RHEL 7

How to Set Up ModSecurity WAF with Apache on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Set Up ModSecurity WAF with Apache on RHEL 7

How to Set Up ModSecurity WAF with Apache on RHEL 7 ModSecurity is the most widely deployed open-source Web Application Firewall (WAF), and it integrates natively with Apache as a dynamic module. When paired with the OWASP Core Rule Set (CRS), ModSecurity can detect and block a broad range of web attacks including SQL injection, […]

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How to Install and Configure Memcached on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install and Configure Memcached on RHEL 7

How to Install and Configure Memcached on RHEL 7 Memcached is a high-performance, distributed memory object caching system used to speed up dynamic web applications by reducing database load. It stores frequently requested data — such as database query results, session data, and rendered page fragments — in RAM, allowing subsequent requests to be served […]

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How to Install and Configure cAdvisor for Container Monitoring on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Install and Configure cAdvisor for Container Monitoring on RHEL 7

How to Install and Configure cAdvisor for Container Monitoring on RHEL 7 cAdvisor (Container Advisor) is an open-source agent developed by Google that collects, aggregates, processes, and exports resource usage and performance metrics for running containers. It provides a real-time web UI and a Prometheus-compatible metrics endpoint, making it the standard solution for container observability […]

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How to Set Up Port Knocking for SSH on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Set Up Port Knocking for SSH on RHEL 7

How to Set Up Port Knocking for SSH on RHEL 7 Port knocking is a stealthy technique for controlling access to network services by requiring a client to send connection attempts to a predefined sequence of closed ports before a firewall rule opens the target port. When applied to SSH, it effectively hides port 22 […]

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Common Problems 115576

RHEL 7 systemctl Target Misconfiguration Boots into Rescue Mode

🟠 High   ⏱ 5–30 min  Last verified: 24 March 2021 Affected versions: RHEL 7 📖 ~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 & […]

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How to Use Skaffold for Kubernetes Development on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Use Skaffold for Kubernetes Development on RHEL 7

How to Use Skaffold for Kubernetes Development on RHEL 7 One of the most tedious aspects of Kubernetes development is the inner loop: make a code change, build a container image, push it to a registry, update the Kubernetes manifest, apply it to the cluster, and wait for the rolling update — repeated dozens of […]

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How to Configure Nginx as a Reverse Proxy on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Nginx as a Reverse Proxy on RHEL 7

How to Configure Nginx as a Reverse Proxy on RHEL 7 A reverse proxy sits in front of one or more backend application servers, forwarding incoming client requests and returning the backend responses. Nginx is exceptionally well-suited for this role due to its event-driven architecture and low memory footprint. On RHEL 7, a common pattern […]

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Common Problems 115636

firewalld Blocking Required Application Port – RHEL 7 Post 107

🟡 Medium   ⏱ 5–30 min  Last verified: 14 March 2021 📖 ~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 115577

systemctl Restart Hangs Because Dependency Is Deadlocked

🟡 Medium   ⏱ 5–30 min  Last verified: 5 March 2021 📖 ~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 115527

firewalld Zone Misassignment Breaks App Reachability

🟡 Medium   ⏱ 5–30 min  Last verified: 5 March 2021 📖 ~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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