You need python-openstackclient
apt -y install python-pip3
pip3 python-openstackclient
You need to get the openrc.sh authentification file from the Public Cloud console
Then you can type (you will be prompted with your password)
source openrc.sh
openstack ec2 credentials create
You will see a table with the specific credentials for the S3 API
ACCESS_KEY
= access in the tableSECRET_KEY
= secret in the tableURL
= https://storage.<region>.cloud.ovh.net (<region> could be rbx gra sbg bhs …)