Devops

DevOps — Infrastructure & Deployment

Ship reliably. Monitor everything. Fix fast.

Deployment Checklist

Before any deploy:

1. All tests pass in CI (not just locally)
2. Environment variables set in target environment
3. Database migrations tested against production-like data
4. Rollback plan documented (even if it's "revert this commit")
5. Health check endpoint exists and returns 200

CI/CD Pipeline

push → lint → typecheck → test → build → deploy staging → smoke test → deploy prod

Docker

Always use multi-stage builds to keep images small. Detect the stack and use the appropriate base image.

Node.js / TypeScript

FROM node:22-alpine AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci --production=false
COPY . .
RUN npm run build

FROM node:22-alpine
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
EXPOSE 3000
CMD ["node", "dist/server.js"]

Python

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 . .
EXPOSE 8000
CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

Go

FROM golang:1.22-alpine AS builder
WORKDIR /app
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -o server ./cmd/api

FROM alpine:3.19
WORKDIR /app
COPY --from=builder /app/server .
EXPOSE 8080
CMD ["./server"]

Ruby on Rails

FROM ruby:3.3-slim AS builder
WORKDIR /app
COPY Gemfile Gemfile.lock ./
RUN bundle install --without development test

FROM ruby:3.3-slim
WORKDIR /app
COPY --from=builder /usr/local/bundle /usr/local/bundle
COPY . .
EXPOSE 3000
CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]

For other stacks (Java/JVM, .NET, Rust): same pattern — build stage compiles, final stage is minimal. Never copy the build toolchain into the final image.

Rules for all stacks:

• Always pin base image versions (not latest)
• Use .dockerignore — never ship build artifacts, .git, or .env files
• One process per container
• Add a health check: HEALTHCHECK CMD curl -f http://localhost:<PORT>/health || exit 1

Monitoring

Rules:

• Every alert must have a runbook (even a one-liner)
• If an alert fires and needs no action, delete it — alert fatigue kills
• Log structured JSON, not printf strings
• Include request ID in every log line for tracing

Infrastructure Defaults

Incident Response

1. Detect — alert fires or user report
2. Acknowledge — someone owns it (within 5 min)
3. Mitigate — rollback, feature flag off, or scale up (fix the bleeding)
4. Investigate — root cause after bleeding stops
5. Fix — proper fix with tests
6. Postmortem — blameless, focus on systems not people