Apa iku Docker Compose lan kenapa mesthi digunakake?

Question

Accepted Answer

**Docker Compose** yaiku piranti kanggo ndefinikaké lan ngjalanke **aplikasi multi-container** nganggo file YAML tunggal. Tinimbang ngjalanke akeh perintah `docker run` kanthi manual, sampeyan njlasake kabeh layanan (app, database, cache) ing `docker-compose.yml` lan mutuhake bebarengan karo siji perintah.

## Masalah sing digatekake Compose

```text
A real app often has MULTIPLE containers: a web app + a database + a cache + ...
  → manually running each with docker run (ports, networks, volumes, env, dependencies)
    is tedious, error-prone, and hard to reproduce/share
→ Compose defines the WHOLE stack in one file → start it all with one command.
```

## File docker-compose.yml

```yaml
services:
  web:
    build: .                    # build from the local Dockerfile
    ports:
      - "3000:3000"             # map ports
    environment:
      - DATABASE_URL=postgres://db:5432/myapp
    depends_on:
      - db                       # start db before web
  db:
    image: postgres:16           # use a prebuilt image
    environment:
      - POSTGRES_PASSWORD=secret
    volumes:
      - dbdata:/var/lib/postgresql/data   # persist the database
volumes:
  dbdata:
```

Siji file ndefinikaké kabeh layanan, image/build-e, port, environment, volume, lan dependensi — lan padha muter ing jaringan (bisa teka siji liyane nganggo jeneng layanan, contone `db`).

## Ngjalanke stack

```bash
docker compose up -d        # build and start ALL services (in the background)
docker compose ps           # list the running services
docker compose logs -f      # view logs from all services
docker compose down         # stop and remove everything
docker compose down -v      # also remove volumes
```

## Mengapa iki penting

Paham Docker Compose iku penting merga aplikasi nyata meh tansah kalebu **akeh container**, lan Compose yaiku piranti standar kanggo manaje-ne, dadi iki pengetahuan praktis sing penting.

Masalahipun nyata: aplikasi umum duwe saweneh layanan (web app, database, cache, mbok menawa message queue), lan ngjalanke saben-saben manual karo perintah `docker run` kapisah — ngatur port, jaringan, volume, variabel environment, lan urutan startup — iku ngrepotake, rawan salah, lan angel diambali utawa dibagi. **Compose** mrigani iki kanthi ndefinikaké **kabeh stack multi-container ing file YAML deklaratif tunggal** lan mutuhake kabeh-e karo siji perintah (`docker compose up`), nggawe aplikasi multi-container gampang dijalanke, diambali, lan dibagi.

Paham struktur `docker-compose.yml` (ndefinikaké layanan kanthi image/build-e, port, environment, volume, lan dependensi, karo layanan sing otomatis jaringan lan bisa teka kanthi jeneng) lan perintah utama (`up`, `down`, `ps`, `logs`) yaiku pengetahuan praktis, saben-dinane kanggo pengembangan lan ngjalanke aplikasi multi-layanan.

Compose utamane berharga kanggo **lingkungan pengembangan lokal** (mutuhake app karo database lan dependensi-e ing siji perintah) lan kanggo ndefinikaké stack aplikasi kanthi teratur.

Merga aplikasi nyata biasane multi-container, lan merga Docker Compose yaiku piranti standar, luwes digunakake kanggo ndefinikaké lan ngjalanke-ne kanthi gampang (ngganti orchestrasi manual sing ngrepotake karo file deklaratif lan perintah tunggal), paham Docker Compose — apa sing digatekake, struktur file compose, lan perintah-e — yaiku pengetahuan penting, kerep digunakake kanggo nggarap aplikasi multi-container, sahabat meh ngeharusake kanggo Docker kanggo aplikasi containerized sing ora gampang lan piranti umum ing workflow pengembangan.