DevOps on Vinh Thang's AI Tech Notes

🌐 Expanding to Multi-Cloud: Provisioning Oracle Linux 10 on Google Cloud's $0 Always Free Tier & Joining K3s

Thu, 27 Aug 2026 19:45:00 +0700

Why settle for one free cloud provider when you can build an automated, resilient multi-cloud Kubernetes cluster across Oracle Cloud (OCI) and Google Cloud Platform (GCP) — completely for $0/month?

In this post, I walk through the end-to-end process of:

Provisioning an Oracle Linux Server 10.1 instance on Google Cloud’s Always Free Tier (gce10).
Applying kernel and daemon memory hardening to reclaim ~250 MB of RAM.
Joining gce10 as a worker node into our central K3s Kubernetes cluster across a secure WireGuard mesh.
Running a head-to-head performance benchmark comparing Apple Silicon M1, OCI Ampere ARM (arm10), GCP Intel Xeon (gce10), and OCI AMD EPYC (amd10/amd11).

🏛️ 1. Multi-Cloud K3s Kubernetes Fleet Architecture

Our fleet previously lived entirely in OCI Tokyo. Adding gce10 in GCP Iowa (us-central1) creates a geo-distributed cross-cloud presence with a dedicated US edge outpost.

🛠️ Building a Production-Grade Home Cloud on Oracle's $0 Always Free Tier

Fri, 21 Aug 2026 00:21:00 +0700

What can you actually run on a $0/month Always Free cloud server?

In this post, I document the end-to-end journey of turning an Oracle Cloud 1 GB AMD Micro instance (amd10) in Tokyo into a multi-service personal cloud hub — complete with Dual-Stack DNS ad-blocking, Google Single Sign-On (SSO), lossless Hi-Res music streaming, a Rust-powered REST & AI MCP API, and a Hugo static blog.

🏗️ Architecture & Network Blueprint

graph TD
Internet["🌐 Internet / Home Network / Mobile"] --> Caddy["🔒 Caddy (Auto Let's Encrypt SSL)"]
subgraph OCI Cloud Instance (amd10 - Tokyo)
Caddy -->|/| VietCal["📅 VietCalendar REST & MCP (Rust :8080)"]
Caddy -->|files.*| Oauth["🔑 OAuth2-Proxy (Google SSO :4180)"]
Oauth --> FileBrowser["📁 FileBrowser Cloud Drive (:8082)"]
Caddy -->|music.*| Navidrome["🎵 Navidrome Lossless FLAC (:4533)"]
Caddy -->|blog.*| Hugo["📝 Hugo Static Site (:443)"]
Caddy -->|adguard.*| AdGuardWeb["🛡️ AdGuard Dashboard (:3000)"]
Router["🏠 Home Router (Fiber IPv4 & IPv6)"] --> AdGuardDNS["🛡️ AdGuard DNS Server (:53 & :853 DoT)"]
end

⚡ 1. Reclaiming Hardware RAM (The `crashkernel` Discovery)

On a standard 1 GB VM, Linux kdump can silently reserve up to 448 MB RAM (nearly half the server’s memory!).

Building an Ultra-Lightweight Cloud-Native Observability & Analytics Stack: Metrics, Logs, Traces & Status on OCI

Mon, 24 Aug 2026 23:35:00 +0700

Running a complex fleet of microservices—spanning AI document assistants, vector databases, lossless audio streamers, private DNS resolvers, and astronomical APIs—demands complete, real-time visibility. But traditional enterprise observability suites (Elasticsearch, heavy Prometheus clusters, DataDog) frequently devour gigabytes of memory and CPU cycles just to monitor a small infrastructure.

In this deep dive, I break down how we architected and deployed a complete, ultra-lightweight, 360-degree Observability, Logging, Analytics, and Uptime Stack across our 3-node hybrid cloud fleet at vinhthang.dev, maintaining sub-millisecond query latencies while consuming less than 250 MB total RAM!

Supercharging Self-Hosted Cloud Uploads: How Cloudflare WARP Turbocharges File Ingestion

Mon, 24 Aug 2026 19:14:00 +0700

One of the most frustrating bottlenecks in self-hosting is uploading large files to overseas cloud servers.

Whether you are uploading a 45 GB lossless FLAC music collection to Navidrome, backing up 4K video files to FileBrowser, or transferring gigabytes of PDF datasets to an AI vector store, standard public internet routing often degrades performance to an agonizing crawl.

In this post, I will explain why international cross-border uploads stall, and how we used Cloudflare WARP and Anycast Edge Ingestion to boost our file upload throughput by 5x to 10x directly into our cloud fleet at vinhthang.dev.

How to Snag the Elusive Oracle Cloud Always Free ARM64 Ampere A1 Instance

Mon, 24 Aug 2026 18:45:00 +0700

If you have ever tried to launch an ARM64 Ampere A1 Flex compute instance on Oracle Cloud Infrastructure (OCI) Always Free, you have almost certainly encountered this dreaded error message:

500-InternalError: Out of host capacity for shape VM.Standard.A1.Flex in availability domain...

Oracle’s Always Free tier offers one of the most generous compute allowances in the industry—up to 4 OCPUs and 24 GB RAM on enterprise-grade Ampere Altra ARM64 processors. Because of this, capacity in popular data centers (like Tokyo, Seoul, Ashburn, Frankfurt, and Singapore) is constantly saturated.

Autonomous AI Infrastructure: AnythingLLM, PostgreSQL 18 pgvector, and the Antigravity CLI (agy) System Agent

Mon, 24 Aug 2026 18:43:00 +0700

Most self-hosted AI setups stop at running a basic chat UI connected to a remote API. But what if your self-hosted AI wasn’t just a conversational bot, but a fully empowered autonomous system agent capable of managing your infrastructure, installing command-line tools, debugging services, and querying custom vector databases?

In this post, I will explore our complete self-hosted AI architecture running on an Always Free cloud Kubernetes cluster—featuring AnythingLLM, PostgreSQL 18 with pgvector, and the Google Antigravity CLI (agy).

Architecting a Multi-Node Hybrid K3s Kubernetes Fleet on Oracle Cloud Always Free

Mon, 24 Aug 2026 18:40:00 +0700

How do you turn 3 separate Always Free cloud virtual machines into a resilient, production-grade, multi-architecture Kubernetes cluster capable of running high-performance relational databases, AI vector stores, lossless music streaming, and personal cloud storage?

In this post, I will break down the complete architecture of our newly deployed 3-Node Hybrid K3s Cluster running on Oracle Cloud Infrastructure (OCI) under our custom domain vinhthang.dev.

🏛️ The 3-Node Cluster Topology

Oracle Cloud’s Always Free tier offers an incredible set of compute resources:

🚀 Welcome to my Self-Hosted Cloud on Oracle Always Free

Fri, 21 Aug 2026 00:18:00 +0700

Welcome to my personal tech blog!

This blog is built using Hugo with the PaperMod theme, served directly by Caddy with automatic Let’s Encrypt SSL.

🌐 What is running on this server:

AdGuard Home: Dual-stack network-wide ad & malware blocking (IPv4, IPv6, DoT).
VietCalendar: High-performance Rust Lunar Calendar REST API & MCP Server.
Navidrome: Bit-perfect lossless FLAC music streaming.
FileBrowser: Private cloud storage with Google SSO.
Hugo Blog: Ultra-fast static site serving at sub-millisecond speeds with 0 MB RAM overhead!

Built with ❤️ on Oracle Linux 10 (amd10 in Tokyo).