RHEL 7

Common Problems 115454

SELinux Denies httpd Outbound Network Connections

🟡 Medium   ⏱ 5–30 min  Last verified: 19 September 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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How to Monitor MySQL with Percona Monitoring and Management on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Monitor MySQL with Percona Monitoring and Management on RHEL 7

How to Monitor MySQL with Percona Monitoring and Management on RHEL 7 Percona Monitoring and Management (PMM) is a free, open-source platform for monitoring MySQL, MariaDB, PostgreSQL, and MongoDB. It combines Grafana dashboards, Prometheus metrics collection, and Query Analytics (QAN) into a single integrated UI. Unlike generic monitoring tools, PMM understands database internals and surfaces […]

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Common Problems 115399

RHEL 7 systemctl unit failure caused by invalid drop-in override

🟠 High   ⏱ 5–30 min  Last verified: 10 September 2021 Affected versions: RHEL 7 📖 ~2 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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Common Problems 115497

journalctl Shows Repeated Unit Restart Loops

🟡 Medium   ⏱ 5–30 min  Last verified: 7 September 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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How to Harden Nginx: Security Headers, TLS 1.3 and OCSP Stapling on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Harden Nginx: Security Headers, TLS 1.3 and OCSP Stapling on RHEL 7

How to Harden Nginx: Security Headers, TLS 1.3 and OCSP Stapling on RHEL 7 A default Nginx installation exposes unnecessary information about the server software, accepts outdated and broken TLS protocol versions, and omits the HTTP security headers that modern browsers rely on for protection against cross-site scripting, clickjacking, and protocol downgrade attacks. Hardening Nginx […]

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How to Use Percona XtraBackup for MySQL Hot Backups on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Use Percona XtraBackup for MySQL Hot Backups on RHEL 7

How to Use Percona XtraBackup for MySQL Hot Backups on RHEL 7 Taking reliable backups of a live MySQL or MariaDB database without interrupting application traffic is a fundamental requirement for any production system. mysqldump works for small databases but locks tables and can run for hours on large datasets. Percona XtraBackup solves this problem […]

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How to Set Up Vagrant and VirtualBox on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Set Up Vagrant and VirtualBox on RHEL 7

How to Set Up Vagrant and VirtualBox on RHEL 7 Vagrant is an open-source tool by HashiCorp that automates the creation, configuration, and management of virtualized development environments. Combined with VirtualBox as a hypervisor backend, Vagrant allows developers and operations engineers on RHEL 7 to spin up reproducible Linux (or Windows) virtual machines with a […]

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How to Configure VLAN Tagging with 802.1Q on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure VLAN Tagging with 802.1Q on RHEL 7

How to Configure VLAN Tagging with 802.1Q on RHEL 7 VLANs (Virtual Local Area Networks) allow a single physical network interface to participate in multiple logically isolated network segments simultaneously. The 802.1Q standard defines how Ethernet frames are tagged with a 12-bit VLAN ID, enabling switches and hosts to segregate traffic without requiring dedicated physical […]

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Common Problems 115424

RPM Database Lock Conflicts During YUM

🟡 Medium   ⏱ 5–30 min  Last verified: 27 August 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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How to Perform a System Security Audit with auditd on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Perform a System Security Audit with auditd on RHEL 7

How to Perform a System Security Audit with auditd on RHEL 7 Security auditing is a critical practice for any production RHEL 7 system, especially those subject to compliance frameworks such as PCI-DSS, HIPAA, or DISA STIG. The Linux Audit Framework, centered on the auditd daemon, provides kernel-level monitoring of system calls, file access, user […]

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