I am using AWS cloudformation to provision some resources. Part of it is to create an ECS task definition that will mount an EFS access point. A custom resource is defined in Cloudformation which a lambda function in Python will run the ECS Fargate task. However, when I create a stack from the Cloudformation template to provision all the things, the ECS task failed to mount the EFS through the access point with the following error message:
ResourceInitializationError: failed to invoke EFS utils commands to set up EFS volumes: stderr: Failed to resolve "fs-082b4402fbb9c9972.efs.us-east-1.amazonaws.com" - check that your file system ID is correct, and ensure that the VPC has an EFS mount target for this file system ID. See https://docs.aws.amazon.com/console/efs/mount-dns-name for more detail. Attempting to lookup mount target ip address using botocore. Failed to import necessary dependency botocore, please install botocore first. : unsuccessful EFS utils command execution; code: 1
I met similar error before when I created the ECS task in an AZ without a mount target. But it is definitely not the case.
If I run the ECS task manually from the console or run a local python code to run the ECS task, there are no error at all.
Since the cloudformation template are nested templates which create all VPC and other resources together, I am not sure whether the Cloudformation custom resource (Lambda calling ECS task) should have more DependsOn: resources. I have already added the mount targets and acccess point to DependsOn:.
Tried to separate the Cloudformation custom resource into another file so that this part will only be created after all other parts of stack are completed. However, the result is the same.
PS I have added 300 seconds delay to the lambda function which call the ECS task. It works normally afterwards. Then I tried to create the original stack without 300 seconds' delay. The result is also positive. Just wondered what the problem was.