With Amazon STS and kubernetes cluster is configured with
OIDC identity provider, credentials to access Amazon KMS
can be fetched using oidc-token(serviceaccount token).
Each tenant/namespace needs to create a secret with aws region,
role and CMK ARN.
Ceph-CSI will assume the given role with oidc token and access
aws KMS, with given CMK to encrypt/decrypt DEK which will stored
in the image metdata.
Refer: https://docs.aws.amazon.com/STS/latest/APIReference/welcome.htmlResolves: #2879
Signed-off-by: Rakshith R <rar@redhat.com>
