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Today's IT briefing
Recent pieces chosen for practical usefulness.
git push 'error: RPC failed; HTTP 413': How to Find the Cause and Fix It
Why git push fails with 'RPC failed; HTTP 413' (a server/proxy body limit or a large file), how to confirm it with GIT_TRACE_CURL and cat-file, and how to fix it with an nginx limit, an amended commit, Git LFS or filter-repo. Every command was reproduced in a local sandbox.
Sentry vs Bugsnag Pricing: 100k Errors/Month for a 5-Person Team (2026)
At 100k errors a month, Sentry Team costs about $47.13 before tax. Cost tables for 10k/100k/500k, Bugsnag daily quotas and auto-upgrade rules, and what gets stored on a spike day, from official pricing.
Kafka vs RabbitMQ vs NATS vs Redis Streams: A 6-Question Decision Guide
Compare Kafka, RabbitMQ, NATS JetStream and Redis Streams by delivery model, replay, ordering and ops burden. A 6-question decision table, how to size retention correctly, and first-week metrics.
Engineer reference
Linux, Docker, Git, networking, security, databases — 143+ practical guides you can copy and run.
Recover Commits After git reset --hard — reflog and ORIG_HEAD Runbook
Kubernetes Endpoints None Fix — Empty Service Backends Runbook
Kubernetes ImagePullBackOff Fix — Events Checklist and Commands
keepalived VRRP: Setting Up Virtual IP Failover with Health Checks and Split-Brain Prevention
Kubernetes RBAC: Diagnosing 'Forbidden' Errors and Granting Least-Privilege Access with Roles and ServiceAccounts
PostgreSQL Privileges: Setting Up Read-Only and Least-Privilege Roles with GRANT, REVOKE, and DEFAULT PRIVILEGES
Start from your role
Learning paths by role — from getting started to going deeper to making decisions.
Developers
Tools and patterns that make coding time smarter.
git push 'error: RPC failed; HTTP 413': How to Find the Cause and Fix It
pip install succeeded, but ModuleNotFoundError? Six-way interpreter path diagnosis
Fixing SSLCertVerificationError: Diagnosing 5 Causes of CERTIFICATE_VERIFY_FAILED
AI practitioners
How to fold GPT, Claude, and MCP into real workflows.
DB Schema Changes in CI/CD: Flyway vs Liquibase Comparison and Implementation Guide
When ChatGPT Misses the Target: A Prompt Diagnosis and Revision Sequence
RAG Retrieval Quality Checks: Chunking, Reranking, and Citations
Security
New threat models and practical defenses in the AI era.
kex_exchange_identification: read: Connection reset by peer, 5 SSH Fixes
Entrustment vs. Third-Party Provision of Personal Information: Consent Requirements and Case Comparisons
certificate has expired: a five-branch diagnosis (nginx · openssl)
Seniors & PMs
Async workflows for time, information, and tools.
AI Governance and Regulatory Checklist Before Adoption
Designing AI Tech Blog Content: Organizing LLM, RAG, and Agent Validation Guides into Clusters
3-Step Lead Conversion Strategy Guide: Turning Your Tech Blog into a Revenue Pipeline
Latest
Recently published articles, in chronological order.
Vault vs AWS Secrets Manager vs SOPS: Cost Comparison and Selection Criteria
We compared three secret-management tools by monthly cost formulas and operational burden—not feature checklists. Included: monthly bills for 30, 300, and 1,000 secrets, five SOPS age commands, ESO integration YAML, and how to judge Vault’s BSL license.
Fixing Missing Kubernetes ServiceAccount Tokens and 401 Unauthorized (1.24+)
If a Pod is missing its ServiceAccount token file or returns 401 Unauthorized, you have an authentication problem, not an RBAC problem. This post covers an error-text triage table, version differences after Kubernetes 1.24, automount precedence, and projected-token refresh and revocation.
Fixing no pg_hba.conf entry and password authentication failed by Root Cause
How to map six PostgreSQL connection errors onto the network, pg_hba, and authentication layers and diagnose them in 30 seconds. Covers an error-text lookup table, ss and pg_hba_file_rules diagnostics, first-match rules, PG14 scram-sha-256
Diagnosing Kubernetes MTU Issues — When ping Works but Large Responses Hang
If ping is fine but curl hangs only on large responses and the TLS handshake goes silent, you have an MTU problem. This post covers DF-bit ping binary search, the VXLAN 1450 / GCP 1410 calculation table, where to set Flannel, Calico, and Ci
VictoriaMetrics vs Thanos vs Grafana Cloud: Monthly Cost Comparison (1 Million Time Series)
Monthly KRW cost formulas for Prometheus+Thanos, Grafana Cloud, and VictoriaMetrics at 20 nodes and 1 million active series. Includes a TCO table with ops effort, a 5-axis decision matrix, cardinality-explosion response, and a migration run
Diagnosing 504 Gateway Time-out: An nginx · ALB · gunicorn Timeout Alignment Runbook
A procedure for pinpointing which of CloudFront, ALB, nginx, or gunicorn hung up first when a 504 Gateway Time-out appears, using only curl instrumentation and response headers. Covers per-layer timeout tables, alignment principles, and how
pip install succeeded, but ModuleNotFoundError? Six-way interpreter path diagnosis
pip install succeeded but import still fails? Instead of reinstalling, compare the running interpreter and pip install paths with four commands, pin the cause to one of six branches, and apply one-line fixes plus recurrence prevention for v
Go deeper with series
Step-by-step learning paths designed to be read in order.
LLM agents
A 20-part series. Reading from part 1 in order makes it easiest to follow.
Kubernetes troubleshooting
A 14-part series. Reading from part 1 in order makes it easiest to follow.
LLM application architecture
A 10-part series. Reading from part 1 in order makes it easiest to follow.
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