ANDUの検証が失敗し、「One or more encryption keys are unavailable」というエラーが表示される

環境

• ONTAP 9
• 自動無停止アップグレード（ ANDU ）
• オンボードキーマネージャ（ OTM ）

問題

• ONTAP をアップグレードしようとすると、クラスタイメージの検証が次のエラーで失敗します。 

Error: One or more encryption keys are unavailable.

cluster::> cluster image update -version <version>
Starting validation for this update...
It can take several minutes to complete validation...
...
Pre-update Check    Status    Error-Action
--------------------- ---------- --------------------------------------------
Encryption Keys     Error    Error: One or more encryption keys are
status               unavailable.
                 Action: Restore missing encryption keys
                 before starting ANDU. To check missing keys,
                 run "security key-manager key query
                 -restored false". To restore onboard key
                 manager keys, run "security key-manager
                 onboard sync" command. To restore external
                 key manager keys, run "security key-manager
                 external restore" command. To restore Azure
                 Key Vault keys, run the "security
                 key-manager external azure restore"
                 command. To restore Google Cloud Key
                 Management Service keys, run the "security
                 key-manager external gcp restore" command.

• ANDU検証が実行後も失敗し続ける： security key-manager onboard sync