Add blue-green deployment example (#19)

blue-green/.helmignore

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+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj

blue-green/Chart.yaml

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+apiVersion: v1
+appVersion: "1.0"
+description: A Helm chart for Kubernetes
+name: helm-guestbook
+version: 0.1.0

blue-green/README.md

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+# Blue Green
+
+The blue green strategy is not supported by built-in Kubernetes Deployment but available via third-party Kubernetes controller.
+This example demonstrates how to implement blue-green deployment via [Argo Rollouts](https://github.com/argoproj/argo-rollouts):
+
+1. Install Argo Rollouts controller: https://github.com/argoproj/argo-rollouts#installation
+2. Create a sample application and sync it.
+
+```
+argocd app create --name blue-green --repo https://github.com/argoproj/argocd-example-apps --dest-server https://kubernetes.default.svc --dest-namespace default --path blue-green && argocd app sync blue-green
+```
+
+Once the application is synced you can access it using `blue-green-helm-guestbook` service.
+
+3. Change image version parameter to trigger blue-green deployment process:
+
+```
+argocd app set blue-green -p image.tag=0.2 && argocd app sync blue-green
+```
+
+Now application runs `ks-guestbook-demo:0.1` and `ks-guestbook-demo:0.2` images simultaneously.
+The `ks-guestbook-demo:0.2` is still considered `blue` available only via preview service `blue-green-helm-guestbook-preview`.
+
+4. Promote `ks-guestbook-demo:0.2` to `green` by patching `Rollout` resource:
+
+```
+argocd app patch-resource blue-green --kind Rollout --resource-name blue-green-helm-guestbook --patch '{ "spec": { "paused": false } }' --patch-type 'application/merge-patch+json'
+```
+
+This promotes `ks-guestbook-demo:0.2` to `green` status and `Rollout` deletes old replica which runs `ks-guestbook-demo:0.1`.

blue-green/templates/NOTES.txt

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+1. Get the application URL by running these commands:
+{{- if .Values.ingress.enabled }}
+{{- range .Values.ingress.hosts }}
+  http{{ if $.Values.ingress.tls }}s{{ end }}://{{ . }}{{ $.Values.ingress.path }}
+{{- end }}
+{{- else if contains "NodePort" .Values.service.type }}
+  export NODE_PORT=$(kubectl get --namespace {{ .Release.Namespace }} -o jsonpath="{.spec.ports[0].nodePort}" services {{ template "helm-guestbook.fullname" . }})
+  export NODE_IP=$(kubectl get nodes --namespace {{ .Release.Namespace }} -o jsonpath="{.items[0].status.addresses[0].address}")
+  echo http://$NODE_IP:$NODE_PORT
+{{- else if contains "LoadBalancer" .Values.service.type }}
+     NOTE: It may take a few minutes for the LoadBalancer IP to be available.
+           You can watch the status of by running 'kubectl get svc -w {{ template "helm-guestbook.fullname" . }}'
+  export SERVICE_IP=$(kubectl get svc --namespace {{ .Release.Namespace }} {{ template "helm-guestbook.fullname" . }} -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
+  echo http://$SERVICE_IP:{{ .Values.service.port }}
+{{- else if contains "ClusterIP" .Values.service.type }}
+  export POD_NAME=$(kubectl get pods --namespace {{ .Release.Namespace }} -l "app={{ template "helm-guestbook.name" . }},release={{ .Release.Name }}" -o jsonpath="{.items[0].metadata.name}")
+  echo "Visit http://127.0.0.1:8080 to use your application"
+  kubectl port-forward $POD_NAME 8080:80
+{{- end }}

blue-green/templates/_helpers.tpl

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+{{/* vim: set filetype=mustache: */}}
+{{/*
+Expand the name of the chart.
+*/}}
+{{- define "helm-guestbook.name" -}}
+{{- default .Chart.Name .Values.nameOverride | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+
+{{/*
+Create a default fully qualified app name.
+We truncate at 63 chars because some Kubernetes name fields are limited to this (by the DNS naming spec).
+If release name contains chart name it will be used as a full name.
+*/}}
+{{- define "helm-guestbook.fullname" -}}
+{{- if .Values.fullnameOverride -}}
+{{- .Values.fullnameOverride | trunc 63 | trimSuffix "-" -}}
+{{- else -}}
+{{- $name := default .Chart.Name .Values.nameOverride -}}
+{{- if contains $name .Release.Name -}}
+{{- .Release.Name | trunc 63 | trimSuffix "-" -}}
+{{- else -}}
+{{- printf "%s-%s" .Release.Name $name | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+{{- end -}}
+{{- end -}}
+
+{{/*
+Create chart name and version as used by the chart label.
+*/}}
+{{- define "helm-guestbook.chart" -}}
+{{- printf "%s-%s" .Chart.Name .Chart.Version | replace "+" "_" | trunc 63 | trimSuffix "-" -}}
+{{- end -}}

blue-green/templates/rollout.yaml

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+apiVersion: argoproj.io/v1alpha1
+kind: Rollout
+metadata:
+  name: {{ template "helm-guestbook.fullname" . }}
+  labels:
+    app: {{ template "helm-guestbook.name" . }}
+    chart: {{ template "helm-guestbook.chart" . }}
+    release: {{ .Release.Name }}
+    heritage: {{ .Release.Service }}
+spec:
+  replicas: {{ .Values.replicaCount }}
+  revisionHistoryLimit: 3
+  selector:
+    matchLabels:
+      app: {{ template "helm-guestbook.name" . }}
+      release: {{ .Release.Name }}
+  strategy:
+    blueGreen:
+      activeService: {{ template "helm-guestbook.fullname" . }}
+      previewService: {{ template "helm-guestbook.fullname" . }}-preview
+  template:
+    metadata:
+      labels:
+        app: {{ template "helm-guestbook.name" . }}
+        release: {{ .Release.Name }}
+    spec:
+      containers:
+        - name: {{ .Chart.Name }}
+          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
+          ports:
+            - name: http
+              containerPort: 80
+              protocol: TCP
+          livenessProbe:
+            httpGet:
+              path: /
+              port: http
+          readinessProbe:
+            httpGet:
+              path: /
+              port: http
+          resources:
+{{ toYaml .Values.resources | indent 12 }}
+    {{- with .Values.nodeSelector }}
+      nodeSelector:
+{{ toYaml . | indent 8 }}
+    {{- end }}
+    {{- with .Values.affinity }}
+      affinity:
+{{ toYaml . | indent 8 }}
+    {{- end }}
+    {{- with .Values.tolerations }}
+      tolerations:
+{{ toYaml . | indent 8 }}
+    {{- end }}

blue-green/templates/services.yaml

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+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ template "helm-guestbook.fullname" . }}
+  labels:
+    app: {{ template "helm-guestbook.name" . }}
+    chart: {{ template "helm-guestbook.chart" . }}
+    release: {{ .Release.Name }}
+    heritage: {{ .Release.Service }}
+spec:
+  type: {{ .Values.service.type }}
+  ports:
+    - port: {{ .Values.service.port }}
+      targetPort: http
+      protocol: TCP
+      name: http
+  selector:
+    app: {{ template "helm-guestbook.name" . }}
+    release: {{ .Release.Name }}
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: {{ template "helm-guestbook.fullname" . }}-preview
+  labels:
+    app: {{ template "helm-guestbook.name" . }}
+    chart: {{ template "helm-guestbook.chart" . }}
+    release: {{ .Release.Name }}
+    heritage: {{ .Release.Service }}
+spec:
+  type: {{ .Values.service.type }}
+  ports:
+    - port: {{ .Values.service.port }}
+      targetPort: http
+      protocol: TCP
+      name: http
+  selector:
+    app: {{ template "helm-guestbook.name" . }}
+    release: {{ .Release.Name }}

blue-green/values.yaml

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+# Default values for helm-guestbook.
+# This is a YAML-formatted file.
+# Declare variables to be passed into your templates.
+
+replicaCount: 1
+
+image:
+  repository: gcr.io/heptio-images/ks-guestbook-demo
+  tag: 0.1
+  pullPolicy: IfNotPresent
+
+service:
+  type: ClusterIP
+  port: 80
+
+ingress:
+  enabled: false
+  annotations: {}
+    # kubernetes.io/ingress.class: nginx
+    # kubernetes.io/tls-acme: "true"
+  path: /
+  hosts:
+    - chart-example.local
+  tls: []
+  #  - secretName: chart-example-tls
+  #    hosts:
+  #      - chart-example.local
+
+resources: {}
+  # We usually recommend not to specify default resources and to leave this as a conscious
+  # choice for the user. This also increases chances charts run on environments with little
+  # resources, such as Minikube. If you do want to specify resources, uncomment the following
+  # lines, adjust them as necessary, and remove the curly braces after 'resources:'.
+  # limits:
+  #  cpu: 100m
+  #  memory: 128Mi
+  # requests:
+  #  cpu: 100m
+  #  memory: 128Mi
+
+nodeSelector: {}
+
+tolerations: []
+
+affinity: {}