1 
2Binago ng Docker ang paraan ng pagbuo, pagpapadala, at pagpapatakbo natin ng software. Sa halip na "gumagana sa makina ko," ginagarantiya ng Docker na pareho ang takbo ng iyong application kahit saan - sa iyong laptop, sa makina ng katrabaho, sa CI/CD, at sa production. Sa gabay na ito, magsisimula tayo mula sa zero hanggang sa pag-deploy ng isang tunay na application.
3 
4## Ano ang Docker?
5 
6Ang Docker ay isang platform na nagpa-package ng iyong application at lahat ng dependencies nito sa isang standardized unit na tinatawag na **container**. Ang container ay isang isolated, magaan na proseso na nagbabahagi ng host OS kernel ngunit may sariling filesystem, network, at process space.
7 
8```mermaid
9graph TD
10    subgraph "Traditional Deployment"
11        A1[App 1] --> OS1[Guest OS]
12        A2[App 2] --> OS2[Guest OS]
13        OS1 --> HV[Hypervisor]
14        OS2 --> HV
15        HV --> HW1[Hardware]
16    end
17 
18    subgraph "Docker Deployment"
19        B1[App 1] --> D1[Container]
20        B2[App 2] --> D2[Container]
21        D1 --> DE[Docker Engine]
22        D2 --> DE
23        DE --> HW2[Hardware]
24    end
25```
26 
27### Mga Container vs Virtual Machine
28 
29| Aspeto | Mga Container | Virtual Machine |
30|--------|-------------|-----------------|
31| **Startup** | Segundo | Minuto |
32| **Laki** | MB | GB |
33| **OS** | Nagbabahagi ng host kernel | Buong guest OS |
34| **Isolation** | Antas ng proseso | Antas ng hardware |
35| **Performance** | Halos native | Overhead mula sa hypervisor |
36| **Density** | Daan-daan bawat host | Sampu-sampu bawat host |
37 
38## Pag-install ng Docker
39 
40```bash
41# macOS
42brew install --cask docker
43 
44# Ubuntu/Debian
45curl -fsSL https://get.docker.com | sh
46sudo usermod -aG docker $USER
47 
48# Verify installation
49docker --version
50docker run hello-world
51```
52 
53## Mga Pangunahing Konsepto
54 
55### Mga Image
56 
57Ang image ay isang read-only template na may mga tagubilin para sa paggawa ng container. Isipin ito bilang isang snapshot ng iyong application at ng kapaligiran nito.
58 
59```bash
60# Pull an image from Docker Hub
61docker pull node:20-alpine
62 
63# List local images
64docker images
65 
66# Remove an image
67docker rmi node:20-alpine
68```
69 
70### Mga Container
71 
72Ang container ay isang tumatakbo na instance ng isang image. Maaari kang gumawa, mag-start, mag-stop, at mag-delete ng mga container.
73 
74```bash
75# Run a container
76docker run -d --name my-app -p 3000:3000 node:20-alpine
77 
78# List running containers
79docker ps
80 
81# List all containers (including stopped)
82docker ps -a
83 
84# Stop a container
85docker stop my-app
86 
87# Remove a container
88docker rm my-app
89 
90# View logs
91docker logs my-app
92 
93# Execute a command inside a running container
94docker exec -it my-app sh
95```
96 
97## Pagsulat ng Dockerfile
98 
99Ang Dockerfile ay isang text file na may mga tagubilin para sa pagbuo ng image. Bawat tagubilin ay gumagawa ng isang layer.
100 
101### Basic na Dockerfile para sa isang Node.js App
102 
103```dockerfile
104# Use an official Node.js runtime as base image
105FROM node:20-alpine
106 
107# Set working directory
108WORKDIR /app
109 
110# Copy package files first (better caching)
111COPY package.json package-lock.json ./
112 
113# Install dependencies
114RUN npm ci --only=production
115 
116# Copy application code
117COPY . .
118 
119# Expose the port the app runs on
120EXPOSE 3000
121 
122# Command to run the application
123CMD ["node", "server.js"]
124```
125 
126### Pagbuo at Pagpapatakbo
127 
128```bash
129# Build the image
130docker build -t my-node-app .
131 
132# Run the container
133docker run -d -p 3000:3000 my-node-app
134 
135# Visit http://localhost:3000
136```
137 
138## Multi-Stage Build
139 
140Ang mga multi-stage build ay nagpapanatiling maliit ng iyong production image sa pamamagitan ng paghihiwalay ng build environment mula sa runtime.
141 
142```dockerfile
143# Stage 1: Build
144FROM node:20-alpine AS builder
145WORKDIR /app
146COPY package.json package-lock.json ./
147RUN npm ci
148COPY . .
149RUN npm run build
150 
151# Stage 2: Production
152FROM node:20-alpine AS runner
153WORKDIR /app
154COPY --from=builder /app/dist ./dist
155COPY --from=builder /app/node_modules ./node_modules
156COPY --from=builder /app/package.json ./
157EXPOSE 3000
158CMD ["node", "dist/server.js"]
159```
160 
161Gumagawa ito ng image na naglalaman lamang ng compiled output at production dependencies - walang source code, walang dev dependencies, walang build tools.
162 
163### Next.js Multi-Stage Halimbawa
164 
165```dockerfile
166FROM node:20-alpine AS deps
167WORKDIR /app
168COPY package.json package-lock.json ./
169RUN npm ci
170 
171FROM node:20-alpine AS builder
172WORKDIR /app
173COPY --from=deps /app/node_modules ./node_modules
174COPY . .
175RUN npm run build
176 
177FROM node:20-alpine AS runner
178WORKDIR /app
179ENV NODE_ENV=production
180COPY --from=builder /app/public ./public
181COPY --from=builder /app/.next/standalone ./
182COPY --from=builder /app/.next/static ./.next/static
183EXPOSE 3000
184CMD ["node", "server.js"]
185```
186 
187## Mga Volume: Persistent na Data
188 
189Bilang default, nawawala ang data sa loob ng container kapag inalis ang container. Nilulutas ito ng mga volume.
190 
191```bash
192# Create a named volume
193docker volume create my-data
194 
195# Run with a volume
196docker run -d -v my-data:/app/data my-app
197 
198# Bind mount (map host directory to container)
199docker run -d -v $(pwd)/data:/app/data my-app
200 
201# List volumes
202docker volume ls
203```
204 
205## Networking
206 
207Gumagawa ang Docker ng mga isolated network para makipag-usap ang mga container.
208 
209```bash
210# Create a custom network
211docker network create my-network
212 
213# Run containers on the same network
214docker run -d --name api --network my-network my-api
215docker run -d --name db --network my-network postgres:16
216 
217# Containers can reach each other by name
218# From "api" container: postgres://db:5432
219```
220 
221```mermaid
222graph LR
223    subgraph "my-network"
224        API[api container\nport 3000] -- "db:5432" --> DB[db container\nport 5432]
225    end
226    User -- "localhost:3000" --> API
227```
228 
229## Docker Compose
230 
231Hinahayaan ka ng Docker Compose na i-define at patakbuhin ang mga multi-container application gamit ang isang YAML file.
232 
233### docker-compose.yml
234 
235```yaml
236services:
237  api:
238    build: ./api
239    ports:
240      - "3000:3000"
241    environment:
242      - DATABASE_URL=postgres://user:pass@db:5432/mydb
243    depends_on:
244      - db
245 
246  db:
247    image: postgres:16-alpine
248    environment:
249      - POSTGRES_USER=user
250      - POSTGRES_PASSWORD=pass
251      - POSTGRES_DB=mydb
252    volumes:
253      - pgdata:/var/lib/postgresql/data
254    ports:
255      - "5432:5432"
256 
257  redis:
258    image: redis:7-alpine
259    ports:
260      - "6379:6379"
261 
262volumes:
263  pgdata:
264```
265 
266### Mga Command
267 
268```bash
269# Start all services
270docker compose up -d
271 
272# View logs
273docker compose logs -f
274 
275# Stop all services
276docker compose down
277 
278# Rebuild and restart
279docker compose up -d --build
280 
281# Scale a service
282docker compose up -d --scale api=3
283```
284 
285## .dockerignore
286 
287Tulad ng `.gitignore`, pinipigilan ng file na ito ang mga hindi kailangang file na makopya sa image.
288 
289```plaintext
290node_modules
291.git
292.env
293*.md
294.next
295dist
296coverage
297```
298 
299## Mga Pinakamahuhusay na Kasanayan para sa Production
300 
301### 1. Gumamit ng Maliliit na Base Image
302 
303```dockerfile
304# Bad: 1GB+
305FROM node:20
306 
307# Good: ~180MB
308FROM node:20-alpine
309```
310 
311### 2. Huwag Patakbuhin bilang Root
312 
313```dockerfile
314FROM node:20-alpine
315RUN addgroup -S app && adduser -S app -G app
316USER app
317WORKDIR /home/app
318COPY --chown=app:app . .
319```
320 
321### 3. Gumamit ng Specific na Image Tag
322 
323```dockerfile
324# Bad: can change unexpectedly
325FROM node:latest
326 
327# Good: pinned version
328FROM node:20.11-alpine3.19
329```
330 
331### 4. Samantalahin ang Build Cache
332 
333Ayusin ang mga tagubilin ng iyong Dockerfile mula sa pinakamadalang hanggang sa pinakamadalas na nagbabago:
334 
335```dockerfile
336FROM node:20-alpine
337WORKDIR /app
338 
339# These change rarely - cached
340COPY package.json package-lock.json ./
341RUN npm ci --only=production
342 
343# This changes often - not cached
344COPY . .
345```
346 
347### 5. Health Check
348 
349```dockerfile
350HEALTHCHECK --interval=30s --timeout=3s --retries=3 \
351  CMD wget -qO- http://localhost:3000/health || exit 1
352```
353 
354### 6. Gumamit ng Environment Variable
355 
356```dockerfile
357ENV NODE_ENV=production
358ENV PORT=3000
359```
360 
361## Cheat Sheet ng mga Karaniwang Docker Command
362 
363```bash
364# Images
365docker build -t name:tag .        # Build image
366docker images                      # List images
367docker rmi image_name              # Remove image
368docker image prune                 # Remove unused images
369 
370# Containers
371docker run -d -p 3000:3000 image   # Run detached
372docker ps                          # List running
373docker stop container_name         # Stop
374docker rm container_name           # Remove
375docker logs -f container_name      # Follow logs
376docker exec -it container sh       # Shell into container
377 
378# Compose
379docker compose up -d               # Start services
380docker compose down                # Stop services
381docker compose logs -f             # Follow all logs
382docker compose ps                  # List services
383 
384# Cleanup
385docker system prune -a             # Remove everything unused
386```
387 
388## Mula Docker Papuntang Kubernetes
389 
390Pinangangasiwaan ng Docker ang mga indibidwal na container. Kapag kailangan mong i-orchestrate ang daan-daang container sa maraming server, kailangan mo ng Kubernetes. Nagpupunan ang Docker at Kubernetes:
391 
3921. **Docker**: nagbubuo at nagpapatakbo ng mga container
3932. **Kubernetes**: nag-o-orchestrate ng mga container sa malaking sukat (scheduling, scaling, healing)
394 
395Kung interesado ka sa susunod na hakbang, tingnan ang aking artikulo tungkol sa Introduction to Kubernetes.
396 
397## Konklusyon
398 
399Ang Docker ay isang pundamental na kasanayan para sa mga modernong developer. Inaalis nito ang mga hindi pagkakatugma ng kapaligiran, pinapasimple ang deployment, at pundasyon ito ng container orchestration gamit ang Kubernetes. Magsimula sa isang simpleng Dockerfile, lumipat sa Docker Compose para sa mga multi-service app, at i-adopt ang multi-stage build at security best practice habang lumalaki ka.
400 
401Ang pinakamahusay na paraan para matuto ng Docker ay i-containerize ang isang proyekto na ginagawa mo na. Magsimula ngayon.
402