s3: use aws web identity role provider

backend/s3/s3.go

@@ -37,6 +37,7 @@ import (
 	"github.com/aws/aws-sdk-go/aws/corehandlers"
 	"github.com/aws/aws-sdk-go/aws/credentials"
 	"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
+	"github.com/aws/aws-sdk-go/aws/credentials/stscreds"
 	"github.com/aws/aws-sdk-go/aws/defaults"
 	"github.com/aws/aws-sdk-go/aws/ec2metadata"
 	"github.com/aws/aws-sdk-go/aws/request"
@@ -1009,6 +1010,11 @@ func s3Connection(opt *Options) (*s3.S3, *session.Session, error) {
 			}),
 			ExpiryWindow: 3 * time.Minute,
 		},
+
+		// Pick up IAM role if we are in EKS
+		&stscreds.WebIdentityRoleProvider{
+			ExpiryWindow: 3 * time.Minute,
+		},
 	}
 	cred := credentials.NewChainCredentials(providers)
 

docs/content/s3.md

@@ -358,6 +358,7 @@ The different authentication methods are tried in this order:
          - `AWS_PROFILE` to control which profile to use.
    - Or, run `rclone` in an ECS task with an IAM role (AWS only).
    - Or, run `rclone` on an EC2 instance with an IAM role (AWS only).
+   - Or, run `rclone` in an EKS pod with an IAM role that is associated with a service account (AWS only).
 
 If none of these option actually end up providing `rclone` with AWS
 credentials then S3 interaction will be non-authenticated (see below).