Mount an S3 bucket using IAM roles

After much searching around I discovered that newer versions of s3fs support IAM roles (I’m using 1.77). Unfortunately, this functionality is barely documented.

I ended up using the following line to mount my directory:

s3fs bucketname /mnt/bucket -o use_cache=/tmp,allow_other,iam_role=`curl http://169.254.169.254/latest/meta-data/iam/security-credentials/`

NB: s3fs does not need s3://

If the role you’re trying to use does not have access you’ll get something like this:

$ ls /mnt
total 20
drwxr-xr-x 5 root root 4096 Jun 16 23:39 .
drwxr-xr-x 7 root root 4096 Jun 16 23:39 ..
d????????? ? ?   ?       ?            ? bucket

The other error message I’ve seen is:

touch: cannot touch ‘/mnt/bucket/test.txt’: Transport endpoint is not connected

This happened when I specified the role incorrectly (it does not need to be the full arn).