Use Ranger with caching and downscoping

Enable caching

This section lists the steps to enable caching with Ranger in order to reduce Ranger Key Management System (KMS) round trips to encrypt and decrypt tokens.

1. Install memcached on Dataproc cluster VMs. By default, the memcached server starts on VM port 11211 ( localhost:11211 ).

   sudo apt-get install -y memcached

2. Set the following properties in the /etc/dataproc-ranger-gcs-plugin/conf/ranger-gcs-site.xml Ranger config file on Dataproc cluster VMs.

   <property>
   <name>authorization.service.remoteCaching.address</name>
   <value>localhost:11211</value>
   </property>
   <property>
   <name>authorization.service.remoteCaching.class</name>
   <value>com.google.cloud.hadoop.ranger.gcs.authorization.caching.MemcachedCache</value>
   </property>
   <property>
   <name>authorization.service.remoteCaching.encryption.key.uri</name>
   <value>gcp-kms://projects/ PROJECT_ID_OF_KMS_KEY 
   /locations/ REGION 
   /keyRings/ KEYRING_NAME 
   /cryptoKeys/ KEY_NAME 
   </value>
   </property>

3. Restart the authorization service.

   sudo systemctl restart ranger-gcs-plugin-authorization-server

View cache status

You can use telnet to view Ranger cache status.

1. Install telnet .

   sudo apt-get install -y telnet

2. Use telnet to connect to memcache on VM port 11211 .

   sudo telnet 127.0.0.1 11211

3. Use telnet commands to view cache status, including the following commands:

   • stats items : List the status of cache items. Sample output:

     STAT items:17:number 2
     STAT items:17:number_hot 0
     STAT items:17:number_warm 0
     STAT items:17:number_cold 2

   • stats cachedump : List keys stored in the cache. Sample output:

     stats cachedump 17 2
     ITEM 0616eeeeb54e23a09505da5bf75cd7fafe733eacf0d07bd7b1ac9cf46d17c188 [3051 b; 1707948281 s]
     ITEM d23645df9c79290d59ddb1b9710ff04fee37aa0b5de866b9b6d56b54641d68b4 [3078 b; 1707948281 s]

   • flush_all : Invalidate cache items.

Downscope Cloud Storage access tokens

You might need to downscope Ranger access tokens to move up (upscope) the Cloud Storage paths that an external Hive table points to.

To move all partitions and subpartitions up to the table level, set the downscope.table.partition-name.pruning.enabled property to true in the ranger-gcs-site.xml config file on Dataproc cluster VMs.

<property>
  <name>downscope.table.partition-name.pruning.enabled</name>
  <value>true</value>
</property>

Example:

• Cloud Storage bucket name: gs://warehouse
• Original access token path: warehouse/hive/table/type=debit/year=2017/month=Aug/day=01/
• After setting downscope.table.partition-name.pruning.enabled to true , upscoped access token path: warehouse/hive/table/