Back up and restore a Ranger schema
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This page shows you how to back up and restore a Ranger schema on Dataproc with Ranger clusters.

Before you begin

Create a bucket if needed. You must have access to a Cloud Storage bucket, which you will use to store and restore a Ranger schema.

To create a bucket:
1. In the Google Cloud console, go to the Cloud Storage Buckets page.
  Go to Buckets
2. Click Create.
3. On the Create a bucket page, enter your bucket information. To go to the next step, click Continue.
  1. In the Get started section, do the following:
    - Enter a globally unique name that meets the bucket naming requirements.
    - To add a bucket label, expand the Labels section (), click Add label, and specify a key and a value for your label.
  2. In the Choose where to store your data section, do the following:
    1. Select a Location type.
    2. Choose a location where your bucket's data is permanently stored from the Location type drop-down menu.
      - If you select the dual-region location type, you can also choose to enable turbo replication by using the relevant checkbox.
    3. To set up cross-bucket replication, select Add cross-bucket replication via Storage Transfer Service and follow these steps:
      Set up cross-bucket replication
      
      In the Bucket menu, select a bucket.
      
      In the Replication settings section, click Configure to configure settings for the replication job.
      
      The Configure cross-bucket replication pane appears.
      
      To filter objects to replicate by object name prefix, enter a prefix that you want to include or exclude objects from, then click Add a prefix.
      
      To set a storage class for the replicated objects, select a storage class from the Storage class menu. If you skip this step, the replicated objects will use the destination bucket's storage class by default.
      
      Click Done.
  3. In the Choose how to store your data section, do the following:
    1. Select a default storage class for the bucket or Autoclass for automatic storage class management of your bucket's data.
    2. To enable hierarchical namespace, in the Optimize storage for data-intensive workloads section, select Enable hierarchical namespace on this bucket.
      Note: You cannot enable hierarchical namespace in existing buckets.
  4. In the Choose how to control access to objects section, select whether or not your bucket enforces public access prevention, and select an access control method for your bucket's objects.
    Note: You cannot change the Prevent public access setting if this setting is enforced at an organization policy.
  5. In the Choose how to protect object data section, do the following:
    - Select any of the options under Data protection that you want to set for your bucket.
      - To enable soft delete, click the Soft delete policy (For data recovery) checkbox, and specify the number of days you want to retain objects after deletion.
      - To set Object Versioning, click the Object versioning (For version control) checkbox, and specify the maximum number of versions per object and the number of days after which the noncurrent versions expire.
      - To enable the retention policy on objects and buckets, click the Retention (For compliance) checkbox, and then do the following:
        
        To enable Object Retention Lock, click the Enable object retention checkbox.
        
        To enable Bucket Lock, click the Set bucket retention policy checkbox, and choose a unit of time and a length of time for your retention period.
    - To choose how your object data will be encrypted, expand the Data encryption section (), and select a Data encryption method.
4. Click Create.

Back up a Ranger schema

Use SSH to connect to the Dataproc master node of the cluster with the Ranger schema. Run the commands in this section in the SSH terminal session running on the master node.
Set environment variables.
```
BUCKET_NAME=bucket name \
  MYSQL_PASSWORD=MySQL password
  SCHEMA_FILE=schema filename
```
Replace the following:
- MySQL password: You can open /etc/mysql/my.cnf on the cluster master node to copy the MySQL password.
- bucket name: The name of the Cloud Storage bucket to use to store the Ranger schema.
- schema filename: Specify a filename, without the .sql filename extension. The Ranger schema is saved to this file on the master node, then saved in bucket name in Cloud Storage .

Stop Hive services.

sudo systemctl stop hive-metastore.service
sudo systemctl stop hive-server2.service

Prevent changes to the Ranger schema tables.

mysql -u root -p${MYSQL_PASSWORD}
REVOKE ALL PRIVILEGES ON ranger.* from 'rangeradmin'@'localhost';
GRANT SELECT ON ranger.* TO 'rangeradmin'@'localhost';
FLUSH PRIVILEGES;
SHOW GRANTS FOR 'rangeradmin'@'localhost';
exit;

Save the Ranger schema to an .sql file.

mysqldump -u root -p${MYSQL_PASSWORD} ranger > ${SCHEMA_FILE}.sql

Reset Ranger privileges.

mysql -u root -p${MYSQL_PASSWORD}
REVOKE SELECT ON ranger.* from 'rangeradmin'@'localhost';
GRANT ALL PRIVILEGES ON ranger.* to 'rangeradmin'@'localhost';
FLUSH PRIVILEGES;
SHOW GRANTS FOR 'rangeradmin'@'localhost';
exit;

Restart Hive and Ranger services.

sudo systemctl start hive-metastore.service
  sudo systemctl start hive-server2.service
  sudo systemctl restart ranger-admin.service
  sudo systemctl restart ranger-usersync.service

Copy the Ranger schema to Cloud Storage.

gcloud storage cp ${SCHEMA_FILE}.sql gs://${BUCKET_NAME}

Restore a Ranger schema

Use SSH to connect to the Dataproc master node of the cluster where you will restore the cluster schema. Run the commands in this section in the SSH terminal session running on the master node.
Set environment variables.
```
BUCKET_NAME=bucket name \
  MYSQL_PASSWORD=MySQL password
  SCHEMA_FILE=schema filename
```
Replace the following:
- MySQL password: You can open /etc/mysql/my.cnf on the cluster master node to copy the MySQL password.
- bucket name: The name of the Cloud Storage bucket that contains the saved Ranger schema.
- schema filename: The name of the Ranger schema filename, without the .sql filename extension, saved in bucket name in Cloud Storage.