Startup of ECS Fargate task fails with ResourceInitializationError mount.nfs4 Connection timed out When starting up an Amazon ECS task with launch type FARGATE it fails with the following reason:

ResourceInitializationError: failed to invoke EFS utils commands to set up EFS volumes: command failed with 32: failed to execute command to invoke EFS utils: mount.nfs4:

Connection timed out


The fargate task is a docker image that needs to mount EFS as persistent storage. 

Why is the connection timing out?
Underlying reason:

The ECS service's network access security group did not have permission to access EFS.

Solution:

Add an inbound rule for type NFS in the security group as described in this tutorial: https://docs.aws.amazon.com/AmazonECS/latest/developerguide/tutorial-efs-volumes.html#efs-security-group