Docker and Docker Compose from simple containers to secure Kubernetes delivery

macOS setup

1. Install Docker Desktop for Mac.
2. Open Docker Desktop and finish the first-run setup.
3. Open Terminal and verify Docker and Compose.

docker --version
docker compose version
docker run hello-world

Windows setup

1. Install Docker Desktop for Windows.
2. Enable WSL 2 integration when prompted.
3. Use PowerShell or Windows Terminal.

docker --version
docker compose version
docker run hello-world
wsl --status

main.go

package main

import (
  "fmt"
  "log"
  "net/http"
  "os"
)

func main() {
  port := getenv("PORT", "8080")
  http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintf(w, "Hello from Go container! host=%s\n", getenv("HOSTNAME", "local"))
  })
  http.HandleFunc("/health", func(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(http.StatusOK)
    fmt.Fprintln(w, "ok")
  })
  log.Fatal(http.ListenAndServe(":"+port, nil))
}

func getenv(k, fallback string) string {
  if v := os.Getenv(k); v != "" { return v }
  return fallback
}

Dockerfile

# syntax=docker/dockerfile:1
FROM golang:1.23-alpine AS build
WORKDIR /src
COPY go.mod ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -o /out/app .

FROM gcr.io/distroless/static-debian12:nonroot
WORKDIR /app
COPY --from=build /out/app /app/app
EXPOSE 8080
USER nonroot:nonroot
ENTRYPOINT ["/app/app"]

Kind cluster

# Install kind, kubectl, and Docker first
kind create cluster --name docker-lab
kubectl cluster-info --context kind-docker-lab

# Build image locally and load it into Kind
docker build -t go-api:kind .
kind load docker-image go-api:kind --name docker-lab

Kubernetes Deployment + Service

apiVersion: apps/v1
kind: Deployment
metadata:
  name: go-api
spec:
  replicas: 3
  selector:
    matchLabels:
      app: go-api
  template:
    metadata:
      labels:
        app: go-api
    spec:
      containers:
        - name: api
          image: go-api:kind
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8080
          readinessProbe:
            httpGet:
              path: /health
              port: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: go-api
spec:
  selector:
    app: go-api
  ports:
    - port: 80
      targetPort: 8080
  type: ClusterIP

Rancher Desktop for local work

Rancher Desktop can run Kubernetes locally and includes container runtime options. It is useful when you want a Docker Desktop alternative or a local Kubernetes environment.

# After installing Rancher Desktop with Kubernetes enabled
kubectl get nodes
kubectl create deployment demo --image=nginx
kubectl expose deployment demo --port=80 --type=ClusterIP

Rancher Manager idea

Rancher Manager is used to manage multiple Kubernetes clusters, users, RBAC, apps, and policies from one interface.

# Lab-only single-node example idea
# For production, follow official HA install guidance.
docker run -d --restart=unless-stopped \
  -p 80:80 -p 443:443 \
  --privileged \
  rancher/rancher:latest