Recently we wanted to remove license for one of our clusters, and we used the following approach to remove the license from the cluster. We are on CDH 5.11 which is very old and gone out of support.

For planning, first step it to evaluate the licensed feature currently in use. If you are actively using any of such features, it might affect the functionality and cause major issues if not planned properly. on the top of my head, the key features like below needs to checked

* Rolling upgrade of CDH,
* Manage Key Trustee and Cloudera Navigator,
* Configuration versioning and history,
* Restoring a configuration using the API,
* LDAP authentication for Cloudera Manager
* SAML authentication
* Data encryption with KMS
* Cloudera Manager user roles
* Alert by SNMP
* Automated backup and disaster recovery
* File browsing, searching, and disk quota management
* HBase, MapReduce, Impala, and YARN usage reports
* Metadata management and augmentation
* Ingest policies
* Auditing and Lineage

For a complete list, I suggest working with Cloudera Support or documentation to get complete information.

Coming to technical steps for removing license, converting from Enterprise to Express edition. Since Cloudera Manager 5.11 (less the 5.13) does not have an option to remove license from cloudera manager UI, we have to use the database approach, ie, we would be deleting the license key from backend database of the Cloudera manager.

First, Log in to Cloudera Manager and stop the Cloudera Management Services. (Host Monitor, Event server, Alert Publisher, etc)

Next from the Cloudera Manager server shell, Stop Cloudera Manager.

service cloudera-scm-server stop

We can check the the Cloudera Manager database instance name and credentials from the db.properties file. Default location of the file is /etc/cloudera-scm-server/db.properties

Use the values of below parameters for connecting to database.

com.cloudera.cmf.db.type=$DBTYPE   
com.cloudera.cmf.db.host=$DBHOST:$DBPORT
com.cloudera.cmf.db.name=$DBNAME
com.cloudera.cmf.db.user=$DBUSER
com.cloudera.cmf.db.password=$DBPASS

If DBPORT is empty, use default port 3306 for mysql, I am covering steps for Mysql and Postgres, but steps would be fairly same for other databases like oracle and MsSql as well.

Start with backing up the database

\\For MySQL:# 

mysqldump -h $DBHOST -P $DBPORT -u $DBUSER -p $DBNAME > /root/backup.`date +%Y-%m-%d:%H:%M`. sql

For Postgres:# 

pg_dump -h $DBHOST -p $DBPORT -U $DBUSER -W $DBNAME > /root/backup.`date +%Y-%m-%d:%H:%M`.sql

Then, login to databases

For MySQL:#

mysql -h $DBHOST -P $DBPORT -u $DBUSER -p $DBNAME

For Postgres:# 

psql -h $DBHOST -p $DBPORT -U $DBUSER -W $DBNAME

Type the $DBPASS when requested. Update the record to remove the license key.

update CONFIGS set VALUE = '' where ATTR = 'license_key';

Validate the changes

select CONFIG_ID, ATTR, VALUE from CONFIGS where ATTR = 'license_key';
+-----------+-------------+-------+
-- | CONFIG_ID | ATTR | VALUE |
-- +-----------+-------------+-------+| 79 | license_key | |+-----------+-------------+-------+
1 row in set (0.00 sec)8.

Quit the shell

For MySQL:mysql> quit
For Postgres:scm> \q

Once completed, restart the Cloudera manager server.

service cloudera-scm-server start

Once Cloudera manager is started, login to Cloudera Manager and start the Cloudera Management Services. Finally, just restart the services and make sure, everything is working fine.

When we check the license page now, you would notice that Cloudera Express is in use and tab for BDR(backup) is gone now.