Hardened PostgreSQL 17 on CentOS Stream 9

Charges for this image cover the security hardening, optimization, and pre-integration work Hanwei performs on top of the upstream PostgreSQL 17 and CentOS Stream 9 projects. PostgreSQL 17 is installed from the PostgreSQL Global Development Group repository, the cluster is initialized and the service is enabled, so the database is listening when the instance finishes booting. This version replaces the earlier PostgreSQL 15 image. The operating system underneath carries the same hardened and tuned baseline used across this catalogue.

What Hanwei Adds to Upstream PostgreSQL 17

• Cluster installed and initialized at build time: packages come from the PostgreSQL Global Development Group repository, the cluster lives under /var/lib/pgsql/17/data and the postgresql-17 service is enabled.
• Transparent huge pages disabled at boot: a oneshot unit sets them to never before the database starts, following the vendor's guidance. This is not the distribution default, where the tuned virtual-guest profile leaves them enabled.
• contrib extensions present: pg_stat_statements, pgcrypto and the other bundled modules can be created without adding packages.
• Tuning baseline applied identically across the catalogue: the file descriptor limit goes from 1024 to 65536 and the memory-map ceiling from 65530 to 262144; the device receive backlog goes from 1000 to 16384 and the TCP SYN backlog from 128 to 8192, so bursts queue instead of being dropped; socket buffer maxima reach 16 MB for larger autotuned windows; connections keep their congestion window across idle periods; and the journal is capped at 500 MB. The profile raises ceilings only and does not alter protocol semantics or application behaviour.
• Applied hardening beyond the distribution default: SSH is limited to a vetted cipher, key exchange and MAC list, X11 forwarding is off, the login grace period is shortened and verbose authentication logging is on; auditd runs a base rule set for privileged command execution; the kernel drops ICMP redirects on IPv4 and IPv6, logs martian packets, filters reverse paths in loose mode, restricts dmesg, disables setuid core dumps and turns off sysrq.
• AWS operational integration: the SSM Agent is installed and enabled for Session Manager and Patch Manager without an inbound SSH rule; chrony points at the Amazon Time Sync Service; and the root filesystem extends at boot when the volume exceeds the image default.
• Patch level set at the build date: packages come from official upstream repositories at the newest level published when the image was built.
• Repeatable build and EC2 validation: each version comes from the same build process and is launched and exercised on EC2 before release.

Access and Security Posture

• SELinux runs in enforcing mode and auditd records activity against a base rule set.
• Sign in as 'ec2-user' with the key pair selected at launch, then use 'sudo su -' for a root shell. Session Manager is available as an alternative that needs no inbound port.
• Direct root login over SSH is disabled and password authentication is not accepted.
• No authorized keys and no SSH private keys are embedded in the image.

Operational Impact on EC2

• Launch-to-usable-database time is reduced to a single boot cycle.
• Every instance starts from an identical configuration, removing drift between development, staging and production hosts.
• Network services need no per-host limit or backlog adjustment before handling load.
• Clock accuracy comes from the Amazon Time Sync Service, which matters for log correlation and request signing.
• Post-launch patching effort is lower because the package set is current at release.

Where This Image Fits

• Application backends that need a PostgreSQL endpoint on an instance the team controls.
• Development and test environments recreated frequently from an identical configuration.
• Analytical and reporting databases where the raised descriptor and memory-map ceilings matter under many concurrent connections.
• Migration staging, where a target cluster must be available quickly for dump and restore rehearsals.

About PostgreSQL 17 and CentOS Stream 9

PostgreSQL is an object-relational database known for standards compliance, transactional DDL and an extension mechanism covering geospatial data, full-text search, time series and vector similarity. Version 17 adds incremental backup, a rewritten vacuum memory manager, faster bulk loading through COPY and better planning for correlated subqueries. The 17 series is supported by the PostgreSQL project into 2029.

CentOS Stream 9 is a Linux distribution that tracks the development stream of Red Hat Enterprise Linux 9. Packages land in CentOS Stream before they appear in a RHEL minor release, so it stays close to the RHEL package set and toolchain while remaining freely redistributable. It uses dnf, systemd and SELinux, which makes it a predictable base for server workloads that need RHEL compatibility.