Filesystem

How to Manage Disk Encryption with LUKS and cryptsetup on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Manage Disk Encryption with LUKS and cryptsetup on RHEL 8

Disk encryption is a critical layer of defense-in-depth for any Linux server handling sensitive data. LUKS (Linux Unified Key Setup) is the standard on-disk format for Linux disk encryption, and cryptsetup is the user-space tool that manages it. On RHEL 8, LUKS2 is the default format, bringing improved metadata handling, larger headers, and support for […]

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How to Configure PostgreSQL Remote Access on FreeBSD 12 — step-by-step FreeBSD 12 tutorial on Progressive Robot

How to Configure PostgreSQL Remote Access on FreeBSD 12

Introduction How to Configure PostgreSQL Remote Access on FreeBSD 12 is a core administration task for any FreeBSD 12 server operator. FreeBSD 12 ships with the 15.0-RELEASE kernel, ZFS as the default root filesystem, Capsicum capability sandboxing improvements, and an updated ports tree. Unlike Linux distributions, FreeBSD uses rc(8) for service management, pf for packet […]

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How to Set Up a Ceph Storage Cluster on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Set Up a Ceph Storage Cluster on RHEL 8

Ceph is a unified, distributed storage system that simultaneously provides object, block, and file storage on commodity hardware. It eliminates single points of failure through replication and erasure coding, and scales linearly by adding nodes. The cephadm tool, introduced in Ceph Octopus, simplifies cluster deployment by using containers (Podman on RHEL 8) to manage Ceph […]

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How to Install and Configure cAdvisor for Container Monitoring on RHEL 8 — step-by-step RHEL 8 tutorial on Progressive Robot

How to Install and Configure cAdvisor for Container Monitoring on RHEL 8

cAdvisor (Container Advisor) is an open-source daemon from Google that collects, aggregates, and exports real-time resource usage and performance metrics for every running container on a host. Unlike Node Exporter, which reports host-level statistics, cAdvisor descends into cgroup hierarchies to expose per-container CPU, memory, network, and filesystem metrics in Prometheus format. On RHEL 8 with […]

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Common Problems 115122

RHEL 8 MariaDB service fails to start after data directory move

🟡 Medium   ⏱ 5–30 min  Last verified: 24 June 2019 📖 ~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 Install Nomad on FreeBSD 12 — step-by-step FreeBSD 12 tutorial on Progressive Robot

How to Install Nomad on FreeBSD 12

Introduction How to Install Nomad on FreeBSD 12 is a core administration task for any FreeBSD 12 server operator. FreeBSD 12 ships with the 15.0-RELEASE kernel, ZFS as the default root filesystem, Capsicum capability sandboxing improvements, and an updated ports tree. Unlike Linux distributions, FreeBSD uses rc(8) for service management, pf for packet filtering, and […]

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Common Problems 119053

Ubuntu 14.04 LTS Apache returns 500 Internal Server Error

🟡 Medium   ⏱ 5–30 min  Last verified: 23 June 2019 📖 ~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 115060

Multipath device map missing on startup

🟡 Medium   ⏱ 5–30 min  Last verified: 22 June 2019 📖 ~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 115052

RHEL 8 System Falls Into Emergency Mode Due to fstab Mistake

🔴 Critical   ⏱ 5–30 min  Last verified: 22 June 2019 Affected versions: 8.4 8.5 8.6 8.7 8.8 8.9 8.10 📖 ~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 […]

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How to Configure Kubernetes Persistent Volumes and Storage Classes on RHEL 7 — step-by-step RHEL 7 tutorial on Progressive Robot

How to Configure Kubernetes Persistent Volumes and Storage Classes on RHEL 7

How to Configure Kubernetes Persistent Volumes and Storage Classes on RHEL 7 By default, storage inside a Kubernetes Pod is ephemeral — when a Pod restarts or is rescheduled, all data written to the container filesystem is lost. For applications like databases, file servers, and message queues that require durable storage, Kubernetes provides a storage […]

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