Enable Vault to review kube tokens when using external Vault

We want Vault to perform token reviews with Kubernetes even if we are
using an external Vault.

We need to create the ServiceAccount, Secret and ClusterRoleBinding with
the system:auth-delegator role to enable delegated authentication and
authorization checks [1].

These SA and RBAC objects are created when we deploy the Vault server.
In order to enable the creation of these objects when using an external
Vault, we remove the condition on external mode.
We also improve the visibility of the options we move the serviceAccount
options from the server into the global section. User might want to
provide a sensible name (in global.serviceAccount.name) to the service
account such as: vault-auth.

refs hashicorp#376

[1] https://www.vaultproject.io/docs/auth/kubernetes#configuring-kubernetes

templates/_helpers.tpl

@@ -301,24 +301,24 @@ Sets extra ui service annotations
 Create the name of the service account to use
 */}}
 {{- define "vault.serviceAccount.name" -}}
-{{- if .Values.server.serviceAccount.create -}}
-    {{ default (include "vault.fullname" .) .Values.server.serviceAccount.name }}
+{{- if .Values.global.serviceAccount.create -}}
+    {{ default (include "vault.fullname" .) .Values.global.serviceAccount.name }}
 {{- else -}}
-    {{ default "default" .Values.server.serviceAccount.name }}
+    {{ default "default" .Values.global.serviceAccount.name }}
 {{- end -}}
 {{- end -}}
 
 {{/*
 Sets extra service account annotations
 */}}
 {{- define "vault.serviceAccount.annotations" -}}
-  {{- if and (ne .mode "dev") .Values.server.serviceAccount.annotations }}
+  {{- if and (ne .mode "dev") .Values.global.serviceAccount.annotations }}
   annotations:
-    {{- $tp := typeOf .Values.server.serviceAccount.annotations }}
+    {{- $tp := typeOf .Values.global.serviceAccount.annotations }}
     {{- if eq $tp "string" }}
-      {{- tpl .Values.server.serviceAccount.annotations . | nindent 4 }}
+      {{- tpl .Values.global.serviceAccount.annotations . | nindent 4 }}
     {{- else }}
-      {{- toYaml .Values.server.serviceAccount.annotations | nindent 4 }}
+      {{- toYaml .Values.global.serviceAccount.annotations | nindent 4 }}
     {{- end }}
   {{- end }}
 {{- end -}}

templates/server-clusterrolebinding.yaml

@@ -1,5 +1,4 @@
 {{ template "vault.mode" . }}
-{{- if ne .mode "external" }}
 {{- if and (ne .mode "") (and (eq (.Values.global.enabled | toString) "true") (eq (.Values.server.authDelegator.enabled | toString) "true")) }}
 apiVersion: rbac.authorization.k8s.io/v1beta1
 kind: ClusterRoleBinding
@@ -19,4 +18,3 @@ subjects:
   name: {{ template "vault.serviceAccount.name" . }}
   namespace: {{ .Release.Namespace }}
 {{ end }}
-{{ end }}

templates/server-serviceaccount.yaml

@@ -1,7 +1,6 @@
 {{ template "vault.mode" . }}
-{{- if ne .mode "external" }}
 {{- if and (ne .mode "") (eq (.Values.global.enabled | toString) "true") }}
-{{- if (eq (.Values.server.serviceAccount.create | toString) "true" ) }}
+{{- if (eq (.Values.global.serviceAccount.create | toString) "true" ) }}
 apiVersion: v1
 kind: ServiceAccount
 metadata:
@@ -15,4 +14,3 @@ metadata:
   {{ template "vault.serviceAccount.annotations" . }}
 {{ end }}
 {{ end }}
-{{ end }}

test/unit/server-serviceaccount.bats

@@ -8,15 +8,15 @@ load _helpers
   local actual=$( (helm template \
       --show-only templates/server-serviceaccount.yaml  \
       --set 'server.dev.enabled=true' \
-      --set 'server.serviceAccount.create=false' \
+      --set 'global.serviceAccount.create=false' \
       . || echo "---") | tee /dev/stderr |
       yq 'length > 0' | tee /dev/stderr)
   [ "${actual}" = "false" ]
 
   local actual=$(helm template \
       --show-only templates/server-serviceaccount.yaml  \
       --set 'server.dev.enabled=true' \
-      --set 'server.serviceAccount.name=user-defined-ksa' \
+      --set 'global.serviceAccount.name=user-defined-ksa' \
       . | tee /dev/stderr |
       yq -r '.metadata.name' | tee /dev/stderr)
   [ "${actual}" = "user-defined-ksa" ]
@@ -35,23 +35,23 @@ load _helpers
   local actual=$(helm template \
       --show-only templates/server-serviceaccount.yaml  \
       --set 'server.dev.enabled=true' \
-      --set 'server.serviceAccount.annotations=foo: bar' \
+      --set 'global.serviceAccount.annotations=foo: bar' \
       . | tee /dev/stderr |
       yq -r '.metadata.annotations["foo"]' | tee /dev/stderr)
   [ "${actual}" = "null" ]
 
   local actual=$(helm template \
       --show-only templates/server-serviceaccount.yaml  \
       --set 'server.ha.enabled=true' \
-      --set 'server.serviceAccount.annotations=foo: bar' \
+      --set 'global.serviceAccount.annotations=foo: bar' \
       . | tee /dev/stderr |
       yq -r '.metadata.annotations["foo"]' | tee /dev/stderr)
   [ "${actual}" = "bar" ]
 
   local actual=$(helm template \
       --show-only templates/server-serviceaccount.yaml  \
       --set 'server.ha.enabled=true' \
-      --set 'server.serviceAccount.annotations.foo=bar' \
+      --set 'global.serviceAccount.annotations.foo=bar' \
       . | tee /dev/stderr |
       yq -r '.metadata.annotations["foo"]' | tee /dev/stderr)
   [ "${actual}" = "bar" ]

test/unit/server-statefulset.bats

@@ -1407,16 +1407,16 @@ load _helpers
 
  local actual=$(helm template \
       --show-only templates/server-statefulset.yaml  \
-      --set 'server.serviceAccount.create=false' \
-      --set 'server.serviceAccount.name=user-defined-ksa' \
+      --set 'global.serviceAccount.create=false' \
+      --set 'global.serviceAccount.name=user-defined-ksa' \
       . | tee /dev/stderr |
       yq -r '.spec.template.spec.serviceAccountName' | tee /dev/stderr)
   [ "${actual}" = "user-defined-ksa" ]
 
  local actual=$(helm template \
       --show-only templates/server-statefulset.yaml  \
-      --set 'server.serviceAccount.create=true' \
-      --set 'server.serviceAccount.name=user-defined-ksa' \
+      --set 'global.serviceAccount.create=true' \
+      --set 'global.serviceAccount.name=user-defined-ksa' \
       . | tee /dev/stderr |
       yq -r '.spec.template.spec.serviceAccountName' | tee /dev/stderr)
   [ "${actual}" = "user-defined-ksa" ]
@@ -1427,14 +1427,14 @@ load _helpers
 
  local actual=$(helm template \
       --show-only templates/server-statefulset.yaml  \
-      --set 'server.serviceAccount.create=false' \
+      --set 'global.serviceAccount.create=false' \
       . | tee /dev/stderr |
       yq -r '.spec.template.spec.serviceAccountName' | tee /dev/stderr)
   [ "${actual}" = "default" ]
 
  local actual=$(helm template \
       --show-only templates/server-statefulset.yaml  \
-      --set 'server.serviceAccount.create=true' \
+      --set 'global.serviceAccount.create=true' \
       . | tee /dev/stderr |
       yq -r '.spec.template.spec.serviceAccountName' | tee /dev/stderr)
   [ "${actual}" = "RELEASE-NAME-vault" ]

values.yaml

@@ -22,6 +22,19 @@ global:
       apparmor.security.beta.kubernetes.io/allowedProfileNames: runtime/default
       seccomp.security.alpha.kubernetes.io/defaultProfileName:  runtime/default
       apparmor.security.beta.kubernetes.io/defaultProfileName:  runtime/default
+  # Definition of the serviceAccount used to run Vault.
+  # These options are also used when using an external Vault server to validate
+  # Kubernetes tokens.
+  serviceAccount:
+    # Specifies whether a service account should be created
+    create: true
+    # The name of the service account to use.
+    # If not set and create is true, a name is generated using the fullname template
+    name: ""
+    # Extra annotations for the serviceAccount definition. This can either be
+    # YAML or a YAML-formatted multi-line templated string map of the
+    # annotations to apply to the serviceAccount.
+    annotations: {}
 
 injector:
   # True if you want to enable vault agent injection.
@@ -526,17 +539,6 @@ server:
     # replicas. If you'd like a custom value, you can specify an override here.
       maxUnavailable: null
 
-  # Definition of the serviceAccount used to run Vault.
-  serviceAccount:
-    # Specifies whether a service account should be created
-    create: true
-    # The name of the service account to use.
-    # If not set and create is true, a name is generated using the fullname template
-    name: ""
-    # Extra annotations for the serviceAccount definition. This can either be
-    # YAML or a YAML-formatted multi-line templated string map of the
-    # annotations to apply to the serviceAccount.
-    annotations: {}
 
   # Settings for the statefulSet used to run Vault.
   statefulSet: