longhorn: log in through authentik on the Gateway

Longhorn has no users of its own; nginx guarded it with basic auth using apr1 hashes, which Envoy Gateway does not support. An Envoy Gateway SecurityPolicy now sends visitors through an authentik OIDC application that only admins may use. The client secret lives in Vault at kv/longhorn-oidc and reaches both authentik and Envoy through External Secrets.

apps/templates/authentik-helm.yaml

@@ -86,6 +86,11 @@ spec:
                   secretKeyRef:
                     name: actualbudget-oidc-client-secret
                     key: client_secret
+              - name: LONGHORN_OIDC_CLIENT_SECRET
+                valueFrom:
+                  secretKeyRef:
+                    name: longhorn-oidc-client-secret
+                    key: client_secret
               # Point OpenSSL and requests (which uses certifi otherwise) at
               # patched-ca-bundle, mounted below until the image drops the
               # compromised eMudhra intermediates.
@@ -119,6 +124,9 @@ spec:
               - name: blueprint-session
                 configMap:
                   name: authentik-blueprint-session
+              - name: blueprint-longhorn
+                configMap:
+                  name: authentik-blueprint-longhorn
             volumeMounts:
               - name: blueprint-vault
                 mountPath: /blueprints/custom/vault-oidc.yaml
@@ -141,6 +149,9 @@ spec:
               - name: blueprint-session
                 mountPath: /blueprints/custom/session-duration.yaml
                 subPath: session-duration.yaml
+              - name: blueprint-longhorn
+                mountPath: /blueprints/custom/longhorn-oidc.yaml
+                subPath: longhorn-oidc.yaml
               - name: patched-ca-bundle
                 mountPath: /etc/ssl/certs
                 readOnly: true
@@ -181,6 +192,9 @@ spec:
               - name: blueprint-session
                 configMap:
                   name: authentik-blueprint-session
+              - name: blueprint-longhorn
+                configMap:
+                  name: authentik-blueprint-longhorn
             volumeMounts:
               - name: blueprint-vault
                 mountPath: /blueprints/custom/vault-oidc.yaml
@@ -203,6 +217,9 @@ spec:
               - name: blueprint-session
                 mountPath: /blueprints/custom/session-duration.yaml
                 subPath: session-duration.yaml
+              - name: blueprint-longhorn
+                mountPath: /blueprints/custom/longhorn-oidc.yaml
+                subPath: longhorn-oidc.yaml
               - name: patched-ca-bundle
                 mountPath: /etc/ssl/certs
                 readOnly: true