Enable PostgreSQL 13 on CentOS 8/Stream 9 Using DNF Modules

Desired Outcome

Activate the PostgreSQL 13 module stream on a CentOS 8 or CentOS Stream 9 system, install the corresponding server and client packages, initialize a new database cluster, start the service, and confirm that the running instance is indeed PostgreSQL 13.

Prerequisites

• Root or sudo access on the target machine.
• Internet connectivity to reach CentOS repositories.
• For CentOS 8, ensure the AppStream repository is enabled; for CentOS Stream 9 the same applies.
• If a PostgreSQL cluster already exists, back it up before proceeding, as re‑initialization will erase data.

Procedure

1. Verify Current Module Status

   Run the following to see which PostgreSQL streams are available and which are enabled:

   sudo dnf module list postgresql
   

   Look for a line similar to postgresql:13 stream enabled after enabling.

2. Enable the PostgreSQL 13 Stream

   Activate the desired stream. This command will resolve dependencies and remove conflicting packages from other streams.

   sudo dnf module enable postgresql:13
   

   Check the list again to confirm:

   sudo dnf module status postgresql
   

3. Install the Server Package

   With the stream enabled, install the server (and client libraries) that match the stream:

   sudo dnf install -y postgresql-server
   

   After installation, dnf list installed | grep postgresql should show postgresql-13.x and postgresql-libs-13.x.

4. Initialize the Database Cluster

   PostgreSQL requires an initial cluster before it can run. The postgresql-setup script handles this in CentOS.

   sudo postgresql-setup --initdb
   

   On CentOS 9 the syntax is the same. This creates /var/lib/pgsql/13/data and sets ownership to the postgres user.

5. Start and Enable the Service

   Enable the service to start on boot and start it immediately:

   sudo systemctl enable --now postgresql
   

   Verify the service status:

   sudo systemctl status postgresql
   

6. Confirm PostgreSQL Version

   Switch to the postgres user and query the server version:

   sudo -i -u postgres psql --version
   

   Alternatively, connect to the server and run SELECT version();:

   sudo -i -u postgres psql -c "SELECT version();"
   

Verification Checklist

Check	Command	Expected Result
Module Stream	sudo dnf module status postgresql	13 stream enabled
Installed Packages	sudo dnf list installed | grep postgresql	postgresql-13.x listed
Service Active	sudo systemctl is-active postgresql	active (running)
Server Version	sudo -i -u postgres psql --version	psql 13.x
Cluster Data Directory	ls -ld /var/lib/pgsql/13/data	exists, owned by postgres

Recovery / Rollback

• If the module enabled step removed packages you need, you can disable the stream and enable a different one:

sudo dnf module disable postgresql:13
sudo dnf module enable postgresql:12

• To revert an initialization that erased data, restore from a recent backup before running postgresql-setup --initdb again.

Limitations & Notes

• CentOS 8 reached end‑of‑life in 2021. For production workloads, use CentOS Stream 9 or another supported RHEL‑derived distribution.
• Enabling a module stream can downgrade or remove packages from other streams. Always review the list of affected packages with dnf module status before proceeding.
• The postgresql-setup --initdb command will overwrite an existing cluster. Back up /var/lib/pgsql/13/data if it contains important data.
• Firewall rules and SELinux contexts are not modified by this guide. Ensure firewalld allows the PostgreSQL port (default 5432) and that SELinux is permissive for PostgreSQL if using enforcing mode.

Practical Check

After completing the steps, a quick test is to create a temporary table:

sudo -i -u postgres psql -c "CREATE TABLE test(id INT);"

If the command succeeds, the database is fully operational. Drop the table afterward:

sudo -i -u postgres psql -c "DROP TABLE test;"

Summary

By enabling the PostgreSQL 13 module stream, installing the server package, initializing the cluster, and verifying the service, you have a clean, version‑specific PostgreSQL installation on CentOS 8 or Stream 9. The module system keeps your system tidy, automatically handling dependencies and avoiding conflicts with other PostgreSQL streams.