Hardened Python 3.10 on CentOS Stream 9

Charges for this image cover the security hardening, optimization, and pre-integration work Hanwei performs on top of the upstream Python 3.10 and CentOS Stream 9 projects. Python 3.10 is built from source during the image build and installed alongside the distribution interpreter rather than over it, so python3.10 and its pip are on PATH while dnf and the system python3 keep working. The operating system underneath is configured to a fixed hardened and tuned baseline and validated on EC2 before publication.

What Hanwei Adds to Upstream Python 3.10

• Interpreter built from source and installed side by side: CentOS Stream 9 ships Python 3.9, so 3.10 is compiled at build time and installed with make altinstall. The distribution interpreter at /usr/bin/python3 is left untouched, which is what keeps dnf and the rest of the system tooling functional.
• Optional modules compiled in: the build enables ssl, sqlite3, zlib, bz2, lzma, ctypes and readline, so virtual environments, package installation over TLS and local database access work without recompiling the interpreter.
• Build dependencies preinstalled: gcc, pkgconf and the OpenSSL development headers remain on the image, so packages with C extensions build from source when no wheel is available.
• 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-first-run 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 hosts pinned to Python 3.10 for library or framework compatibility.
• Build and CI hosts that must test against 3.10 specifically rather than the distribution version.
• Data processing instances where C extension packages have to compile locally.
• Migration staging for codebases moving off older interpreters.

About Python 3.10 and CentOS Stream 9

Python 3.10 introduced structural pattern matching, parenthesised context managers, precise error locations in tracebacks and the union type operator. It remains a common pin for applications whose dependency set is validated against this series rather than a later one.

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.