isAllowed":true}],"users":["{OWNER}"],"groups":[],"roles":[],"conditions":[],"delegateAdmin":true}],"denyPolicyItems":[],"allowExceptions":[],"denyExceptions":[],"dataMaskPolicyItems":[],"rowFilterPolicyItems":[],"serviceType":"hive","options":{},"validitySchedules":[],"policyLabels":[],"zoneName":"","isDenyAllElse":false},{"id":9,"guid":"3b6489dd-e76d-408f-bac0-c5cba4bdb2ac","isEnabled":true,"version":1,"service":"cm_hive","name":"all - database, table","policyType":0,"policyPriority":0,"description":"Policy for all - database, table","isAuditEnabled":true,"resources":{"database":{"values":["*"],"isExcludes":false,"isRecursive":false},"table":{"values":["*"],"isExcludes":false,"isRecursive":false}},"policyItems":[{"accesses":[{"type":"select","isAllowed":true},{"type":"update","isAllowed":true},{"type":"create","isAllowed":true},{"type":"drop","isAllowed":true},{"type":"alter","isAllowed":true},{"type":"index","isAllowed":true},{"type":"lock","isAllowed":true},{"type":"all","isAllowed":true},{"type":"read","isAllowed":true},{"type":"write","isAllowed":true},{"type":"repladmin","isAllowed":true},{"type":"serviceadmin","isAllowed":true},{"type":"tempudfadmin","isAllowed":true},{"type":"refresh","isAllowed":true}],"users":["hive","beacon","dpprofiler","hue","admin","impala"],"groups":[],"roles":[],"conditions":[],"delegateAdmin":true},{"accesses":[{"type":"read","isAllowed":true}],"users":["rang [...]

[#2]

Thanks Paul, very helpful for when setting up external clients and minimizing the privileges they have in Ranger.