What are Docker health checks and how do you implement them?

Docker health checks monitor container health and enable automatic recovery. Implementation methods: 1) Dockerfile HEALTHCHECK: HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 CMD curl -f http://localhost/ || exit 1, 2) Docker Compose healthcheck with test, interval, timeout, retries, start_period, 3) Runtime health check: docker run -d --health-cmd="curl -f http://localhost || exit 1" --health-interval=30s nginx. Health check states: starting (Initial period), healthy (Check passed), unhealthy (Check failed). Benefits: Automatic container restart, Load balancer integration, Monitoring and alerting, Service discovery.