containerPort

The port value to be used for your service discovery service. It's already specified in the task definition. If the task definition your service task specifies uses the bridge or host network mode, you must specify a containerName and containerPort combination from the task definition. If the task definition your service task specifies uses the awsvpc network mode and a type SRV DNS record is used, you must specify either a containerName and containerPort combination or a port value. However, you can't specify both.