Meta DevOps Engineer System Design Questions

Meta's applications often rely on various configurations across multiple services. A robust configuration manager ensures that the services get the right configurations seamlessly. Your task is to design a ConfigManager class that handles configuration loading and updates.Problem statement: Define the ConfigManager class that stores configurations for different services and provides methods to retrieve and update these configurations.
- def __init__(self): Initializes the configuration manager.
- def set_config(self, service_id: str, config: Dict[str, Any]) -> None: Sets or updates the configuration for a specific service.
- def get_config(self, service_id: str) -> Dict[str, Any]: Retrieves the configuration for a specific service.Example 1:
Input: config_manager = ConfigManager(); config_manager.set_config('auth_service', {'retry_limit': 3}); config = config_manager.get_config('auth_service')
Output: {'retry_limit': 3}
Explanation: The configuration for 'auth_service' is correctly stored and retrieved.Constraints:
- 1 <= service_id.length <= 100
- The configuration dictionary size can be at most 10^4 key-value pairs.

In Meta's vast microservices ecosystem, persistent health monitoring is crucial to maintain service reliability and uptime. Your task is to design a class that implements a health monitoring system that tracks various services' health statuses.Problem statement: Define a class HealthMonitor that allows registering services and conducting regular health checks.
- def __init__(self): Initializes the health monitor.
- def register_service(self, service_id: str) -> None: Registers a new service to monitor.
- def health_check(self, service_id: str) -> bool: Conducts a health check and returns the service's health; returns True or False.Example 1:
Input: monitor = HealthMonitor(); monitor.register_service('user_service'); status = monitor.health_check('user_service')
Output: True
Explanation: The user_service is registered and passes the health check.Constraints:
- 1 <= service_id.length <= 100
- Health checks should handle at least 10^5 service registrations.