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HealthCheck | Docker

  • HealthCheck | Docker

🧩 Documentação oficial​

👉 Docker Docs – HEALTHCHECK

⚙️ Sintaxe básica (Dockerfile ou docker-compose.yml)​

healthcheck:
  test: ["CMD", "comando", "argumentos"]
  interval: 30s      # tempo entre verificações
  timeout: 10s       # tempo máximo do comando
  retries: 3         # quantas falhas antes de marcar 'unhealthy'
  start_period: 5s   # tempo antes de iniciar as verificações (opcional)

🧠 Exemplos práticos​

🟥 Redis​

services:
  redis:
    image: redis:7
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 30s
      timeout: 5s
      retries: 3

Espera resposta “PONG” para marcar como saudável.

🟦 PostgreSQL​

services:
  postgres:
    image: postgres:16
    environment:
      POSTGRES_PASSWORD: example
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 30s
      timeout: 10s
      retries: 5

Usa o utilitário interno pg_isready para testar conexão.

🟩 API / Web service (genérico)​

services:
  web:
    build: .
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8080/health"]
      interval: 30s
      timeout: 10s
      retries: 3

🟧 MySQL​

services:
  mysql:
    image: mysql:8
    environment:
      MYSQL_ROOT_PASSWORD: example
    healthcheck:
      test: ["CMD-SHELL", "mysqladmin ping -h localhost -p$$MYSQL_ROOT_PASSWORD | grep 'mysqld is alive'"]
      interval: 30s
      timeout: 10s
      retries: 5

🟨 Nginx​

services:
  nginx:
    image: nginx:latest
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost" ]
      interval: 30s
      timeout: 5s
      retries: 3