如何通过Helm在EKS蓝绿部署中更新Deployment的route标签

核心需求分析 #

你需要在切换productionSlot时，同步更新蓝/绿两个Deployment及其Pod的route标签，但不想通过修改enabled字段触发Pod重建。

方案1：仅更新Deployment标签（无需Pod标签变更） #

如果route标签仅用于标识Deployment而非Pod，可通过调整模板避免Pod重建：

步骤1：修改Deployment模板 #

将route标签仅保留在Deployment的元数据标签中，移除Pod模板中的route标签：

{{- define "blue-green-deploy.deployment" -}}
{{- $currSlot := (pluck .currSlot .Values | first) }}
{{- $isProduction := eq .currSlot .Values.productionSlot }}
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "blue-green-deploy.fullname" . }}-{{ .currSlot }}
  labels:
    release: {{ .Release.Name }}
    chart: "{{ .Chart.Name }}-{{ .Chart.Version }}"
    app: {{ template "blue-green-deploy.name" . }}
    version: {{ $currSlot.appVersion | quote }}
    slot: {{ .currSlot }}
    route: {{ if $isProduction }}primary{{ else }}alt{{ end }}
spec:
  replicas: {{ $currSlot.replicas | default 1 }}
  selector:
    matchLabels:
      app: {{ template "blue-green-deploy.name" . }}
      slot: {{ .currSlot }}
  template:
    metadata:
      labels:
        release: {{ .Release.Name }}
        app: {{ template "blue-green-deploy.name" . }}
        version: {{ $currSlot.appVersion | quote }}
        slot: {{ .currSlot }}
        # 移除此处的route标签，避免触发Pod重建
    spec:
      containers:
      - name: {{ .Chart.Name }}
        image: "{{ .Values.image.name }}:{{ index .Values.image (printf "%s_tag" .currSlot) }}"
        ...
{{- end }}

步骤2：保持部署槽位始终启用 #

首次部署后，确保values.yaml中blue.enabled和green.enabled均为true，避免Helm删除任一Deployment。

步骤3：执行路由切换 #

继续使用原命令切换路由：

helm upgrade test-app . --namespace test --install --set productionSlot=green --reuse-values --wait

此时Helm仅更新两个Deployment的元数据标签，不会修改Pod模板，因此不会触发Pod重建。

方案2：同步更新Pod标签（不重建Pod） #

若必须更新Pod上的route标签，可通过Helm Post-Upgrade Hook执行kubectl patch修改Pod标签：

步骤1：创建标签更新Job（Hook） #

在templates目录下创建patch-pod-labels.yaml：

apiVersion: batch/v1
kind: Job
metadata:
  name: {{ include "blue-green-deploy.fullname" . }}-patch-pod-labels
  annotations:
    "helm.sh/hook": post-upgrade
    "helm.sh/hook-weight": "5"
    "helm.sh/hook-delete-policy": hook-succeeded
spec:
  template:
    spec:
      restartPolicy: OnFailure
      serviceAccountName: {{ include "blue-green-deploy.fullname" . }}-patch-sa
      containers:
      - name: kubectl
        image: bitnami/kubectl:latest
        command:
        - /bin/sh
        - -c
        - |
          # 更新主槽位Pod的route标签为primary
          kubectl patch pods -l app={{ template "blue-green-deploy.name" . }},slot={{ .Values.productionSlot }} -p '{"metadata":{"labels":{"route":"primary"}}}'
          # 更新备槽位Pod的route标签为alt
          kubectl patch pods -l app={{ template "blue-green-deploy.name" . }},slot={{ if eq .Values.productionSlot "blue" }}green{{ else }}blue{{ end }} -p '{"metadata":{"labels":{"route":"alt"}}}'

步骤2：创建权限配置（RBAC） #

在templates目录下创建rbac.yaml，赋予Job修改Pod标签的权限：

apiVersion: v1
kind: ServiceAccount
metadata:
  name: {{ include "blue-green-deploy.fullname" . }}-patch-sa
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: {{ include "blue-green-deploy.fullname" . }}-patch-role
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["patch", "get", "list"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: {{ include "blue-green-deploy.fullname" . }}-patch-rb
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: {{ include "blue-green-deploy.fullname" . }}-patch-role
subjects:
- kind: ServiceAccount
  name: {{ include "blue-green-deploy.fullname" . }}-patch-sa
  namespace: {{ .Release.Namespace }}

步骤3：调整Deployment模板（初始标签） #

确保首次部署时Pod的route标签正确：

{{- define "blue-green-deploy.deployment" -}}
{{- $currSlot := (pluck .currSlot .Values | first) }}
{{- $isProduction := eq .currSlot .Values.productionSlot }}
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "blue-green-deploy.fullname" . }}-{{ .currSlot }}
  labels:
    release: {{ .Release.Name }}
    chart: "{{ .Chart.Name }}-{{ .Chart.Version }}"
    app: {{ template "blue-green-deploy.name" . }}
    version: {{ $currSlot.appVersion | quote }}
    slot: {{ .currSlot }}
    route: {{ if $isProduction }}primary{{ else }}alt{{ end }}
spec:
  template:
    metadata:
      labels:
        release: {{ .Release.Name }}
        app: {{ template "blue-green-deploy.name" . }}
        version: {{ $currSlot.appVersion | quote }}
        slot: {{ .currSlot }}
        route: {{ if $isProduction }}primary{{ else }}alt{{ end }}
    ...
{{- end }}

步骤4：执行路由切换 #

运行原helm upgrade命令，Hook会自动触发Job修改Pod标签，全程无需重建Pod。

内容的提问来源于stack exchange，提问作者CodeChimp