Adding OVHcloud OpenStack-based S3-compatible storage as backup storage in Plesk fails: Unable to check bucket and directory existence

Symptoms

• Adding OVHcloud OpenStack-based S3-compatible storage as a custom S3 storage in Plesk in Tools & Settings > Backup Manager > Remote Storage Settings > Amazon S3 Backup fails:

  Unable to check bucket and directory existence. Make sure you are using correct IAM policy (400 Bad Request (Request-ID: tx2ef843a36acf491fb4b79-005df2411f)).

• The error message stays the same despite what is set in the field Path - the bucket root or a directory inside the bucket.

• Key and secret are created correctly according to the corresponding OVH article.

• Accessing the bucket and working with it using AWS CLI works correctly.

Cause

The region for a custom S3-compatible endpoint is not specified in the file /usr/local/psa/admin/conf/panel.ini.

Resolution

1. Log into Plesk.

2. Install the extension Panel.ini Editor (if it is not installed already).

3. Go to Extensions > My Extensions > Panel.ini Editor > Open > Editor.

4. Add the following lines into the end of the file:

   [ext-s3-backup]
   RegionForCustomEndpoint = GRA

   Note: Replace GRA with the name of the region of your S3-compatible storage provider. Also, in some cases, region should be specified in lowercase, gra (clarify this with the storage provider).

5. Click Save to save the changes.