Longhorn supports MTLS to secure and encrypt the grpc communication between the control plane (longhorn-manager) and the data plane (instance-managers). For Certificate setup we use the Kubernetes secret mechanism in combination with an optional secret mount for the longhorn-manager/instance-manager.

Requirements

In a default installation mtls is disabled to enable mtls support one needs to create a secret in the longhorn-system namespace before deployment. The secret is specified as an optional secret mount for the longhorn-manager/instance-managers so if it does not exist when these components are started, mtls will not be used and a restart of the components will be required to enable tls support.

Self Signed Certificate Setup

You should create a ca.crt with the CA flag set which is then used to sign the tls.crt this will allow you to rotate the tls.crt in the future without service interruptions. You can use openssl or for the ca.crt as well as tls.crt certificate generation.

The tls.crt certificate should use longhorn-backend for the common name and the below list of entries for the Subject Alternative Name.

Setting up Kubernetes Secrets

The longhorn-grpc-tls yaml looks like the below example, If you are having trouble getting your own certificates to work you can base decode the below certificate and compare it against your own generated certificates via openssl x509 -in tls.crt -text -noout.

  1. kind: Secret
  2. metadata:
  4. type: kubernetes.io/tls
  5. data:
  6.   ca.crt: 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
  7.   tls.key: LS0tLS1CRUdJTiBFQyBQUklWQVRFIEtFWS0tLS0tCk1IY0NBUUVFSUwzbjZVZzlhZU1Day9XbkZ2L1pmSTlxMkIyakxnbjFRWGQwcjhIL3k2QkhvQW9HQ0NxR1NNNDkKQXdFSG9VUURRZ0FFTE5BVUllSy92emloZzdrVDl3cThqdThVTnVzbnNhc3ZpaUtVR0J6ZG5WZ3ZTUnczYWM3eApFNFJCOWZnK2NGdVR6ekZoU0dGVUtVSlhpWHl3QVdnSjhRPT0KLS0tLS1FTkQgRUMgUFJJVkFURSBLRVktLS0tLQo=

For more information on creating a secret, see The secret must be created in the longhorn-system namespace for Longhorn to access it.

History

Available since v1.3.0