feat(mok): Add ability to set define hostname for postfix

This patch allows to set the `HOSTNAME` variable, which should
explicitly set the hostname for the postfix pod and configure it to use
the proper external DNS name.

charts/mok/Chart.yaml

@@ -3,7 +3,7 @@ name: mok
 description: |
   Mail on Kubernetes (MoK) is a project to deploy a functional mailserver that runs without a database server on Kubernetes, taking advantage of configmaps and secret.
 type: application
-version: 0.5.2
+version: 0.6.0
 sources:
   - https://de.postfix.org/ftpmirror/index.html
   - https://github.com/dovecot/core

charts/mok/README.md

 # mok
 
-![Version: 0.5.2](https://img.shields.io/badge/Version-0.5.2-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square)
+![Version: 0.6.0](https://img.shields.io/badge/Version-0.6.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square)
 
 Mail on Kubernetes (MoK) is a project to deploy a functional mailserver that runs without a database server on Kubernetes, taking advantage of configmaps and secret.
 
@@ -53,6 +53,7 @@ Mail on Kubernetes (MoK) is a project to deploy a functional mailserver that run
 | nameOverride | string | `""` |  |
 | networkPolicy.create | bool | `true` | Create NetworkPolicies to access the mailserver from outside |
 | postfix.affinity | object | `{}` |  |
+| postfix.hostname | string | `nil` | explicitly set postfix hostname |
 | postfix.image.pullPolicy | string | `"IfNotPresent"` |  |
 | postfix.image.repository | string | `"quay.io/shivering-isles/postfix"` | postfix container image |
 | postfix.image.tag | string | `"0.2.3"` | Overrides the image tag whose default is "latest" |

charts/mok/templates/postfix.yaml

@@ -75,6 +75,10 @@ spec:
           env:
             - name: DOVECOT_SERVICE_NAME
               value: {{ include "mok.fullname" . }}-dovecot-internal.{{ .Release.Namespace }}.svc.cluster.local
+            {{- if .Values.postfix.hostname }}
+            - name: HOSTNAME
+              value: {{ .Values.postfix.hostname }}
+            {{- end }}
           image: {{ .Values.postfix.image.repository }}:{{.Values.postfix.image.tag | default "latest" }}
           imagePullPolicy: {{ .Values.postfix.image.pullPolicy }}
           lifecycle:

charts/mok/values.yaml

@@ -36,6 +36,8 @@ relay:
 
 
 postfix:
+  # -- explicitly set postfix hostname
+  hostname: null
   # -- Number of postfix pods.
   replicaCount: 1