How to query ambari internal variable?

[#1]

Config_Type "ranger-hive-audit" /Config_Key "xasecure.audit.destination.db.jdbc.url" is defined as "{{audit_jdbc_url}}". Where can I find the value of {{audit_jdbc_url}} and how could I change it?

[#2 · Accepted solution]

Whenever you see a property enclosed by {{ }} it means that the value is interpreted dynamically by reading params.py or params_linux.py

E.g., https://github.com/apache/ambari/blob/release-2.2.1-rc2/ambari-server/src/main/resources/common-serv... To change it, you can either modify params*.py to use different logic, edit the value in the Config tab of the UI from the Service Dashboard page, or use configs.sh to edit directly (which calls the API).

[#3]

Thanks. I wonder how Ranger plugins pick up the changes on Ranger. My understanding is that HDFS NN still looks at configuration files in /etc/hadoop/conf. Property xasecure.audit.destination.db.jdbc.url defined in Ranger HDFS NN plugin ranger-hdfs-audit.xml is not changed even though audit_jdbc_url has been changed. The xml file should be changed by Ambari once Ranger DB host is changed.

[#4]

@Alejandro Fernandez does this work the same for Ranger 0.6.0 or is that specific to Ranger 0.4.0?

[#5]

@wayne2chicago

You will need to make changes in multiple places to achieve this:

1. Change the code as pointed by @Alejandro Fernandez: link

2. Now to make this reflect for HDFS, you will need to make similar change at link

3. Same code snippet exists in all service's params_linux.py which supports Ranger. you will need to make changes in all such places.

4. You need to make sure the changes you did reaches to all ambari-agents on deployed cluster. So do these changes to the files at /var/lib/ambari-server/resources/* location on ambari-server host and finally restart ambari-server. This will push changes to all nodes on the cluster.

5 At this point changing Ranger DB host config via Ambari and restarting a HDFS component on a host via Ambari will change "xasecure.audit.destination.db.jdbc.url" in "ranger-hdfs-audit". Same applies for other ranger supported services.