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The failures that cost me the most in three years of self-hosting were never the ones that threw an error. An error is a gift: it tells you where to look. The expensive ones are the failures that report success while being broken . A page that returns 200 OK . A healthcheck that says the container is fine. A backup that exits cleanly. A command that prints nothing wrong. Everything green, everything lying. Here are four of them, all from the same box (a 2016 desktop, i7-6700 / 32 GB, Docker behind Caddy, reachable only over Tailscale). Each fails by handing you a success signal. Each cost me an evening the first time. The fixes are boring once you know them, the point is knowing the failure exists. Sanitized skeleton with all the config at the end. 1. A loading page that returns 200 This one I could find nothing written about, so it cost me the most. To keep the box quiet, I run the heavy services on-demand: Sablier stops idle containers and starts them on the first request. Caddy (with the Sablier plugin) gates a virtual host behind a container group, serves a "please wait, starting up" page while the group boots, then proxies through: myhost . my - tailnet . ts . net : 8081 { route { sablier http :// sablier : 10000 { group office session_duration 30 m } reverse_proxy nextcloud : 80 } } I gate my whole Nextcloud vhost, WebDAV included, this way. And here is the silent failure: if the gated group is not healthy, Sablier serves that HTML loading page for every request, and it serves it with 200 OK . A browser shows a spinner, fine. But my Obsidian vault syncs over WebDAV, and a WebDAV client asking for a directory listing got a 200 with a chunk of HTML instead of the XML it expected. Sync died with a cryptic no root multistatus found . Nextcloud itself was up and perfectly healthy the whole time. Every uptime check I had was green, because the gate in front kept answering 200 . The structural lesson: the moment you put a service on-demand behind a reverse proxy, tha

For 4 years, I lived in the world of IT Operations. My days were spent handling incident response, managing data lifecycles, and making sure systems stayed online. I learned how to troubleshoot under pressure, talk to frustrated users, and keep the business running. But I had a lingering frustration: I was always fixing other people's code. I never got to build it. And more importantly, I was fixing problems manually that I knew could be automated. So, I decided to make a massive pivot. I went back to university (VILNIUS TECH) and recently started a Java Engineering internship at Coherent Solutions. My goal isn't just to become a Java developer. My goal is to bridge the gap between Development and Operations- DevOps . In my first few weeks at Coherent, we started learning about enterprise architecture. But the moment that truly clicked for me was when I built my first Docker image for our project. In my past IT life, deploying an app was a nightmare. "It works on my machine!" was a constant joke (and a constant headache for the Ops team). Setting up environments, installing the right Java version, configuring databases—it was manual, error-prone, and boring. Then I wrote a Dockerfile . I packaged our Java application and its dependencies into a single, isolated container. Suddenly, I realized: This is how you solve the "works on my machine" problem forever. As someone who used to be the guy manually fixing those environment issues, writing a few lines of code to completely automate that process felt like a superpower. I'm starting this blog to document my journey in real-time. I'm currently diving deep into: 🔹 Java 21 (the newest LTS—highly recommend checking out Virtual Threads!) 🔹 Spring Boot & enterprise backend architecture 🔹 Docker & containerization 🔹 Next up: CI/CD pipelines and Infrastructure as Code (Terraform) If you are currently stuck in IT Support or SysAdmin roles and dreaming of becoming a DevOps or Software Engineer—you aren't alone. Let's learn toge

A container's writable layer feels like a filesystem, and that's exactly the trap. Write a database into it, remove the container, and the data is gone — no warning, no recovery. If you want anything to survive docker rm , it has to live outside the container, and Docker gives you three ways to do that: named volumes, bind mounts, and tmpfs. Knowing which one to reach for is most of the battle. Why the writable layer betrays you Every running container gets a thin read-write layer stacked on top of its image layers. It looks persistent because you can docker exec in and see your files. But that layer is bound to the container's lifecycle. docker run --name scratch alpine sh -c 'echo hello > /data.txt; cat /data.txt' # hello docker rm scratch # the layer — and /data.txt — no longer exists There's no "oops." The writable layer is discarded with the container. Persistence is not a default you get; it's a decision you make. That decision is a volume, a bind mount, or tmpfs. Named volumes: the default for state A named volume is storage that Docker creates and manages for you. You give it a name, Docker keeps the actual bytes under its own directory, and you never have to care where that is. docker volume create pgdata docker run -d --name db \ --mount type = volume,source = pgdata,target = /var/lib/postgresql/data \ postgres:16 The container writes to /var/lib/postgresql/data , but those bytes land in a Docker-managed location on the host. Remove and recreate the container against the same volume and the data is still there. docker rm -f db docker run -d --name db \ --mount type = volume,source = pgdata,target = /var/lib/postgresql/data \ postgres:16 # same data, new container Where do the bytes actually live? Under Docker's data root, typically /var/lib/docker/volumes/<name>/_data : docker volume inspect pgdata --format '{{ .Mountpoint }}' # /var/lib/docker/volumes/pgdata/_data The point is that you're not supposed to reach into that path directly — Docker owns it. You

Quando voce cria um container e depois outro, eles podem nao se enxergar. O motivo quase sempre e a rede. Entender os tipos de rede que o Docker oferece resolve isso de uma vez. Comece listando as redes que ja existem no seu Docker. docker network ls A rede bridge e a rede host vem de fabrica. Nenhuma delas oferece resolucao de nomes entre containers. Para isso voce precisa criar a sua propria rede. docker network create minha-rede Agora os containers que entrarem nessa rede conseguem se comunicar pelo nome do container. docker run -d --name app1 --network minha-rede nginx docker run -d --name app2 --network minha-rede alpine sleep 3600 Teste a comunicacao. docker exec app2 ping app1 -c 2 O ping funciona. O DNS interno do Docker resolve app1 para o IP interno do container. Isso resolve 90% dos problemas de comunicacao. A rede bridge padrao nao tem esse recurso. Crie sua propria rede sempre que precisar que containers se enxerguem. Agora a rede host. Ela elimina o isolamento de rede. O container usa a placa do host diretamente, sem NAT e sem mapeamento de porta. docker run -d --name web-host --network host nginx O nginx fica acessivel em http://localhost:80 direto. Sem -p 80:80. Mas so um container pode usar cada porta, porque a porta e a do host de verdade. Para ambientes com mais de uma maquina, existe a rede overlay. Ela precisa do Docker Swarm ou de um cluster. docker swarm init docker network create -d overlay rede-overlay docker service create --name api --network rede-overlay --replicas 3 nginx Os containers em maquinas diferentes se enxergam pelo nome como se estivessem na mesma maquina. No dia a dia, a rede bridge personalizada resolve quase todo caso de uso. Host e para performance ou casos especificos. Overlay e para quando voce escala para mais de uma maquina. That's all for now. Thanks for reading!

Yes, you heard it right, you can now run a Dockerfile on Vercel. Vercel was the go-to place where...

Most Dockerfiles work. That's the problem — "it builds and runs" hides a lot of quiet costs in security, speed, and size that don't announce themselves until an audit, an incident, or a cloud bill does it for them. Here are seven mistakes I see constantly, and what to do instead. 1. Running as root By default, the process in your container runs as root — and if someone breaks out, they're root on a surface they shouldn't be. Add a non-root user and switch to it: RUN useradd --system --uid 10001 appuser USER appuser Cheap, and it closes off a whole category of "well, at least it wasn't root" incidents. 2. FROM some-image:latest latest is not a version — it's "whatever was newest when this happened to build." Two builds a week apart can produce different images with no diff to explain it, and a surprise base upgrade is a fun way to spend a Friday. Pin a specific tag, ideally by digest: FROM node:20.11.1-slim 3. Baking secrets into layers COPY .env . or ARG API_KEY followed by using it — and now the secret lives in an image layer forever , recoverable by anyone who pulls the image, even if a later layer deletes the file. Layers are immutable and additive; you can't delete your way out of a leak. Use build secrets ( --mount=type=secret ) or inject at runtime, never at build. 4. No .dockerignore Without one, COPY . . sweeps your .git directory, local env files, node_modules , and test data into the build context — bloating the image and, worse, potentially baking credentials and history into a layer. A five-line .dockerignore is one of the highest-leverage files in the repo. 5. Layer order that destroys your cache COPY . . RUN npm ci # ← reinstalls on EVERY code change Docker invalidates every layer after the first change. Copy the lockfile and install dependencies before copying the rest of your source, so a one-line code change doesn't trigger a full reinstall. This is a build-speed bug hiding as a style choice. 6. Leaving package manager cruft in the image RUN apt-get

Bạn sẽ học gì Sau bài này, bạn sẽ tự tay đưa một app từ số 0 (một thư mục trống) đến chạy được bên trong một cluster Kubernetes chạy trên máy của bạn . Cụ thể: Viết một app Todo API nhỏ bằng Node.js + Express. Đóng gói (container hoá) nó thành một Docker image. Tạo một cluster Kubernetes local bằng kind . Deploy app bằng file YAML "thật" (không dùng lệnh tắt) để hiểu Kubernetes vận hành thế nào. Truy cập app đang chạy trong cluster từ máy của bạn. Đây là Part 1 trong series "DevOps 101 — Học K8s, Helm, ArgoCD từ số 0" . Cả series dùng chung một app tên todo-ops , các part sau sẽ xây tiếp lên nền này (thêm database, config, ingress, Helm, GitOps với ArgoCD). Điều kiện tiên quyết Docker (hoặc Docker Desktop / OrbStack) — đang chạy. kind — công cụ tạo cluster Kubernetes trong Docker. kubectl — CLI để nói chuyện với Kubernetes. Node.js 20+ và npm — để chạy thử app local. git — để quản lý mã nguồn. Cài đặt Chọn theo hệ điều hành của bạn. macOS (dùng Homebrew — nếu chưa có, cài trước): # Cài Homebrew (bỏ qua nếu đã có) /bin/bash -c " $( curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh ) " # Docker Desktop (hoặc OrbStack: brew install --cask orbstack) brew install --cask docker # Các CLI còn lại brew install kind kubectl node git Sau khi cài xong, mở Docker Desktop (hoặc OrbStack) và chờ nó báo Running trước khi chạy tiếp. Linux (Ubuntu/Debian): # Docker Engine curl -fsSL https://get.docker.com | sh sudo usermod -aG docker " $USER " # cho phép chạy docker không cần sudo (đăng xuất/đăng nhập lại để có hiệu lực) # kubectl curl -LO "https://dl.k8s.io/release/ $( curl -Ls https://dl.k8s.io/release/stable.txt ) /bin/linux/amd64/kubectl" sudo install -m 0755 kubectl /usr/local/bin/kubectl && rm kubectl # kind curl -Lo ./kind https://kind.sigs.k8s.io/dl/latest/kind-linux-amd64 sudo install -m 0755 kind /usr/local/bin/kind && rm kind # Node.js 20 (qua NodeSource) + git curl -fsSL https://deb.nodesource.com/setup_20.x | sudo -E bash - sudo apt-get insta

Azure Storage SFTP is Microsoft's managed file transfer service on top of Azure Blob Storage, convenient, but billed continuously per endpoint (roughly $0.30/hour, ~$220/month) and tied to Azure AD. SFTPGo is an open-source file transfer server offering SFTP, FTP/S, and WebDAV with pluggable storage backends (local disk, Azure Blob, S3-compatible, GCS) and no per-endpoint charge. This guide deploys SFTPGo with Docker Compose and Traefik, sets up user auth (password + SSH key + 2FA), connects S3-compatible object storage, and covers the migration path from Azure Storage SFTP. By the end, you'll have a self-hosted file transfer server with the same capabilities at zero endpoint cost. Azure Storage SFTP → SFTPGo Mapping Azure Storage SFTP SFTPGo Equivalent Notes SFTP Endpoint SFTPGo SFTP Server Configurable port, default 2022 Azure Blob Storage Azure Blob backend Native support; point at the same container, no migration needed Azure AD Authentication LDAP/OIDC plugin External identity provider via plugin Local Users Web UI / REST API user management Hierarchical Namespace Virtual directories No HNS requirement Azure Monitor Built-in logging + webhooks/syslog Prerequisite: Linux server with Docker + Compose, a DNS A record for your domain, and (if migrating) an existing Azure Storage account with SFTP enabled plus the Azure CLI installed locally. Deploy with Docker Compose 1. Create the project directories: $ mkdir -p ~/sftpgo/ { data,config } $ cd ~/sftpgo 2. Create the environment file: $ nano .env DOMAIN = sftp.example.com LETSENCRYPT_EMAIL = admin@example.com 3. Create the Compose manifest: $ nano docker-compose.yml services : traefik : image : traefik:v3.6 container_name : traefik command : - " --providers.docker=true" - " --providers.docker.exposedbydefault=false" - " --entrypoints.web.address=:80" - " --entrypoints.websecure.address=:443" - " --entrypoints.web.http.redirections.entrypoint.to=websecure" - " --certificatesresolvers.letsencrypt.acme.httpchallenge=tr

Google Vertex AI is Google Cloud's managed ML platform with experiment tracking, training jobs, pipelines, a model registry, and endpoints, but it locks you into GCP-specific APIs and per-use billing. ClearML is an open-source MLOps platform that covers the same ground on any Docker host or Kubernetes cluster, capturing training metrics automatically with no code changes and keeping every byte of data on infrastructure you control. This guide deploys ClearML Server with Docker Compose and Traefik, registers an agent, runs an experiment, builds a pipeline, runs a hyperparameter sweep, and deploys a Triton-served model. By the end, you'll have a self-hosted Vertex AI replacement covering the full ML lifecycle. Vertex AI → ClearML Mapping GCP Vertex AI ClearML Equivalent Purpose Vertex AI Workbench ClearML Web UI Browser-based monitoring and configuration Vertex AI Experiments ClearML Experiment Manager Automatic hyperparameter/metric/artifact tracking Vertex AI Training Job ClearML Agent + Tasks Any machine becomes a remote worker via queues Vertex AI Pipelines ClearML Pipelines Python-native DAGs, no separate compile step Vertex AI Model Registry ClearML Model Repository Versioned models with full lineage Vertex AI Endpoints ClearML Serving (Triton) Self-hosted inference with canary/A-B support Cloud Monitoring/Logging ClearML Scalars/Plots Built-in metrics and hardware dashboards Prerequisite: Ubuntu host with Docker + Compose, DNS A records for app.clearml.example.com , api.clearml.example.com , files.clearml.example.com . NVIDIA Container Toolkit if you'll run GPU agents. Deploy the ClearML Server 1. Raise Elasticsearch's virtual memory limit and restart Docker: $ echo "vm.max_map_count=524288" | sudo tee /etc/sysctl.d/99-clearml.conf $ sudo sysctl --system $ sudo systemctl restart docker 2. Create persistent data directories with the correct ownership: $ sudo mkdir -p /opt/clearml/ { data/elastic_7,data/mongo_4/db,data/mongo_4/configdb,data/redis,data/fileserver,

Matomo is an open-source web analytics platform that keeps full ownership of visitor data on infrastructure you control, a privacy-first alternative to Google Analytics. This guide deploys Matomo using Docker Compose with a MariaDB backend, Nginx as the entry point, and Certbot issuing the TLS certificate before the stack goes live. By the end, you'll have Matomo tracking a website with a signed HTTPS certificate at your domain. Prepare Docker $ sudo usermod -aG docker $USER $ newgrp docker Set Up the Project 1. Create the project directory: $ mkdir matomo && cd matomo 2. Open the firewall: $ sudo ufw allow 80/tcp $ sudo ufw allow 443/tcp 3. Create the environment file: $ nano .env MYSQL_ROOT_PASSWORD = your_strong_mysql_root_password MYSQL_PASSWORD = your_strong_mysql_matomo_password Use passwords of at least 16 characters. 4. Create the Nginx config: $ mkdir nginx $ nano nginx/matomo.conf server { listen 80 ; server_name matomo.example.com ; location /.well-known/acme-challenge/ { root /var/www/certbot ; } location / { return 301 https:// $host$request_uri ; } } server { listen 443 ssl http2 ; server_name matomo.example.com ; ssl_certificate /etc/letsencrypt/live/matomo.example.com/fullchain.pem ; ssl_certificate_key /etc/letsencrypt/live/matomo.example.com/privkey.pem ; location / { proxy_pass http://app:80 ; proxy_set_header Host $host ; proxy_set_header X-Real-IP $remote_addr ; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for ; proxy_set_header X-Forwarded-Proto $scheme ; } } Replace every matomo.example.com occurrence with your domain — it appears in both server blocks and the certificate paths. Deploy with Docker Compose $ nano docker-compose.yaml services : db : image : mariadb:11.4 command : --max-allowed-packet=64MB restart : always volumes : - matomo-db-data:/var/lib/mysql environment : - MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD} - MYSQL_DATABASE=matomo - MYSQL_USER=matomo - MYSQL_PASSWORD=${MYSQL_PASSWORD} networks : - matomo-net app : image

Plausible Analytics is an open-source, self-hosted web analytics tool that tracks traffic without cookies or personal data collection, a privacy-first alternative to Google Analytics. This guide deploys Plausible Community Edition using Docker Compose, fronts it with Nginx, and secures it with a Let's Encrypt certificate. By the end, you'll have Plausible tracking a website's traffic securely at your domain. Configure the Environment 1. Clone the Community Edition repo: $ mkdir ~/plausible $ cd ~/plausible $ git clone https://github.com/plausible/community-edition.git $ cd community-edition 2. Generate a secret key: $ openssl rand -base64 64 | tr -d '\n' 3. Create the environment file: $ nano .env ADMIN_USER_EMAIL = admin@example.com ADMIN_USER_NAME = admin ADMIN_USER_PWD = ADMIN_PASSWORD BASE_URL = https://plausible.example.com SECRET_KEY_BASE = YOUR_SECRET_KEY_BASE DATABASE_URL = postgres://postgres:postgres@plausible_db:5432/plausible_db CLICKHOUSE_DATABASE_URL = http://plausible_events_db:8123/plausible_events_db Fill in your email, a strong admin password, your domain, and the secret key generated above. 4. Expose the app port via a Compose override (auto-merged with compose.yml ): $ nano compose.override.yaml services : plausible : ports : - 127.0.0.1:8000:8000 Deploy with Docker Compose $ docker compose up -d $ docker compose ps Confirm the app, Postgres, and ClickHouse (events DB) containers are all running. Front with Nginx and Let's Encrypt 1. Install Nginx: $ sudo apt update $ sudo apt install nginx -y 2. Create the virtual host: $ sudo nano /etc/nginx/sites-available/plausible.conf server { listen 80 ; listen [::]:80 ; server_name plausible.example.com ; access_log /var/log/nginx/plausible.access.log ; error_log /var/log/nginx/plausible.error.log ; location / { proxy_pass http://127.0.0.1:8000 ; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for ; proxy_http_version 1.1 ; proxy_set_header Upgrade $http_upgrade ; proxy_set_header Connection "Upgr

One-Command Deployment: Self-Host Your AI Wallet with Docker and GHCR Would you trust a third party with your AI agent's private keys? If that question makes you uncomfortable, you're already thinking about self-hosting your wallet infrastructure — and WAIaaS makes it genuinely practical with a single Docker command. This post walks through how to get a fully self-hosted Wallet-as-a-Service running on your own server, with your own keys, under your own rules. Why Self-Hosting Your AI Wallet Actually Matters The rise of autonomous AI agents changes the stakes around custody. When a human manages a wallet, they can pause, verify, and think before signing. An AI agent operates continuously, potentially making hundreds of transactions — so the infrastructure holding those keys becomes critically important. Hosted wallet services make a trade-off: you get convenience in exchange for trusting someone else's server, someone else's rate limits, and someone else's uptime SLA. For many teams building experimental agents, that's fine. But for anyone running production workloads, handling real funds, or operating in environments with strict data residency requirements, the calculus shifts. Self-hosting gives you: Full key custody — private keys never leave your infrastructure No rate limits imposed by a third party — your server, your throughput Auditability — WAIaaS is open-source, so you can read every line of code handling your keys Network control — bind to localhost, put it behind a VPN, restrict egress however you want WAIaaS is built specifically for this use case: a self-hosted, open-source Wallet-as-a-Service designed for AI agents, deployable in one command. The One-Command Start The Docker image is published to GitHub Container Registry (GHCR) at ghcr.io/minhoyoo-iotrust/waiaas:latest . The fastest path to a running instance is: git clone https://github.com/minhoyoo-iotrust/WAIaaS.git cd WAIaaS docker compose up -d That's it. The daemon starts on port 3100 , bound to

Multi stage builds sao uma das melhores features do Docker para manter imagens pequenas e organizadas. Vou mostrar como aplicar isso em um projeto Python real. Crie um arquivo app.py simples: # app.py def main(): print("Hello from a multi stage build") if __name__ == "__main__": main() Agora crie o Dockerfile sem multi stage: FROM python:3.12-slim WORKDIR /app COPY requirements.txt . RUN pip install --no-cache-dir -r requirements.txt COPY . . CMD ["python", "app.py"] Essa imagem inclui o pip, o cache do pip e ferramentas de build que nao precisamos em producao. O resultado e uma imagem maior que o necessario. Com multi stage builds separamos o ambiente de build do ambiente final. Veja o mesmo Dockerfile com dois stages: FROM python:3.12-slim AS builder WORKDIR /app COPY requirements.txt . RUN pip install --no-cache-dir -r requirements.txt FROM python:3.12-slim WORKDIR /app COPY --from=builder /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages COPY . . CMD ["python", "app.py"] O primeiro stage instala as dependencias. O segundo stage copia so o que importa. O resultado e uma imagem final muito menor. Para construir e ver o tamanho: docker build -t minha-app . docker images | grep minha-app Para linguagens compiladas como Go o ganho e ainda maior. Veja um exemplo com uma aplicacao Go: FROM golang:1.23 AS builder WORKDIR /app COPY go.mod go.sum ./ RUN go mod download COPY . . RUN CGO_ENABLED=0 GOOS=linux go build -o /app/server FROM scratch COPY --from=builder /app/server /server CMD ["/server"] A imagem final comeca do zero (scratch). Nao tem shell, sistema operacional, nem ferramentas de build. So o binario compilado. Uma dica pratica: sempre nomeie seus stages com AS para facilitar a leitura. Use nomes como builder, test, ou dev. Isso ajuda a saber o que cada stage faz sem precisar contar linhas. That's all for now. Thanks for reading!

Developers love building things. Sometimes the hardest part isn't writing code—it's organizing data. Over the past few months, I've been building a large SVG library containing more than 180,000 vector files. At first, I assumed collecting the files would be the biggest challenge. I was wrong. The real challenge was organizing them. The Duplicate Problem Once a collection reaches hundreds of thousands of files, duplicates become unavoidable. Different sources often contain identical icons with different filenames. For example: facebook.svg facebook-logo.svg facebook-icon.svg facebook-black.svg facebook-circle.svg Some of these are genuine variations. Others are simply duplicates from different icon packs. Automatically detecting the difference isn't always easy. Collections Instead of Files Instead of treating every SVG as an individual page, I decided to build everything around collections. Examples include: Facebook Docker Kubernetes Payment Icons Weather Icons Medical Icons Programming Languages Each collection groups similar SVGs together, making browsing much easier than searching individual files. Keeping Search Engines Happy One interesting problem appeared during development. Should every individual SVG page be indexed? After experimenting with different structures, I chose a different approach. Only complete, content-rich collections are indexed. Individual SVG pages remain accessible but are excluded from search engine indexes. This avoids creating hundreds of thousands of thin pages while allowing search engines to focus on pages that actually provide value. Automation Managing thousands of collections manually isn't realistic. Several background scripts now automate most repetitive tasks: Collection descriptions Meta titles Meta descriptions FAQ generation Sitemap updates Controlled indexing This allows the library to continue growing without requiring manual editing for every collection. Data Cleanup One task I underestimated was cleanup. Large datasets

I have a folder on my laptop called side-projects . Most of them are Dockerized. Most of them will never see more than a handful of users. And for years, every one of them hit the same wall: getting the thing onto a cheap VPS without losing a weekend — and copy-pasting my own past mistakes forward every single time. Here's the opinion that eventually turned into a project: the part of a PaaS you touch most often should hold the least power over your server. Think of a deploy tool as two planes. There's a read plane — dashboards, logs, container health, the stuff you stare at — where you spend most of your time and which is your most exposed surface. And there's a write plane — deploy, restart, the actions that actually change the system — which is rare and should be gated. My frustration was that the thing I looked at all day and the thing that could rewrite my box tended to sit on the same pile of privilege. So I built Mooring to keep those two planes apart. It's an early, solo project, and this post is me showing it and asking for eyes on it. The mental model The whole thing, end to end: Install it as an unprivileged systemd service (not root). Connect a git repo. Write one mooring.yaml . Click Deploy. That's the loop. Everything below is what's underneath it. What it is Mooring is a small, security-first, self-hosted control plane for Docker — a tiny PaaS. You point it at a git repo, describe your app once, and it deploys and runs your containers on your own server. Same territory as Coolify, Dokku, CapRover, and Kamal — all genuinely good work. The difference I care about is the posture underneath. It ships as one static, CGO-free Go binary . It runs as an unprivileged systemd service — not root. State lives in SQLite (the pure-Go modernc driver). Every asset is embedded with go:embed , so there's no node_modules , no asset pipeline, nothing to build on the box. To be honest about the neighborhood: setting up a self-hosted PaaS, these tools tend to want broad ac

"Docker vs Kubernetes" is one of those framings that quietly sends people down the wrong road. It sounds like a choice between two competing tools, so teams treat it like a bake-off. It isn't. Docker builds and runs containers. Kubernetes orchestrates a fleet of them. You can happily use one without the other, and most teams should — at least for a while. The question that actually matters is hiding underneath: do I need an orchestrator yet? That's the one worth thinking about carefully, because the cost of answering "yes" too early is real, and it mostly shows up later, on a Saturday, when you're the one holding the pager. What each tool actually does Let me separate the two cleanly, because the confusion causes most of the bad decisions. Docker (or any OCI-compatible runtime — Podman, containerd, and friends) does two jobs: it builds an image from a Dockerfile , and it runs that image as a container on a host. That's the unit of packaging. When you type this: docker build -t registry.example.com/myapp:1.4.2 . docker run -d -p 8080:8080 registry.example.com/myapp:1.4.2 you've packaged your app and started it on one machine . If that machine dies, your app dies with it. If you need three copies, you start three by hand. If you push a bad image, you roll it back by hand. Kubernetes doesn't build or run containers itself — it schedules them across a set of machines and keeps them in the state you declared. You tell it "I want three replicas of myapp:1.4.2 , behind a stable network name, and if a node dies, reschedule them." Kubernetes then spends its life making reality match that declaration. So they're not competitors. Kubernetes runs your Docker-built images. The real comparison isn't "Docker vs Kubernetes" — it's "a couple of containers on a host I manage" versus "a control plane that manages containers for me." A small, honest comparison Concern Plain Docker (or Compose) Kubernetes Where it runs One host you manage A cluster of nodes If a node dies You notice and

If you're comfortable with docker compose up , you already understand more of Kubernetes than you think. Compose taught you to describe an application declaratively — services, their images, their config, how they talk to each other — instead of running containers by hand. Kubernetes is the same instinct, scaled out across a cluster, with more moving parts because it's solving a harder problem: keeping that application running when machines fail. The good news is the mental model transfers. The honest news is that the operational surface grows, and it's worth knowing exactly what changes before you commit. Let me map the concepts you already know onto their Kubernetes equivalents, show the YAML side by side, and be straight about the parts that get harder. First, the thing that doesn't change: your images This trips people up, so let's clear it early. The Docker images you already build run on Kubernetes unmodified. Kubernetes doesn't use the Docker daemon to run them — most clusters use containerd or CRI-O — but every one of those runtimes runs standard OCI images. That's the whole point of the OCI standard: the image you built with docker build is the same artifact the cluster pulls and runs. docker build -t registry.example.com/myapp:1.4.2 . docker push registry.example.com/myapp:1.4.2 That image works identically whether docker run starts it or a Kubernetes node's containerd does. So the packaging is settled. What changes is everything around the container. The concept map Here's the translation table I'd keep next to you while you learn: Docker Compose Kubernetes What changed service Deployment + Service Running vs. reachable are now two objects image: spec.containers[].image Same OCI image ports: Service (+ Ingress for external) Networking is explicit and named depends_on: probes / initContainers Ordering becomes health, not sequence environment: / .env ConfigMap / Secret Config decoupled from the pod volumes: PersistentVolume / PVC Storage is claimed, not jus

"Works on my machine" is one of the oldest jokes in software, and it stopped being funny the first time it cost me a weekend. The code was fine. The environment wasn't. A library version on the build box didn't match production, and nobody could see it because "the environment" was a fuzzy, undocumented thing that lived partly in a config management tool, partly in someone's .bashrc , and partly in tribal memory. Containerization is the boring, durable fix for that whole class of problem. Not because containers are magic, but because they force you to turn a fuzzy environment into a single, inspectable, reproducible artifact. That shift — from "a machine we hope is configured right" to "an image we can point at" — is the actual win. Let me walk through what that means operationally, with a minimal example. What containerization actually solves Strip away the tooling and a container image is one thing: your application plus everything it needs to run, packaged together and frozen. The OS libraries, the runtime, the dependencies, your code — all captured at build time into one immutable blob with a content-addressable identity. That has three consequences that matter when you're the one on call: The environment stops being a variable. If it runs from image myapp:1.4.2 in staging, the same image runs in production. You're no longer debugging the difference between two machines. The artifact is immutable. You don't patch a running container in place and hope. You build a new image, tag it, and roll it out. The old one still exists, unchanged, if you need to go back. Rollback becomes trivial. "Roll back" means "run the previous image tag." That's it. No reinstalling packages, no un-applying config drift. After enough years in operations, you learn that most 3 a.m. incidents aren't exotic. They're some version of "this box isn't like the other boxes." Containers don't make you smarter, but they take that entire category off the table. Images vs. containers, briefly These

I just shipped 5 new tools to DevNestio — a hub of 172 free, browser-only developer utilities. All tools are zero-signup, zero-upload, and work offline. 1. GraphQL Query Formatter & Minifier https://devnestio.pages.dev/graphql-formatter/ Paste any GraphQL operation and get: Pretty-print — consistent indentation Minify — strips comments and whitespace for smaller request payloads Validation — brace/parenthesis balance check Operation detection — lists all named query , mutation , subscription , fragment Useful for quick query cleanup before pasting into code reviews or API docs. 2. Protobuf (.proto) Formatter & Validator https://devnestio.pages.dev/protobuf-formatter/ Online formatter and validator for Protocol Buffer .proto files: Duplicate field number detection Message and enum structure validation Syntax-highlighted output One-click copy Great for a sanity check before pushing .proto changes in a gRPC service. 3. Docker Compose Validator https://devnestio.pages.dev/docker-compose-validator/ Paste your docker-compose.yml to catch: Missing services section Services without image or build Invalid port mappings ( 80:80 , 127.0.0.1:8080:80 , 53:53/udp , ranges…) depends_on referencing non-existent services Circular dependency detection (A→B→A) Unknown restart policies # This will flag errors: services : web : ports : - " abc:xyz" # invalid port depends_on : - missing_service # unknown service 4. Dockerfile Analyzer & Linter https://devnestio.pages.dev/dockerfile-analyzer/ Analyzes your Dockerfile for best practice violations across three categories: Security sudo usage inside RUN Container running as root (no USER instruction) Secrets baked into ENV / ARG (password, secret, token, key) Image size :latest base image tag apt-get update in a separate RUN (stale cache risk) apt-get install without --no-install-recommends apt cache not cleaned ( rm -rf /var/lib/apt/lists/* ) ADD used for local files instead of COPY Layer optimization Consecutive RUN instructions (suggest c

I had just aced my mentor’s Docker exam, so of course I thought I understood containers. I had said all the right words: namespaces, cgroups, images, layers, PID 1, Kubernetes Pods. Then I typed my first serious command and Linux reminded me that knowing the nouns is not the same thing as building the thing. $ sudo unshare -p 1 test unshare: failed to execute 1: No such file or directory That was the opening scene. I had not even built anything yet. I had typed the flags wrong and accidentally asked unshare to execute a program called 1 . This was going to be less “implement Docker” and more “let the kernel correct my confidence, one error at a time.” v1: namespaces, or the first time PID 1 lied to me The first version was supposed to be easy: run a process in a new PID namespace and prove it sees itself as PID 1. So I ran the command the way I thought it worked: $ sudo unshare --pid bash # echo $$ 25184 That was not PID 1. That was just embarrassing. The rule I had missed is simple: PID namespaces apply to children. The process that calls unshare --pid does not magically become PID 1. You need to fork. The first child born into the new namespace becomes PID 1. So the working version was: $ sudo unshare --pid --fork bash # echo $$ 1 That one line changed the tone. I was inside a different process universe. The shell thought it was process 1. Signals felt different. Orphans came home to it. Then I ran ps , and got humbled again. # ps -o pid,ppid,comm PID PPID COMMAND 25310 25304 bash 25344 25310 ps That made no sense at first. I was PID 1, but ps was showing host-looking PIDs. The next reveal: ps does not ask the kernel some pure “what processes exist?” question. It reads files. If /proc still points at the host procfs, your tools will tell you the host story. So I remounted /proc from inside the namespace: # mount -t proc proc /proc # ps -o pid,ppid,comm PID PPID COMMAND 1 0 bash 7 1 ps That was when it clicked. The namespace did not become real to my eyes until /pr