既存のアップロードファイルを Digital Ocean Spaces へ移行するサポートが必要です（S3 の設定は正常に完了しており、新しいアップロードは正常に保存されています）。
以下のコマンドで rake uploads:migrate_to_s3 を実行しました：
DISCOURSE_S3_ACCESS_KEY_ID="id" \
DISCOURSE_S3_SECRET_ACCESS_KEY="secret" \
DISCOURSE_S3_REGION="sfo2" \
DISCOURSE_S3_BUCKET="mybucket/uploads" \
DISCOURSE_S3_ENDPOINT="https://mybucket.sfo2.digitaloceanspaces.com" \
DRY_RUN=1 rake uploads:migrate_to_s3 --trace
しかし、rake タスクは以下のように中止されました：
Seahorse::Client::NetworkingError: SSL_connect returned=1 errno=0 state=error: certificate verify failed (unspecified certificate verification error)
これは、DO Spaces 用のルート証明書が不足している可能性を示しており、以下の issue で報告されています：
結論から言うと、Ruby SDK はもはや SSL 証明書をバンドルしていません。代わりに、Ruby 内の OpenSSL が正しく設定されていることに依存しています。上記の関連 issue には、その設定が正しくない場合の簡単な回避策がいくつか記載されています。
その回避策の一つには、以下のように設定することが挙げられています：
Aws.config[:ssl_ca_bundle] = '/path/to/ca-bundle.crt'
ファイルを /shared/ca-bundle.crt にダウンロードし、Rails コンソールで設定しましたが、これを永続化することができないようです（rake タスクは再度失敗し、Rails コンソールで設定を確認すると、nil に戻ってしまっています）。
完全なトレースログ：
** Invoke uploads:migrate_to_s3 (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute uploads:migrate_to_s3
Checking if default already migrated...
13252 of 13261 uploads are not migrated to S3. S3 migration failed for db 'default'.
10052 posts are not remapped to new S3 upload URL. S3 migration failed for db 'default'.
** Invoke posts:missing_uploads (first_time)
** Invoke environment
** Execute posts:missing_uploads
Looking for missing uploads on: default
0 post uploads are missing.
Looking for missing uploads on: default
0 post uploads are missing.
No posts require rebaking
****************************** DRY RUN ******************************
Migrating uploads to S3 for 'default'...
Uploading files to S3...
- Listing local files
.............. => 14025 files
- Listing S3 files
rake aborted!
Seahorse::Client::NetworkingError: SSL_connect returned=1 errno=0 state=error: certificate verify failed (unspecified certificate verification error)
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Tasks: TOP => uploads:migrate_to_s3
。バケット名のプレフィックスを含まない場所のみを含める必要があります（admin — サイト設定 — S3 エンドポイントで定義されているものと同じ）：