Available endpoints:
POST /container/<ID> - Create a container with specific ID
GET /container/<ID>/state - Get the state of the container
GET /container/<ID>/port/<NUMBER> - Connect to a specific port on a container
GET /container/<ID>/kill - Kill a container
GET /lb - Load balance requests over multiple containers
GET /error - Start a container that errors (demonstrates error handling)
GET /singleton - Get a single specific container instance