authentication

Common Problems 116115

Ubuntu 26.04 LTS – Failed sudo due to broken PAM configuration – Fix & Prevention

šŸ”“ Critical   ā± 5–30 min  Last verified: 5 June 2026 Affected versions: Ubuntu 26.04 LTS šŸ“– ~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 Take a System Snapshot Before Upgrades on RHEL 10 — step-by-step RHEL 10 tutorial on Progressive Robot

How to Take a System Snapshot Before Upgrades on RHEL 10

Introduction Setting up take a system snapshot before upgrades on a RHEL 10 server is a common task for system administrators, DevOps engineers, and site reliability engineers. This guide explains how to Take a System Snapshot Before Upgrades on RHEL 10, with all the commands you need, the SELinux and firewalld considerations to keep in […]

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How to Monitor Kubernetes with Prometheus and Grafana on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor Kubernetes with Prometheus and Grafana on RHEL 9

Prometheus and Grafana are the de facto standard monitoring stack for Kubernetes clusters. Prometheus is a time-series metrics database that scrapes metrics from Kubernetes components (API server, kubelet, etcd) and from applications via HTTP endpoints in a pull-based model. Grafana is a visualisation platform that queries Prometheus and displays metrics as interactive dashboards. The kube-prometheus-stack […]

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Common Problems 116051

Ubuntu 26.04 LTS – NVIDIA driver mismatch after kernel update – Fix & Prevention

🟠 High   ā± 5–30 min  Last verified: 3 June 2026 Affected versions: Ubuntu 26.04 LTS šŸ“– ~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 Set Up Two-Factor Authentication (2FA) for SSH on Ubuntu 26.04 — step-by-step Linux tutorial on Progressive Robot

How to Set Up Automatic Login Banners and SSH Warnings on Ubuntu 26.04

Login banners and MOTD (Message of the Day) serve both legal and operational purposes: they warn unauthorised users, satisfy compliance requirements (PCI-DSS, HIPAA, SOC 2), and display important system information to admins. This guide configures SSH banners and MOTD on Ubuntu 26.04 LTS. Tested and valid on: Ubuntu 26.04 LTS Prerequisites Ubuntu 26.04 LTS A […]

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Common Problems 116083

Fix Docker Socket Permission Denied on Ubuntu 26.04 LTS

🟔 Medium   ā± 5–30 min  Last verified: 3 June 2026 Affected versions: 26.04 šŸ“– ~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 […]

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How to Monitor MariaDB with mysqld_exporter on RHEL 10 — step-by-step RHEL 10 tutorial on Progressive Robot

How to Monitor MariaDB with mysqld_exporter on RHEL 10

Introduction RHEL 10 ships with a stable, security-hardened base that makes deploying monitor mariadb with mysqld_exporter both straightforward and auditable. This tutorial covers the complete procedure for how to Monitor MariaDB with mysqld_exporter on RHEL 10, including dnf module streams where applicable, systemd unit management, and the firewalld rules required for network-facing services. Prerequisites You […]

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How to Install Vagrant with libvirt on RHEL 10 — step-by-step RHEL 10 tutorial on Progressive Robot

How to Install Vagrant with libvirt on RHEL 10

Introduction This tutorial demonstrates how to Install Vagrant with libvirt on RHEL 10 on RHEL 10. It is written for administrators who want a repeatable, well-explained walkthrough that goes beyond a bare command list and explains each configuration choice. Every command is tested against a freshly registered RHEL 10 system with the default AppStream repositories […]

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How to Install Java OpenJDK 21 on RHEL 10 — step-by-step RHEL 10 tutorial on Progressive Robot

How to Install Java OpenJDK 21 on RHEL 10

Introduction This tutorial demonstrates how to Install Java OpenJDK 21 on RHEL 10 on RHEL 10. It is written for administrators who want a repeatable, well-explained walkthrough that goes beyond a bare command list and explains each configuration choice. Every command is tested against a freshly registered RHEL 10 system with the default AppStream repositories […]

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How to Configure DNS Forwarding with Unbound on RHEL 10 — step-by-step RHEL 10 tutorial on Progressive Robot

How to Configure DNS Forwarding with Unbound on RHEL 10

Introduction This tutorial demonstrates how to Configure DNS Forwarding with Unbound on RHEL 10 on RHEL 10. It is written for administrators who want a repeatable, well-explained walkthrough that goes beyond a bare command list and explains each configuration choice. Every command is tested against a freshly registered RHEL 10 system with the default AppStream […]

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