Traditional packaging requires users to maintain a reference database, but often this is expensive and cumbersome to manage. Using an Oracle Ephemeral Database eliminates the need to manage an additional database on the pipeline. A default installation requires the use a Reference Database. You simply configure Liquibase to When using Oracle PDBs, configuration can be setup to have Liquibase create a temporary copy of a database in the pipeline to be used in place of the Reference Database. Once the copy is made you will ensure that all of your changes work on the copy, implement them on your original database’s changelog, and then destroy the database copy. Follow this guide to learn how to implement this workflow.

Pre-requisites

• Use Liquibase Enterprise 8.6 and higher

• Based on Oracle multi-tenant PDB technology

• Ephemeral database connection requires a user on ORCLCDB with SYSOPER privileges and the ability to create pluggable databases

Limitations

• Ephemeral database feature works ONLY for PDB databases

• Ephemeral database feature works ONLY for Oracle 19c and 21c

• Ephemeral database feature does not work for Oracle RDS

• You cannot place the temporary copied database in a pipeline or run a status on it because technically it does not exist in the pipeline.

Usage

<graphics and info regarding:

During packager operation it will create a pluggable PDB copy, package all the changes on it and drop the PDB copy after it, if final deploy is not skipped - it will deploy newly packaged changes on desired db def (which is DEV in most of the examples)>

Backup and Restore Package Methods

In order to implement Ephemeral Database, the databaseBackupRestoreMethod packageMethod on the deployPackager.properties needs to be configured.

Two new package methods are supported. You can use an internal or external container depending on your needs. If your internal container is secured and permissions do not allow you to make changes within it, the external package method is recommended.

See: Use the Required deployPackager.properties File

BackupRestoreOracleEphemeralInternalPdb

Create ORCLCDB SYSOPER User

You must create a new user on oracle CDB with the following privileges to create an ephemeral copy.

# Should be created on ORCLCDB
CREATE USER c##liquibase_ephemeral_user IDENTIFIED BY password;
GRANT CREATE SESSION TO c##liquibase_ephemeral_user CONTAINER=all;
GRANT CREATE PLUGGABLE DATABASE TO c##liquibase_ephemeral_user CONTAINER=all;
GRANT SYSOPER TO c##liquibase_ephemeral_user CONTAINER=all;

BackupRestoreOracleEphemeralExternalPdb

BackupRestoreOracleEphemeralExternalPdb differs from BackupRestoreOracleEphemeralInternalPdb, that it makes a copy between two different DB instances, so in all info below we are going to have database A and B, so we would like to make an ephemeral copy of the A’s database PDB to database B. To be able to use BackupRestoreOracleEphemeralExternalPdb as databaseBackupRestoreMethod our customer would need to prepare an additional set up for us.

Create ORCLCDB SYSOPER User

On the database A we will to create a new user on oracle CDB with the following privileges to be able to create an ephemeral copy

-- connect as SYSDBA to a FIRST DB to create common user
CREATE USER c##liquibase_ephemeral_user_a IDENTIFIED BY password;
GRANT CREATE SESSION TO c##liquibase_ephemeral_user_a CONTAINER=all;
GRANT CREATE PLUGGABLE DATABASE TO c##liquibase_ephemeral_user_a CONTAINER=all;
GRANT SYSOPER TO c##liquibase_ephemeral_user_a CONTAINER=all;

On the database B we will to create a new user on oracle CDB with the following privileges to be able to create an ephemeral copy and additionally create a link with database A

-- connect as SYSDBA to a SECOND DB to create common user
CREATE USER c##liquibase_ephemeral_user_b IDENTIFIED BY password;
GRANT CREATE SESSION TO c##liquibase_ephemeral_user_b CONTAINER=all;
GRANT CREATE PLUGGABLE DATABASE TO c##liquibase_ephemeral_user_b CONTAINER=all;
GRANT SYSOPER TO c##liquibase_ephemeral_user_b CONTAINER=all;

--- you need to know hostname, port and service name of DB2 database instance
--- you need to know credetials for database user which has enough priviliges 
---     to perform copy operation 
CREATE PUBLIC DATABASE LINK liquibase_db_link
    CONNECT TO c##liquibase_ephemeral_user_a IDENTIFIED BY password
    USING '(DESCRIPTION=
            (ADDRESS=(PROTOCOL=TCP)(HOST=172.18.0.2)(PORT=1521))
            (CONNECT_DATA=(SERVICE_NAME=ORCLCDB))
        )';

Also there is a possibility to use TNS name during link creation, e.g.

CREATE DATABASE LINK liquibase_db_link
 CONNECT TO c##liquibase_ephemeral_user_a IDENTIFIED BY password
 USING TNS_NAME;

To check if database link has been created correctly please run query below, if you don’t get errors - database link is correct.

SELECT * FROM dual@liquibase_db_link;

Associated deployPackager.properties

These are packaging properties available specifically for the ephemeral database packaging method.

See: Use the Required deployPackager.properties File

Changes to the Project Repository and datical.project

Follow these steps to implement the ephemeral database configuration for your workflow.

Create an Ephemeral dbDef

An ephemeral dbDef must be created in the datical.project file to instruct Liquibase which database should be cloned for the ephemeral copy and to set the connection string information. Because this database is transient by definition and only exists during the Deploy Packager operation, it is not eligible on a Liquibase pipeline to have Status run against it.

Methods for creating the Ephemeral dbDef

In order to create a dbDef without including the dbDef on an existing pipeline Liquibase recommends using ONE of the following methods:

1. Create the dbDef using the Liquibase Enterprise GUI and then delete the dbDef from the pipeline.

2. Include the ephemeral dbDef on the Project Creation Script but do not include the dbDef on any pipelines.

3. Manually copy the dbDef from an existing dbDef in the pipeline.

Follow the instructions below based on the desired method.

Method 1: Create the dbDef with the Liquibase Enterprise GUI

1. Create the dbDef using instructions from Creating a Liquibase Enterprise project Using the Liquibase Enterprise GUI

2. Ensure the Name of the database is <dbDef_to_be_cloned>_EPHEMERAL. This can be DEV, QA, STAGE, or PROD.

   

3. Enter your Connection Settings.

   1. If you are using a TNSNAMES/LDAP connection, see the section below Using TNSNAMES/LDAP with Oracle Ephemeral Database.

   2. If you are using a BASIC connection Service Name should be ORCLCDB or the name of the container that should house the ephemeral copy. (See Backup and Restore Package Methods section before for more information.)

      1. You will need to enter your container name in the Hostname text box. This entry will depend on if you are using an internal or external backup and restore method. (See Backup and Restore Package Methods section before for more information.)
         

      2. The username and password should be the ORCLCDB user created in step 1. Create ORCLCDB SYSOPER User above.

         

4. Contexts and Labels

   1. Contexts should be left blank or set to the same context as the dbDef to be cloned

   2. Labels should generally be set

      1. To the name of the pipeline that houses the dbDef to be cloned

      2. Or use the same pattern that is in use for the dbDef to be cloned

5. After creating the dbDef, remove the Step from the Pipeline by selecting Remove Step

   

6. Do not select the box to delete the Deployment Step from the Deployment Plan

   

Method 2: Create the dbDef with the Project Creation Script

1. Create the project using the instructions from Creating a Liquibase Enterprise Using the Project Creation Script (project_creator.groovy)

2. Include the ephemeral database on the ProjectNameOracle.dbdefs.tsv.txt. Use name <dbDef_to_be_cloned>_EPHEMERAL

3. Do not reference the ephemeral database as part of any pipeline on ProjectNameOracle.pipelines.tsv.txt

Method 3: Manually create the dbDef by copying from existing dbDef in datical.project

If you are manually copying the dbDef in the datical.project file from the dbDef to be cloned

1. If the password is present in the file, please note this value is Base64 encoded. If modifying this value, the new value will also need to be Base64 encoded.

2. Clear out the dbDefsId for the new _EPHEMERAL dbDef.

3. Do a Test Connection to the DMC Database (under Settings → Configure DMC DB → Test Connection) or perform a Status operation on the project in order to populate the dbDefsId for the new ephemeral dbDef.

   

Using TNSNAMES/LDAP with Oracle Ephemeral Database

Learn more about traditional LDAP connections here: LDAP Connection to an Oracle Database

If a customer uses TNS names in dbDef, then customer should prepare a TNS name with _eph postfix him self for the ephemeral copy which we are going to create, as in most cases we are not able to modify TNS files or they can be even stored on remote servers (e.g. OID). So if customer’s dbDefs look like that

<dbDefs xsi:type="dbproject:OracleDbDef" name="DEV" hostname="localhost" driver="oracle.jdbc.OracleDriver" tnsName="dev" />
<dbDefs xsi:type="dbproject:OracleDbDef" name="DEV_EPHEMERAL" driver="oracle.jdbc.OracleDriver" tnsName="admin_sysoper" />

then customer should also add dev_eph entry in TNS config pointing to a PDB which we are going to create. To determine service name or SID for the PDB which this TNS will point to, use the next logic:

1. If you provided value for oracleEphemeralCopyName , then it will be it

2. If you didn’t provide value for oracleEphemeralCopyName, but provided it for oracleEphemeralSourceName - it will be oracleEphemeralCopyName value + _eph postfix, e.g. if oracleEphemeralCopyName is bucket_01, then your value will be bucket_01_eph

3. If you didn’t provide any of these values, just add _eph postfix to your source PDB name, e.g if your source PDB name is bucket_01, then your value will be bucket_01_eph

This is tnsnames.ora file example that contains dev alias for DEV DbDef, dev_eph alias which customer needs to create, and admin_sysoper alias for DEV_EPHEMERAL DbDef:

dev =
(DESCRIPTION =
  (ADDRESS =
     (PROTOCOL = TCP)
     (HOST = 172.17.0.3)
     (PORT = 1521)
  )
  (CONNECT_DATA =
     (SERVER = DEDICATED)
     (SERVICE_NAME = bucket_01)
  )
)


dev_eph =
(DESCRIPTION =
  (ADDRESS =
     (PROTOCOL = TCP)
     (HOST = 172.17.0.3)
     (PORT = 1521)
  )
  (CONNECT_DATA =
     (SERVER = DEDICATED)
     (SID = bucket_01_eph)
  )
)

admin_sysoper =
(DESCRIPTION =
  (ADDRESS =
     (PROTOCOL = TCP)
     (HOST = 172.17.0.3)
     (PORT = 1521)
  )
  (CONNECT_DATA =
     (SERVER = DEDICATED)
     (SID = ORCLCDB)
  )
)

Potential grants issues

If oracleEphemeralSourceName packager property is not specified we try to get PDB name from 2 tables on the DB (v$pdbs and dba_data_files), if customer already gave the user required grants according to Multi-Schema Projects - Oracle Roles and Permissions , everything should work because both GRANT SELECT ANY DICTIONARY TO DATICAL_ROLE; and GRANT IMP_FULL_DATABASE TO DATICAL_PACKAGER_ROLE; already give us enough permission to query the tables, but if customer hasn’t given such permission to us and want to use the ephemeral databaseBackupRestoreMethod - permissions to query v$pdbs and dba_data_files should be provided.

Using Oracle Managed Files (OMF) with Oracle Ephemeral Database

If using OMF with BackupRestoreOracleEphemeralExternalPdb then OMF mode should be the same on both instances of the Oracle database.