dba blogs: 2017

There are Three ways to configure Oracle Container database (CDB) with Pluggable databases (PDBs) for Network isolation.

they are

1) Using Connection Manager (CMAN) with Access Control rules. ( Oracle Recommended way )

2) using 12.2 new feature Access control layer for PDBs. ( 12.2 New feature )

3) One listener per PDB on a distinct port and have firewall white-list for each PDB. ( works in DBaaS in Oracle cloud. But not practical when there are many PDBS.)

1) CMAN :

Using CMAN is the recommended way. You have a one time configuration of a CMAN server which listens to user connections and forwards to the remote DB listener.

The remote DB listener registers their services when their DBs configure remote_listener parameter in the database.

The Access Control rules in the CMAN configuration file cman.ora works like a firewall whitelist where you configure ipaddress lists that are allowed to access each service. In 12c, since each PDB is a service, the rules can be used to network-isolate each PDB. This way, each PDB tennant is completely isolated from the neighboring PDB and cannot access it even if they know username password and connect string.

Cman lister will listen on a port witn a service_name "cman" registered. CMAN also registers all the PDBs to which connections could be forwarded. This service then forwards the connection to the other registered PDBS if the rule sets are accepted. All DBs that need connection forwarded to them, need to register the services by configuring the remote listeners (remote_listener parameter).

Below is a quick list of steps you need to do to configure a CMAN.

Step a) install CMAN. : you will have to install CMAN from Oracle client Software. Choose custom install and choose Connection manager and sql*net. You can install CMAN on the same server as CDB or on a remote server.

Step b) configure cman.ora in CMAN_HOME/network/admin directory.

Below is the example of configuring cman.ora

cman_test =

(configuration=

(address=(protocol=tcp)(host=list)(port=1999))

(parameter_list =

(aso_authentication_filter=off)

(connection_statistics=yes)

(log_directory=/home/oracle/logs)

(log_level=off)

(max_connections=256)

(idle_timeout=0)

(inbound_connect_timeout=0)

(session_timeout=0)

(outbound_connect_timeout=0)

(max_gateway_processes=16)

(min_gateway_processes=2)

(remote_admin=on)

(trace_directory=/home/oracle/logs)

(trace_level=admin)

(trace_timestamp=off)

(trace_filelen=1000)

(trace_fileno=1)

(max_cmctl_sessions=4)

(event_group=init_and_term,memory_ops)

)

(rule_list=

(rule=

(src=140.86.39.27)(dst=*)(srv=pdb1)(act=accept)

(action_list=(aut=off)(moct=0)(mct=0)(mit=0)(conn_stats=on))

)

(rule=(src=list)(dst=127.0.0.1)(srv=cmon)(act=accept))

(rule=(src=140.86.39.27)(dst=*)(srv=list)(act=accept))

(rule=(src=140.86.39.63)(dst=*)(srv=pdb2)(act=accept))

)

This service rule " (rule=(src=<cman_hostname>)(dst=127.0.0.1)(srv=cmon)(act=accept)" is a mandatory rule that will start a cman listener service CMAN on the given port "(address=(protocol=tcp)(host=<cnamHost>)(port=1999)) ". Without this line, you will get errors like

"(EVENT=CMAN.ORA contains no rule for local CMCTL connection)(Add (rule=(src=list)(dst=127.0.0.1)(srv=cmon)(act=accept)) in rule_list)"

Other rules like "(rule=(src=140.86.39.63)(dst=*)(srv=pdb2)(act=accept))" forwards connection requests from ipaddress 140.86.39.63 to pdb2 only, provided that service is registered.

Step c) start CMAN.

Using, CMCTL, connect to configuration profile in cman.ora. The alias in the above example is cman_test.

[oracle@list ~]$ cmctl

CMCTL> ADMINISTER cman_test

CMCTL:cman_test> .

Step d) Register remote PDBs or services

alter system set remote_listener='(ADDRESS = (PROTOCOL=TCP)(HOST=129.150.66.81)(PORT=1999))';

Note: if you DB listener is on 1521, then the PDBs get autoregistered in local and remote listener.

Step e) connect from client:

SQL> conn system/Saturn_02@//<cman_host>:1999/pdb2

Connected.

or configure tnsname.ora to point to cman host, cman port and service name.

Note, The clients may not have access to the PDBs directly and may not even know the ipaddress. However, as long a the DBs can access the cman host and port, the connection gets forwarded.

2) Database Service Firewall

This option is based new functionality of 12.2 database. It is called Database Service Firewall.

It is part of Oracle Access Control List. (ACL). Each policy is represented by an access control list (ACL) containing hosts that are allowed access to a specific database service. Local listeners and server processes validate all inbound client connections against the ACL.

Below are the steps to configure the DB for PDB isolation using Database service firewall.

Step a) You need a package DBMS_SFW_ACL_ADMIN package. This is installed by running as sysdba. This package is owned by the DBSFWUSER schema. The procedures in this package can be run only by the DBSFWUSER user.

SQL> conn / as sysdba

Connected.

-- Create user and package.

SQL> @$ORACLE_HOME/rdbms/admin/dbmsaclsrv.sql

Step B)

Configure the listener.ora and set LOCAL_REGISTRATION_ADDRESS_LISTENER and firewall=on. Below is the sample listener.ora with modification in red.

LISTENER =

(DESCRIPTION_LIST =

(DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = CDB4.compute-dbuser19.oraclecloud.internal)(PORT = 1521) (firewall=on))

)

VALID_NODE_CHECKING_REGISTRATION_LISTENER=ON

SSL_VERSION = 1.0

LOCAL_REGISTRATION_ADDRESS_LISTENER= (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))

Step C) Start the listener.

[oracle@CDB4 admin]$ lsnrctl start

LSNRCTL for Linux: Version 12.2.0.1.0 - Production on 10-MAR-2017 22:35:08

Starting /u01/app/oracle/product/12.2.0/dbhome_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 12.2.0.1.0 - Production

System parameter file is /u01/app/oracle/product/12.2.0/dbhome_1/network/admin/listener.ora

Log messages written to /u01/app/oracle/diag/tnslsnr/CDB4/listener/alert/log.xml

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CDB4.compute-dbuser19.oraclecloud.internal)(PORT=1521)(FIREWALL=ON)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=CDB4.compute-dbuser19.oraclecloud.internal)(PORT=1521)(firewall=on)))

STATUS of the LISTENER

------------------------

Alias LISTENER

Version TNSLSNR for Linux: Version 12.2.0.1.0 - Production

Start Date 10-MAR-2017 22:35:08

Uptime 0 days 0 hr. 0 min. 0 sec

Trace Level off

Security ON: Local OS Authentication

SNMP OFF

Listener Parameter File /u01/app/oracle/product/12.2.0/dbhome_1/network/admin/listener.ora

Listener Log File /u01/app/oracle/diag/tnslsnr/CDB4/listener/alert/log.xml

Listening Endpoints Summary...

(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=CDB4.compute-dbuser19.oraclecloud.internal)(PORT=1521)(FIREWALL=ON)))

The listener supports no services

The command completed successfully

[oracle@CDB4 admin]$ sqlplus / as sysdba

SQL*Plus: Release 12.2.0.1.0 Production on Fri Mar 10 22:36:55 2017

Step D) Now setup the local_listener to point to the listener.

SQL> alter system set local_listener='(ADDRESS = (PROTOCOL=TCP)(HOST=localhost)(PORT=1521))';

System altered.

SQL> alter system register;

System altered.

SQL> show pdbs

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

2 PDB$SEED READ ONLY NO

3 CDB4PDB1 READ WRITE NO

6 MYLOCAL READ WRITE NO

Step e) Note that you will get errors if you do not include the DBSFWUSER.

Add the ACL service ipaddress for the perticulat PDB and the IP address from which to allow connections.

SQL> execute dbms_sfw_acl_admin.ip_add_pdb_ace('CDB4PDB1','140.86.12.219');

BEGIN dbms_sfw_acl_admin.ip_add_pdb_ace('CDB4PDB1','140.86.12.219'); END;

ERROR at line 1:

ORA-06550: line 1, column 7:

PLS-00201: identifier 'DBMS_SFW_ACL_ADMIN.IP_ADD_PDB_ACE' must be declared

ORA-06550: line 1, column 7:

PL/SQL: Statement ignored

SQL> exec DBSFWUSER.DBMS_SFW_ACL_ADMIn.ip_add_pdb_ace('CDB4PDB1','140.86.12.219');