Add annotation on config change

When updating the Vault config (and corresponding)
configmap, we now generate a checksum of the config
and set it as an annotation on both the configmap
and the Vault StatefulSet pod template.

This allows the deployer to know what pods need to
be restarted to pick up the a changed config.

We still recommend using the standard upgrade
[method for Vault on Kubernetes](https://developer.hashicorp.com/vault/tutorials/kubernetes/kubernetes-raft-deployment-guide#upgrading-vault-on-kubernetes),
i.e., using the `OnDelete` strategy
for the Vault StatefulSet, so updating the config
and doing a `helm upgrade` should not trigger the
pods to restart, and then deleting pods one
at a time, starting with the standby pods.

With `kubectl` and `jq`, you can check check which
pods need to be updated by first getting the value
of the current configmap checksum:

```shell
kubectl get pods -o json | jq -r ".items[] | select(.metadata.annotations.\"config/checksum\" != $(kubectl get configmap vault-config -o json | jq '.metadata.annotations."config/checksum"') ) | .metadata.name"
```

Fixes #748.

templates/_helpers.tpl

@@ -457,9 +457,10 @@ Sets the injector deployment update strategy
 {{/*
 Sets extra pod annotations
 */}}
-{{- define "vault.annotations" -}}
-  {{- if .Values.server.annotations }}
+{{- define "vault.annotations" }}
       annotations:
+        config/checksum: {{ include "vault.config" . | sha256sum }}
+  {{- if .Values.server.annotations }}
         {{- $tp := typeOf .Values.server.annotations }}
         {{- if eq $tp "string" }}
           {{- tpl .Values.server.annotations . | nindent 8 }}
@@ -1075,3 +1076,28 @@ Supported inputs are Values.ui
 {{- end -}}
 {{- end }}
 {{- end -}}
+
+{{/*
+config file from values
+*/}}
+{{- define "vault.config" -}}
+  {{- if or (eq .mode "ha") (eq .mode "standalone") }}
+  {{- $type := typeOf (index .Values.server .mode).config }}
+  {{- if eq $type "string" }}
+    disable_mlock = true
+  {{- if eq .mode "standalone" }}
+    {{ tpl .Values.server.standalone.config . | nindent 4 | trim }}
+  {{- else if and (eq .mode "ha") (eq (.Values.server.ha.raft.enabled | toString) "false") }}
+    {{ tpl .Values.server.ha.config . | nindent 4 | trim }}
+  {{- else if and (eq .mode "ha") (eq (.Values.server.ha.raft.enabled | toString) "true") }}
+    {{ tpl .Values.server.ha.raft.config . | nindent 4 | trim }}
+  {{ end }}
+  {{- else }}
+  {{- if and (eq .mode "ha") (eq (.Values.server.ha.raft.enabled | toString) "true") }}
+{{ merge (dict "disable_mlock" true) (index .Values.server .mode).raft.config | toPrettyJson | indent 4 }}
+  {{- else }}
+{{ merge (dict "disable_mlock" true) (index .Values.server .mode).config | toPrettyJson | indent 4 }}
+  {{- end }}
+  {{- end }}
+  {{- end }}
+{{- end -}}

templates/server-config-configmap.yaml

@@ -18,27 +18,11 @@ metadata:
     app.kubernetes.io/name: {{ include "vault.name" . }}
     app.kubernetes.io/instance: {{ .Release.Name }}
     app.kubernetes.io/managed-by: {{ .Release.Service }}
+  annotations:
+    config/checksum: {{ include "vault.config" . | sha256sum }}
 data:
   extraconfig-from-values.hcl: |-
-  {{- if or (eq .mode "ha") (eq .mode "standalone") }}
-  {{- $type := typeOf (index .Values.server .mode).config }}
-  {{- if eq $type "string" }}
-    disable_mlock = true
-  {{- if eq .mode "standalone" }}
-    {{ tpl .Values.server.standalone.config . | nindent 4 | trim }}
-  {{- else if and (eq .mode "ha") (eq (.Values.server.ha.raft.enabled | toString) "false") }}
-    {{ tpl .Values.server.ha.config . | nindent 4 | trim }}
-  {{- else if and (eq .mode "ha") (eq (.Values.server.ha.raft.enabled | toString) "true") }}
-    {{ tpl .Values.server.ha.raft.config . | nindent 4 | trim }}
-  {{ end }}
-  {{- else }}
-  {{- if and (eq .mode "ha") (eq (.Values.server.ha.raft.enabled | toString) "true") }}
-{{ merge (dict "disable_mlock" true) (index .Values.server .mode).raft.config | toPrettyJson | indent 4 }}
-  {{- else }}
-{{ merge (dict "disable_mlock" true) (index .Values.server .mode).config | toPrettyJson | indent 4 }}
-  {{- end }}
-  {{- end }}
-  {{- end }}
+    {{ template "vault.config" . }}
 {{- end }}
 {{- end }}
 {{- end }}