https://hossein.cloud/blog/ Practical notes on infrastructure, DevOps, LLM operations, and RAG systems. en Tue, 13 Oct 2026 08:00:00 GMT https://hossein.cloud/blog/posts/kubernetes-limited-kubeconfig-selected-namespaces.html https://hossein.cloud/blog/posts/kubernetes-limited-kubeconfig-selected-namespaces.html Tue, 13 Oct 2026 08:00:00 GMT Create a namespace-limited kubeconfig with one ServiceAccount token, a reusable ClusterRole, and explicit RoleBindings. Kubernetes https://hossein.cloud/blog/posts/linux-disk-full-docker-overlay2-elasticsearch-cleanup.html https://hossein.cloud/blog/posts/linux-disk-full-docker-overlay2-elasticsearch-cleanup.html Mon, 12 Oct 2026 08:00:00 GMT Find disk consumers, diagnose damaged Docker layers, and reclaim Elasticsearch storage through supported APIs. Linux https://hossein.cloud/blog/posts/kubernetes-namespace-and-pvc-stuck-terminating-cleanup.html https://hossein.cloud/blog/posts/kubernetes-namespace-and-pvc-stuck-terminating-cleanup.html Sun, 11 Oct 2026 08:00:00 GMT A command-first runbook for namespace deletion, PVC protection, Longhorn finalizers, and deliberate storage cleanup. Kubernetes https://hossein.cloud/blog/posts/troubleshooting-kubernetes-memory-and-nodejs-oomkills.html https://hossein.cloud/blog/posts/troubleshooting-kubernetes-memory-and-nodejs-oomkills.html Sat, 10 Oct 2026 06:05:45 GMT A Kubernetes and Node.js memory runbook: cgroups, process RSS, V8 headroom, Next.js retention, heap snapshots, and GC diagnostics. Kubernetes https://hossein.cloud/blog/posts/stock-options-in-the-iranian-market.html https://hossein.cloud/blog/posts/stock-options-in-the-iranian-market.html Tue, 06 Oct 2026 07:10:01 GMT An options reference with verified arithmetic, rial/toman checks, conditional payoff scenarios, and exercise-funding calculations. Markets https://hossein.cloud/blog/posts/restoring-a-gzip-mongodb-backup-in-docker.html https://hossein.cloud/blog/posts/restoring-a-gzip-mongodb-backup-in-docker.html Tue, 06 Oct 2026 06:55:18 GMT A MongoDB restore runbook covering Docker, gzip archives, authentication, verification, and common restore failures. MongoDB https://hossein.cloud/blog/posts/archiving-and-compressing-directories-in-linux.html https://hossein.cloud/blog/posts/archiving-and-compressing-directories-in-linux.html Tue, 06 Oct 2026 06:42:13 GMT A Linux command reference for creating, extracting, listing, and checking tar, gzip, and zip archives. Linux https://hossein.cloud/blog/posts/building-a-floating-ip-with-keepalived-for-linux-high-availability.html https://hossein.cloud/blog/posts/building-a-floating-ip-with-keepalived-for-linux-high-availability.html Mon, 05 Oct 2026 13:29:42 GMT A practical two-VM Keepalived setup with VRRP, VIP failover drills, application health checks, and network troubleshooting. Networking https://hossein.cloud/blog/posts/why-my-active-active-haproxy-setup-failed.html https://hossein.cloud/blog/posts/why-my-active-active-haproxy-setup-failed.html Mon, 05 Oct 2026 08:00:00 GMT A real-world look at why one shared loopback VIP caused uneven traffic and stale ARP paths—and how VRRP, ECMP/BGP, or DNS change the design. https://hossein.cloud/blog/posts/making-kubernetes-workloads-boring-to-operate.html https://hossein.cloud/blog/posts/making-kubernetes-workloads-boring-to-operate.html Tue, 29 Sep 2026 07:00:00 GMT A practical reliability baseline for probes, graceful shutdowns, rollout safety, resource limits, and failure drills. https://hossein.cloud/blog/posts/treat-terraform-state-like-production-data.html https://hossein.cloud/blog/posts/treat-terraform-state-like-production-data.html Tue, 29 Sep 2026 06:00:00 GMT A safer workflow for remote state, locking, reviewed plans, refactors, and recovery without risky manual edits. https://hossein.cloud/blog/posts/a-repeatable-path-from-alert-to-cause.html https://hossein.cloud/blog/posts/a-repeatable-path-from-alert-to-cause.html Mon, 28 Sep 2026 08:00:00 GMT A simple incident workflow that connects service-level metrics, deployments, structured logs, and traces. https://hossein.cloud/blog/posts/a-small-rag-service-i-would-actually-deploy.html https://hossein.cloud/blog/posts/a-small-rag-service-i-would-actually-deploy.html Mon, 28 Sep 2026 07:00:00 GMT A reference architecture for permission-aware retrieval, citations, evaluation, and safe operations. https://hossein.cloud/blog/posts/one-controlled-gateway-for-llm-traffic.html https://hossein.cloud/blog/posts/one-controlled-gateway-for-llm-traffic.html Sun, 27 Sep 2026 08:00:00 GMT A gateway pattern for model routing, budgets, retries, telemetry, and guardrails shared across applications.