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Introduction:
Red Hat Enterprise Linux (RHEL) has long been the cornerstone of enterprise IT infrastructure, powering mission-critical workloads across traditional data centers and hybrid cloud environments. With the introduction of RHEL 10, organizations face a pivotal decision: continue with the battle-tested stability of RHEL 9 or embrace a future-ready platform built for container-1ative workflows, AI-assisted administration, and GitOps-driven automation. This article dissects the technical evolution between these two releases, providing cybersecurity professionals and IT architects with actionable insights, command-level comparisons, and migration strategies to ensure your infrastructure remains secure, scalable, and compliant.
Learning Objectives:
- Understand the architectural differences between RHEL 9’s mature stability and RHEL 10’s image‑based, cloud‑native approach.
- Master essential Linux commands and security hardening techniques applicable to both RHEL 9 and RHEL 10 environments.
- Develop a step‑by‑step migration playbook that incorporates DevSecOps principles, container security, and automated compliance checking.
- Understanding the Core Shift: From Package‑Based to Image‑Mode Management
RHEL 9 follows the traditional package‑based model where system administrators manage individual RPM packages, dependencies, and updates using tools like `dnf` and yum. While this approach offers granular control, it often leads to configuration drift across fleets of servers. RHEL 10 introduces Image Mode, a paradigm shift that treats the operating system as a container image. This enables organizations to build, sign, and deploy immutable OS images using container registries, ensuring that every deployment is identical and verifiable.
Why This Matters for Security:
Immutable infrastructures reduce the attack surface by eliminating persistent state that attackers can exploit. When combined with signed images and attestation, Image Mode provides a cryptographically verifiable chain of custody from build to runtime.
Step‑by‑Step Guide – Building an Immutable RHEL 10 Image:
1. Install the Image Builder Tool:
sudo dnf install osbuild-composer cockpit-composer -y sudo systemctl enable --1ow osbuild-composer.socket
2. Create a Blueprint File (blueprint.toml): Define the packages and services your image requires. For a hardened web server:
name = "hardened-web-server" description = "RHEL 10 image with security profiles" version = "1.0.0" [[bash]] name = "httpd" version = "2.4." [[customizations.user]] name = "admin" password = "encrypted-password-here" groups = ["wheel"]
3. Build the Image:
sudo composer-cli blueprints push blueprint.toml sudo composer-cli blueprints start hardened-web-server image-type qcow2
4. Push to a Container Registry:
sudo skopeo copy oci:hardened-web-server:latest docker://registry.example.com/rhel10-web:latest
5. Deploy on Edge or Cloud: Use the image directly in OpenShift, AWS, or on bare metal with `bootc` to atomically update the entire OS.
- Security Hardening: Comparing SELinux Policies and System Roles
Both RHEL 9 and RHEL 10 leverage SELinux (Security‑Enhanced Linux) as their primary mandatory access control (MAC) system. However, RHEL 10 introduces enhanced SELinux policies tailored for containerized workloads and Kubernetes environments. Additionally, System Roles – Ansible‑based automation modules – have been expanded in RHEL 10 to cover more security controls, including FIPS 140‑3 compliance, STIG (Security Technical Implementation Guide) profiles, and CIS benchmarks.
Key Security Commands Across Both Versions:
- Check SELinux status: `sestatus`
– Change SELinux mode temporarily: `sudo setenforce 0` (Permissive) or `sudo setenforce 1` (Enforcing) - List all SELinux booleans: `sudo getsebool -a`
– Apply a CIS profile using OpenSCAP:sudo oscap xccdf eval --profile xccdf_org.ssgproject.content_profile_cis --results scan-results.xml /usr/share/xml/scap/ssg/content/ssg-rhel10-ds.xml
- Remediate findings automatically:
sudo oscap xccdf eval --remediate --profile xccdf_org.ssgproject.content_profile_cis /usr/share/xml/scap/ssg/content/ssg-rhel10-ds.xml
Step‑by‑Step Guide – Applying a Security Profile via System Roles (RHEL 10):
1. Install the required Ansible collection:
ansible-galaxy collection install redhat.rhel_system_roles
2. Create a playbook (`secure-server.yml`):
- hosts: all roles: - redhat.rhel_system_roles.selinux - redhat.rhel_system_roles.certificate vars: selinux_state: enforcing selinux_policies: - container - virt crypto_policies: FUTURE
3. Run the playbook:
ansible-playbook -i inventory.ini secure-server.yml
- Cloud‑Native and Container Security: Podman, Skopeo, and Buildah
RHEL 9 already supports Podman (daemonless container engine), Skopeo (container image inspection and signing), and Buildah (building OCI images). However, RHEL 10 deepens this integration by making these tools the default workflow for system administration. This shift requires security teams to adapt their container threat modeling and runtime defense strategies.
Critical Security Practices for Containerized RHEL:
- Image Signing: Use `skopeo` to sign images with GPG keys before deployment.
skopeo copy --sign-by [email protected] docker://registry.example.com/app:latest docker://registry.example.com/app:signed
- Vulnerability Scanning: Integrate `clair` or `trivy` into your CI/CD pipeline to scan images for known CVEs before they are promoted to production.
- Runtime Security: Use `podman` with `–security-opt` flags to limit capabilities, disable privilege escalation, and set seccomp profiles.
podman run --security-opt=no-1ew-privileges --cap-drop=ALL --cap-add=NET_BIND_SERVICE -d nginx
Step‑by‑Step Guide – Building a Hardened Container Image with Buildah:
1. Create a `Containerfile`:
FROM registry.access.redhat.com/ubi10/ubi-minimal:latest RUN microdnf install -y httpd && microdnf clean all RUN echo "ServerTokens Prod" >> /etc/httpd/conf/httpd.conf EXPOSE 80 CMD ["httpd", "-D", "FOREGROUND"]
2. Build the image:
buildah bud -t hardened-httpd .
3. Inspect and scan:
buildah inspect hardened-httpd trivy image hardened-httpd
4. Push to registry:
buildah push hardened-httpd docker://registry.example.com/hardened-httpd:latest
- Automation and GitOps: Ansible Automation Platform and Event‑Driven Ansible
RHEL 10 is designed to be automation‑first, aligning with GitOps practices where infrastructure is declared as code and stored in version control. The Ansible Automation Platform is fully supported, and Event‑Driven Ansible (EDA) is a first‑class citizen in RHEL 10, allowing security teams to respond automatically to system events – such as failed login attempts or unauthorized configuration changes.
Step‑by‑Step Guide – Setting Up Event‑Driven Ansible for Security Response:
1. Install EDA:
sudo dnf install ansible-event-driven -y
2. Create a rulebook (`security-response.yml`):
- name: Respond to SSH failures hosts: all sources: - name: listen for auth logs ansible.eda.systemd_journal: matches: - _SYSTEMD_UNIT: sshd.service - MESSAGE: "Failed password" rules: - name: block IP on repeated failures condition: event.meta.count > 3 action: run_playbook: name: block-ip.yml
3. Define the blocking playbook (`block-ip.yml`):
- hosts: all
tasks:
- name: Add IP to firewall blacklist
ansible.builtin.firewalld:
source: "{{ event.source_ip }}"
state: enabled
permanent: true
zone: drop
4. Run EDA:
ansible-rulebook --rulebook security-response.yml --inventory inventory.ini --verbose
- AI‑Assisted Administration: Integrating Large Language Models for Operational Efficiency
RHEL 10 places a stronger emphasis on AI‑assisted administration, with integrations that allow system administrators to use natural language to query system states, generate Ansible playbooks, and troubleshoot issues. While this is a productivity booster, it introduces new security considerations: prompt injection, data leakage, and the need for robust access controls on AI models.
Practical Command – Using the RHEL AI Assistant (Preview):
sudo rhel-ai ask "What are the top 5 security advisories for my system?" sudo rhel-ai ask "Generate an Ansible task to disable root SSH login"
Security Recommendation:
Always run AI tools in a sandboxed environment with restricted network access. Audit all generated code before execution and never provide sensitive system information to external models.
- Migration Strategy: From RHEL 9 to RHEL 10
Migrating from RHEL 9 to RHEL 10 is not a simple in‑place upgrade; it requires a re‑architecture of how you build, deploy, and manage your operating system. The recommended approach is to adopt a blue‑green deployment strategy, where new RHEL 10 images are built and tested alongside existing RHEL 9 workloads.
Step‑by‑Step Migration Guide:
- Inventory and Dependency Mapping: Use `rpm -qa` to list all installed packages on RHEL 9. Check for compatibility with RHEL 10 using the Red Hat Compatibility Matrix.
- Build a Parallel Environment: Deploy RHEL 10 instances in a staging environment. Use the Image Builder (as shown in Section 1) to create reproducible images.
- Automate Configuration Drift Detection: Use Ansible to compare configurations between RHEL 9 and RHEL 10.
ansible-playbook -i rhel9-inventory.ini compare-config.yml ansible-playbook -i rhel10-inventory.ini compare-config.yml
- Test Security Controls: Run the same OpenSCAP profiles on both environments and ensure compliance scores are equal or better on RHEL 10.
- Canary Deployment: Route a small percentage of production traffic to RHEL 10 instances. Monitor with tools like Prometheus and Grafana.
- Full Cutover: Once confidence is high, scale the RHEL 10 fleet and decommission RHEL 9 nodes.
7. Windows Integration: Managing Mixed Environments
In many enterprises, RHEL coexists with Windows Server. RHEL 10 improves interoperability through AD Bridge and SMB 3.1.1 support, enabling seamless file sharing and authentication.
Command – Joining RHEL 10 to Active Directory:
sudo realm join --user=Administrator domain.example.com sudo realm permit -g "Domain Admins"
Command – Mounting a Windows SMB Share Securely:
sudo mount -t cifs //windows-server/share /mnt/share -o username=user,password=pass,vers=3.1.1,sec=krb5
Security Note: Always use Kerberos authentication (sec=krb5) and enable SMB encryption (seal) to protect data in transit.
What Undercode Say:
- Key Takeaway 1: RHEL 10 is not merely an incremental update; it is a fundamental rethinking of how enterprise Linux is deployed and secured. The shift to Image Mode and container‑native workflows demands that security teams modernize their DevSecOps pipelines, integrating image scanning, signing, and attestation from day one.
- Key Takeaway 2: Automation is the new perimeter. With Event‑Driven Ansible and AI‑assisted administration, RHEL 10 empowers organizations to respond to threats in real time. However, this also means that misconfigurations in automation playbooks can have widespread consequences. Rigorous version control, peer review, and automated testing of automation code are non‑negotiable.
Analysis:
The evolution from RHEL 9 to RHEL 10 mirrors the broader industry shift from pets to cattle, from mutable servers to immutable infrastructure. For cybersecurity professionals, this transition offers an opportunity to embed security earlier in the lifecycle – shifting left in the truest sense. However, it also introduces new attack vectors: container escapes, registry poisoning, and supply chain attacks against base images. Organizations must invest in robust container security tooling, including runtime protection (e.g., Falco), and enforce strict policies around image sources and update frequencies. Moreover, the human element remains critical; training teams on Image Mode, Podman, and Ansible Automation Platform is just as important as deploying the technology itself. RHEL 10 is a powerful platform, but its security posture ultimately depends on the expertise and vigilance of the administrators operating it.
Prediction:
- +1 RHEL 10’s Image Mode will catalyze a wave of innovation in immutable infrastructure, leading to faster patch cycles and reduced mean time to recovery (MTTR) from security incidents. Organizations that adopt early will gain a competitive advantage in resilience and compliance.
- +1 The integration of AI‑assisted administration will democratize Linux expertise, allowing junior engineers to perform complex troubleshooting and security tasks with guided assistance, thereby alleviating the talent shortage in cybersecurity.
- -1 The complexity of migrating from RHEL 9 to RHEL 10 will create a temporary spike in misconfigurations, particularly around SELinux policies and container networking, potentially exposing systems to lateral movement attacks if not carefully managed.
- -1 As container registries become the new source of truth for OS images, they will become prime targets for supply chain attacks. Organizations must prioritize registry security, including access controls, image vulnerability scanning, and immutable tags, to prevent widespread compromise.
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