[Loki-distributed] Can't load rules via S3 storage

Hi. I’m trying to use S3 storage mode for Loki-ruler, but my Ruler didn’t load anything from S3. No error log threw. The only warning log I can see is msg="unable to remove user directory" path=/tmp/loki err="unlinkat /tmp/loki: device or resource busy"
How can I set up Ruler to fetch rules from S3, I can’t find any good document for this.