RHEL 9

Common Problems 114396

DNF Metadata Download Timeout on RHEL 9

🟡 Medium   ⏱ 5–30 min  Last verified: 13 November 2023 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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How to Deploy Applications with Docker Compose on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Deploy Applications with Docker Compose on RHEL 9

Docker Compose transforms multi-container application deployment from a series of manual docker run commands into a declarative, version-controlled configuration. A production-ready Compose deployment includes health checks (to ensure services are truly ready before dependent services start), resource limits (to prevent runaway containers from consuming all host resources), restart policies (to automatically recover from failures), and […]

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How to Configure IPv6 Dual-Stack Networking on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure IPv6 Dual-Stack Networking on RHEL 9

IPv6 adoption continues to accelerate as IPv4 address space is exhausted, and most production servers now need to serve traffic over both protocols simultaneously. RHEL 9 supports dual-stack networking natively through NetworkManager, allowing IPv4 and IPv6 addresses to coexist on the same interface without additional kernel modules. Configuring dual-stack correctly involves not only assigning addresses […]

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How to Install HashiCorp Vault for Secrets Management on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install HashiCorp Vault for Secrets Management on RHEL 9

HashiCorp Vault is an open-source secrets management platform that provides secure storage, access control, and auditing for sensitive data such as API keys, passwords, certificates, and encryption keys. Instead of hardcoding secrets in application configs or environment variables, applications request them from Vault at runtime using short-lived tokens or AppRole credentials. This tutorial covers installing […]

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Common Problems 114607

systemd Unit Start Times Out Waiting For Dependencies

🟡 Medium   ⏱ 5–30 min  Last verified: 29 October 2023 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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How to Configure Prometheus Node Exporter on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Prometheus Node Exporter on RHEL 9

Prometheus Node Exporter is the standard agent for exposing hardware and operating system metrics from Linux hosts to a Prometheus server. It collects data on CPU usage, memory, disk I/O, network throughput, filesystem utilisation, and dozens of other system-level indicators, making them available via a simple HTTP endpoint on port 9100. Installing Node Exporter on […]

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How to Install and Configure OpenVPN on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install and Configure OpenVPN on RHEL 9

OpenVPN is a mature, battle-tested VPN solution that supports TLS-based encryption and X.509 certificate authentication, making it well-suited for enterprise environments where certificate lifecycle management and strong mutual authentication are required. Unlike WireGuard, OpenVPN can traverse firewalls over TCP port 443, which is useful when UDP is blocked. On RHEL 9, OpenVPN 2.x is available […]

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How to Deploy a Ruby on Rails Application on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Deploy a Ruby on Rails Application on RHEL 9

Ruby on Rails (Rails) is a full-stack web application framework built on Ruby that made convention-over-configuration and the MVC pattern mainstream in web development. Rails provides ActiveRecord (ORM), ActionController (routing and controllers), ActionView (templating with ERB/Haml), ActionMailer, ActiveJob (background jobs), ActionCable (WebSockets), and a comprehensive set of security defaults out of the box. A Rails […]

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Common Problems 114586

OOM Killer Terminates Application on RHEL 9

🟡 Medium   ⏱ 5–30 min  Last verified: 12 October 2023 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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Common Problems 114578

sudo In Automation Fails Due To Policy Or TTY Expectations

🟡 Medium   ⏱ 5–30 min  Last verified: 10 October 2023 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related Errors & Cross-Refs References & Further […]

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