How to Install Oracle AI Database 26ai Free on Oracle Linux

Oracle AI Database 26ai Free is the free edition of Oracle's database for developers and learners. It has the features a developer uses, including SQL, PL/SQL, JSON, graphs, AI Vector Search, JavaScript, and Oracle Text, with limits on resources: 2 CPU threads, 2 GB of memory, and 12 GB of user data. Code you write on it runs unchanged on the Enterprise and Standard Editions and on Oracle's cloud databases.

This guide installs it natively on Oracle Linux 8 or 9 from Oracle's RPM packages, so it runs as a systemd service that starts at boot. Red Hat Enterprise Linux 8 and 9 work the same way, with one extra step noted below. You will also see how the container database is organized, how clients connect through the listener, and how to start, stop, and troubleshoot the database.

Code for This Guide

The SQL examples are files 02 and 03 in the examples/install folder of the Oracle Database 26ai code repository on GitHub, each with its output.

They come from Oracle Database 26ai SQL and PL/SQL Book.

Requirements

The database ships as RPM packages for Linux x86-64 and Linux on Arm (aarch64).

Three rules catch people out:

• One Free database per host. A second Free database on the same server, virtual machine, or container refuses to start with ORA-00442. Remove any older XE or Free installation first.
• /opt/oracle must be a real directory, not a symbolic link. If /opt is small, mount a separate file system at /opt/oracle.
• The host name must resolve to an address other than the loopback address, or the configuration script fails.

Step 1: Prepare the Server

As your administrator account, update the system and check that the host name resolves.

Example:

sudo dnf -y update
hostname -f
getent hosts "$(hostname -f)"

If the last command prints nothing, or only 127.0.0.1, add a line with the server's real address and name to /etc/hosts, for example 192.168.1.50 dbsrv.example.com dbsrv, and check again.

Step 2: Install the Preinstallation RPM

The preinstallation package installs the libraries the database needs, creates the oracle user and the oinstall and dba groups, and sets kernel parameters and resource limits. On Oracle Linux it is in the standard repositories.

Example:

sudo dnf -y install oracle-ai-database-preinstall-26ai

On Red Hat Enterprise Linux, download the latest oracle-ai-database-preinstall-26ai file from Oracle's yum server (for release 9, https://yum.oracle.com/repo/OracleLinux/OL9/appstream/x86_64/; for release 8, the OL8 folder and the el8 file) and install the file with dnf -y install ./file-name.rpm.

The kernel settings it changed are logged in /var/log/oracle-ai-database-preinstall-26ai/results/orakernel.log and kept in /etc/sysctl.d/97-oracle-database-sysctl.conf. The oracle user has no password, which is how it should stay; reach it with sudo -iu oracle.

Step 3: Install the Database RPM

Download the RPM for your release and processor from Oracle's Oracle AI Database Free download page. At the time of writing, the release is 23.26.3, and the files are named like this:

Each is about 1.5 GB. You can download it on the server itself; for Oracle Linux 9 on x86-64:

Example:

cd /tmp
BASE=https://download.oracle.com/otn-pub/otn_software/db-free
RPM=oracle-ai-database-free-26ai-23.26.3-1.el9.x86_64.rpm
curl -LO "$BASE/$RPM"
sudo dnf -y install "./$RPM"

If a newer release is out, copy its file name from the download page. The package installs the software into the Oracle home, /opt/oracle/product/26ai/dbhomeFree, but does not create a database yet.

Step 4: Create the Database

The configuration script creates the database and the listener. Its defaults are listener port 1521, character set AL32UTF8, and database files under /opt/oracle/oradata. To change them, copy and edit /etc/sysconfig/oracle-free-26ai.conf first.

Example:

sudo /etc/init.d/oracle-free-26ai configure

The script asks twice for one password, which becomes the password of SYS, SYSTEM, and PDBADMIN. Use at least eight characters with uppercase and lowercase letters and a digit. Creating the database takes several minutes. If it fails, read FREE.log in /opt/oracle/cfgtoollogs/dbca/FREE.

Step 5: Start the Database at Boot

The database is running now, but it will not start after a reboot until you enable its service.

Example:

sudo systemctl daemon-reload
sudo systemctl enable oracle-free-26ai
sudo /etc/init.d/oracle-free-26ai status

The status command reports the listener and the FREE database; both should be RUNNING. From now on, systemd starts them at boot and shuts the database down cleanly when the server stops.

Step 6: Set Up the oracle User's Environment

SQL*Plus, lsnrctl, and the other tools need ORACLE_HOME, ORACLE_SID, and PATH. Oracle's oraenv script sets them; add it to the oracle user's profile so every shell has them.

Example:

sudo -iu oracle
cat >> ~/.bash_profile <<'EOF'

# Oracle AI Database 26ai Free
export ORACLE_SID=FREE
export ORAENV_ASK=NO
export ORACLE_HOME=/opt/oracle/product/26ai/dbhomeFree
. /opt/oracle/product/26ai/dbhomeFree/bin/oraenv > /dev/null
EOF
. ~/.bash_profile
which sqlplus

ORAENV_ASK=NO stops oraenv from prompting, and the last command prints /opt/oracle/product/26ai/dbhomeFree/bin/sqlplus.

Step 7: Connect and Look Around

The oracle user can connect as SYS without a password. This operating-system authentication works even when the listener is down, which makes it the tool for maintenance.

Example:

sqlplus / as sysdba

The Container Database and Its PDBs

An Oracle database is a container database (CDB). Its root, CDB$ROOT, holds Oracle's own metadata and is administered by SYS. PDB$SEED is a read-only template for new databases. The pluggable databases (PDBs) hold the users, schemas, and data of applications; each looks like a database of its own to the applications that connect to it, and can be unplugged, moved, and cloned. Oracle AI Database Free comes with one PDB, FREEPDB1, which is where your own schemas belong.

SHOW PDBS lists the PDBs, and v$containers lists every container, root included.

Example:

alter session set container = cdb$root;           -- the root of the container database
show pdbs

select con_id, name, open_mode from v$containers order by con_id;

Output:

Session altered.

   CON_ID CON_NAME    OPEN MODE     RESTRICTED
_________ ___________ _____________ _____________
        2 PDB$SEED    READ ONLY     NO
        3 FREEPDB1    READ WRITE    NO

   CON_ID NAME        OPEN_MODE
_________ ___________ _____________
        1 CDB$ROOT    READ WRITE
        2 PDB$SEED    READ ONLY
        3 FREEPDB1    READ WRITE

To work inside the PDB as SYS, move the session there with alter session set container = FREEPDB1;.

Services and the Listener

Clients do not connect to database files but to a service, through the listener, a process that accepts connections on port 1521 and hands them to the database. Each container has a service of its own name: free for the root and freepdb1 for the PDB. Applications and developers connect to the PDB's service; only administrators connect to the root.

Example:

alter session set container = cdb$root;
select name, con_name from v$active_services
where  name not like 'SYS$%'
order  by 1;

Output:

Session altered.

NAME        CON_NAME
___________ ___________
free        CDB$ROOT
freeXDB     CDB$ROOT
freepdb1    FREEPDB1

If the server has a domain, the service names include it, for example freepdb1.example.com. lsnrctl status shows the listener and the services it knows; the list at the end should include FREE and freepdb1.

Example:

lsnrctl status

Through the listener, connect to the PDB with SQLcl or SQL*Plus using host, port, and service.

Example:

sql system@localhost:1521/FREEPDB1

Connect from Another Computer

Port 1521 is closed by firewalld. The safest way to reach the database from your desktop is an SSH tunnel, which forwards port 1521 on your computer to the server through the SSH connection you already have.

Example:

ssh -L 1521:localhost:1521 you@dbsrv.example.com

While the tunnel is open, localhost:1521/FREEPDB1 on your desktop reaches the server's database. Open the port only on a network you trust.

Example (open the port instead):

sudo firewall-cmd --permanent --add-port=1521/tcp
sudo firewall-cmd --reload

Start and Stop the Database

The service is the normal way to start and stop it, and systemd does it for you at boot and shutdown.

Example:

sudo systemctl stop oracle-free-26ai
sudo systemctl start oracle-free-26ai
sudo /etc/init.d/oracle-free-26ai status

An administrator can also do it in SQL*Plus, connected as SYSDBA to the root.

Example:

shutdown immediate                         -- close the database: sessions are disconnected
startup                                    -- start the instance and open the database
alter pluggable database freepdb1 close;   -- close one PDB
alter pluggable database freepdb1 open;
alter pluggable database freepdb1 save state;   -- reopen it automatically after a restart

SHUTDOWN IMMEDIATE rolls back open transactions and closes the database cleanly. SHUTDOWN ABORT stops it at once, and the next startup recovers it.

Where Things Live

Troubleshooting

Remove the Database

sudo /etc/init.d/oracle-free-26ai delete deletes the database, its files, and the listener configuration, and sudo dnf remove oracle-ai-database-free-26ai removes the software. This deletes all data, so export what you need first.

Related Guides

• How to Install Oracle APEX 26.1 on Oracle Linux, which adds Java, ORDS, and APEX on top of this database
• Install Oracle Database on macOS Apple Silicon (ARM64) Using Docker

Conclusion

To install Oracle AI Database 26ai Free on Oracle Linux, install oracle-ai-database-preinstall-26ai and the database RPM, run /etc/init.d/oracle-free-26ai configure to create the FREE container database with FREEPDB1, and enable the oracle-free-26ai service. Set the oracle user's environment with oraenv, connect with sqlplus / as sysdba for maintenance, and connect applications through the listener to localhost:1521/FREEPDB1.