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.

authentik/blueprint-longhorn-oidc.yaml

@@ -0,0 +1,53 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: authentik-blueprint-longhorn
+data:
+  longhorn-oidc.yaml: |
+    version: 1
+    metadata:
+      name: Longhorn OIDC
+    entries:
+      # Envoy Gateway does the login for Longhorn, which has no users of its
+      # own (see longhorn/httproute.yaml).
+      - model: authentik_providers_oauth2.oauth2provider
+        id: longhorn-provider
+        state: present
+        identifiers:
+          name: Longhorn
+        attrs:
+          name: Longhorn
+          authorization_flow: !Find [authentik_flows.flow, [slug, default-provider-authorization-implicit-consent]]
+          authentication_flow: !Find [authentik_flows.flow, [slug, default-authentication-flow]]
+          invalidation_flow: !Find [authentik_flows.flow, [slug, default-provider-invalidation-flow]]
+          client_type: confidential
+          client_id: longhorn
+          client_secret: !Env [LONGHORN_OIDC_CLIENT_SECRET, ""]
+          redirect_uris:
+            - matching_mode: strict
+              url: https://longhorn.rubenhensen.nl/oauth2/callback
+            # Envoy's test port until the switch from ingress-nginx
+            - matching_mode: strict
+              url: https://longhorn.rubenhensen.nl:10443/oauth2/callback
+          signing_key: !Find [authentik_crypto.certificatekeypair, [name, "authentik Self-signed Certificate"]]
+          property_mappings:
+            - !Find [authentik_providers_oauth2.scopemapping, [managed, goauthentik.io/providers/oauth2/scope-openid]]
+            - !Find [authentik_providers_oauth2.scopemapping, [managed, goauthentik.io/providers/oauth2/scope-email]]
+            - !Find [authentik_providers_oauth2.scopemapping, [managed, goauthentik.io/providers/oauth2/scope-profile]]
+      - model: authentik_core.application
+        id: longhorn-app
+        state: present
+        identifiers:
+          slug: longhorn
+        attrs:
+          name: Longhorn
+          provider: !KeyOf longhorn-provider
+          meta_launch_url: https://longhorn.rubenhensen.nl
+      # Longhorn can delete volumes, so only admins get in.
+      - model: authentik_policies.policybinding
+        state: present
+        identifiers:
+          order: 0
+          target: !KeyOf longhorn-app
+        attrs:
+          group: !Find [authentik_core.group, [name, "authentik Admins"]]

authentik/external-secret.yaml

@@ -135,3 +135,21 @@ spec:
       remoteRef:
         key: kv/actualbudget-oidc
         property: client_secret
+---
+apiVersion: external-secrets.io/v1
+kind: ExternalSecret
+metadata:
+  name: longhorn-oidc-client-secret
+spec:
+  secretStoreRef:
+    name: vault-backend
+    kind: ClusterSecretStore
+  refreshInterval: 15m
+  target:
+    name: longhorn-oidc-client-secret
+    creationPolicy: Owner
+  data:
+    - secretKey: client_secret
+      remoteRef:
+        key: kv/longhorn-oidc
+        property: client_secret