Linux

Common Problems 116622

Ubuntu 24.04 LTS – Docker service fails after cgroup configuration mismatch

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 24.04 LTS Ubuntu 24.04 Ubuntu 24.04.1 📖 ~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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Common Problems 120699

Debian 11 – Fail2ban blocks internal monitoring and trusted hosts

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Debian 11 📖 ~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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Common Problems 116119

Ubuntu 26.04 LTS – fail2ban bans trusted subnet due to aggressive jail policy

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 26.04 LTS Ubuntu 26.04 Ubuntu 26.04.1 📖 ~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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Common Problems 117628

Ubuntu 20.04 LTS – certbot renewal fails because port 80 is in use

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 20.04 LTS Ubuntu 20.04 Ubuntu 20.04.6 📖 ~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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Common Problems 120182

Debian 12 – PostgreSQL fails to start due to data directory permissions

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Debian 12 📖 ~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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Common Problems 114125

RHEL 10 – PAM faillock locks service accounts after automation retries

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: RHEL 10 RHEL 10.0 RHEL 10.1 📖 ~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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Common Problems 117119

Ubuntu 22.04 LTS – Python venv pip install fails due to externally managed environment confusion

🟡 Medium   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 22.04 LTS Ubuntu 22.04 Ubuntu 22.04.4 📖 ~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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Common Problems 116612

Ubuntu 24.04 LTS – certbot renew fails due to challenge and webroot mismatch

🟠 High   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 24.04 LTS Ubuntu 24.04 Ubuntu 24.04.1 📖 ~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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Common Problems 120171

Debian 12 – MariaDB fails to start due to InnoDB corruption

🔴 Critical   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Debian 12 📖 ~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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Common Problems 117618

Ubuntu 20.04 LTS – UFW blocks SSH access after firewall enable

🔴 Critical   ⏱ 5–30 min  Last verified: 20 May 2026 Affected versions: Ubuntu 20.04 LTS Ubuntu 20.04 Ubuntu 20.04.6 📖 ~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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