How do I specify that I want to use Instance profile credentials when using the AWS CLI from within my EC2 instance? the docs say:
Instance profile credentials – these credentials can be used on EC2
instances with an assigned instance role, and are delivered through
the Amazon EC2 metadata service.
Is this automatic or do I need to call the metadata service and save the returned credentials to the ~/.aws/credentials file...then make the call?
You are talking about IAM Roles. These are attached to the EC2 instance and the keys are rolled/rotated every four hours.
You do not need to pull those from the instance metadata and supply it to the aws-cli or a SDK, they will pull it automatically.
If you run aws-cli with the --debug flag, you should see the credentials being picked up:
$ aws --debug s3 ls
...
2015-03-10 18:15:04,459 - MainThread - botocore.credentials - DEBUG - Looking for credentials via: iam-role
2015-03-10 18:15:04,465 - MainThread - botocore.vendored.requests.packages.urllib3.connectionpool - INFO - Starting new HTTP connection (1): 169.254.169.254
2015-03-10 18:15:04,466 - MainThread - botocore.vendored.requests.packages.urllib3.connectionpool - DEBUG - "GET /latest/meta-data/iam/security-credentials/ HTTP/1.1" 200 37
2015-03-10 18:15:04,468 - MainThread - botocore.vendored.requests.packages.urllib3.connectionpool - INFO - Starting new HTTP connection (1): 169.254.169.254
2015-03-10 18:15:04,469 - MainThread - botocore.vendored.requests.packages.urllib3.connectionpool - DEBUG - "GET /latest/meta-data/iam/security-credentials/myrole-snipped HTTP/1.1" 200 898
2015-03-10 18:15:04,469 - MainThread - botocore.credentials - INFO - Found credentials from IAM Role: myrole-snipped
latest/meta-data/iam/security-credentials/ actually on the server? Or is this intercepted outside of the instance.
--debug flag. That was a lifesaver