Install Goofys:

wget https://github.com/kahing/goofys/releases/latest/download/goofys
sudo install goofys /usr/local/bin/

Create credentials file ~/.aws/credentials:

[default]
aws_access_key_id=your-key-id
aws_secret_access_key=your-access-key

mount bucket ‘yourbucket’ to /mnt/storage:

goofys --endpoint="https://your.s3.provider.com" yourbucket /mnt/storage

Add this lite to /etc/fstab to mount bucket ‘yourbucket’ to /mnt/storage at boot:

goofys#yourbucket /mnt/storage fuse _netdev,allow_other,--file-mode=0777,--dir-mode=0777,--endpoint=your.s3.provider.com 0 0