Make sure the awslogs launcher script passes the correct environmental variables in order to use ECS Task Roles attached to the Fargate container:
/usr/bin/env -i ECS_CONTAINER_METADATA_URI=${ECS_CONTAINER_METADATA_URI} AWS_CONTAINER_CREDENTIALS_RELATIVE_URI=${AWS_CONTAINER_CREDENTIALS_RELATIVE_URI} HTTPS_PROXY=$HTTPS_PROXY HTTP_PROXY=$HTTP_PROXY NO_PROXY=$NO_PROXY AWS_CONFIG_FILE=/var/awslogs/etc/aws.conf HOME=/root /usr/bin/nice -n 4 /var/awslogs/bin/aws --debug logs push --config-file /var/awslogs/etc/awslogs.conf --additional-configs-dir /var/awslogs/etc/config
These are the important ones:
# env | grep URI ECS_CONTAINER_METADATA_URI=http://169.254.170.2/v3/050390f5-611b-429e-ac2e-e1485fe808ac AWS_CONTAINER_CREDENTIALS_RELATIVE_URI=/v2/credentials/e4656067-72ba-4506-99ed-fee2bdc4aaed