How to fix Container is starting (health: starting) in Docker

# View container health status
docker ps

# Get detailed health configuration and status
docker inspect <container_name> --format='{{json .State.Health}}' | jq

# See the complete health check configuration
docker inspect <container_name> --format='{{json .Config.Healthcheck}}' | jq

{
  "Status": "starting",
  "FailingStreak": 0,
  "Log": []
}

{
  "Test": ["CMD-SHELL", "curl -f http://localhost:8080/health"],
  "Interval": 30000000000,
  "Timeout": 10000000000,
  "StartPeriod": 0,
  "Retries": 3
}

# For a typical web application (30-60 second startup)
HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1

# For slow-starting apps like Java/databases (2-5 minute startup)
HEALTHCHECK --interval=30s --timeout=10s --start-period=300s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1

services:
  web:
    image: myapp
    healthcheck:
      test: ["CMD-SHELL", "curl -f http://localhost:8080/health || exit 1"]
      interval: 30s
      timeout: 10s
      start_period: 60s
      retries: 3

  database:
    image: postgres:15
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 10s
      timeout: 5s
      start_period: 120s  # Databases need more time
      retries: 5

HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --start-interval=5s --retries=3 \
  CMD curl -f http://localhost:8080/health || exit 1

services:
  web:
    image: myapp
    healthcheck:
      test: ["CMD-SHELL", "curl -f http://localhost:8080/health || exit 1"]
      interval: 30s
      timeout: 10s
      start_period: 60s
      start_interval: 5s  # Check every 5s during start_period
      retries: 3

# Execute the health check command directly
docker exec <container_name> curl -f http://localhost:8080/health
echo "Exit code: $?"

# Or get a shell and test interactively
docker exec -it <container_name> sh

# Inside the container:
curl -f http://localhost:8080/health
echo $?

# Alpine - use wget instead of curl
HEALTHCHECK CMD wget --spider -q http://localhost:8080/health || exit 1

# Or install curl
RUN apk add --no-cache curl

docker exec <container_name> netstat -tlnp

HEALTHCHECK CMD curl -f http://127.0.0.1:8080/health || exit 1

# Watch container status continuously
watch -n 2 'docker ps --format "table {{.Names}}	{{.Status}}"'

# Monitor Docker events for health status changes
docker events --filter container=<container_name> --filter event=health_status

# Check health check logs as they accumulate
watch -n 5 'docker inspect <container_name> --format="{{json .State.Health}}" | jq'

{
  "Status": "starting",
  "FailingStreak": 0,
  "Log": [
    {
      "Start": "2024-01-15T10:00:00.000Z",
      "End": "2024-01-15T10:00:01.000Z",
      "ExitCode": 1,
      "Output": "curl: (7) Failed to connect"
    },
    {
      "Start": "2024-01-15T10:00:30.000Z",
      "End": "2024-01-15T10:00:30.500Z",
      "ExitCode": 0,
      "Output": "OK"
    }
  ]
}

services:
  web:
    image: myapp
    depends_on:
      db:
        condition: service_healthy
      redis:
        condition: service_healthy

  db:
    image: postgres:15
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 10s
      timeout: 5s
      start_period: 60s
      retries: 5

  redis:
    image: redis:7
    healthcheck:
      test: ["CMD", "redis-cli", "ping"]
      interval: 10s
      timeout: 5s
      start_period: 30s
      retries: 3

healthcheck:
  test: ["CMD-SHELL", "pg_isready -U postgres"]
  interval: 30s
  timeout: 5s
  start_period: 30s
  start_interval: 2s  # Quick checks during startup
  retries: 5

// Node.js - lazy database connection
let dbConnection;
app.get('/health', (req, res) => {
  res.status(200).send('OK');  // Basic health check
});

async function getDb() {
  if (!dbConnection) {
    dbConnection = await connectToDatabase();
  }
  return dbConnection;
}

# Basic health check that passes early
healthcheck:
  test: ["CMD-SHELL", "curl -f http://localhost:8080/health/live || exit 1"]
  interval: 10s
  start_period: 10s

# Wait script for CI pipelines
until docker inspect --format='{{.State.Health.Status}}' mycontainer | grep -q "healthy"; do
  echo "Waiting for container to be healthy..."
  sleep 2
done

FROM node:20 AS builder
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

FROM node:20-slim
WORKDIR /app
COPY --from=builder /app/dist ./dist
COPY --from=builder /app/node_modules ./node_modules
CMD ["node", "dist/index.js"]