Blue-Green Deployment using Helm Charts on Kubernetes

Installation

Prerequisites

• Install Helm3

$ curl https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3 > get_helm.sh
$ chmod 700 get_helm.sh
$ ./get_helm.sh

• Install Istio

$ wget https://github.com/istio/istio/releases/download/1.9.3/istio-1.9.3-osx.tar.gz
$ tar zxvf istio-1.9.3-osx.tar.gz
$ cd istio-1.9.3
$ helm install istio-base manifests/charts/base -n istio-system
$ helm install istiod manifests/charts/istio-control/istio-discovery -n istio-system
$ helm install istio-ingress manifests/charts/gateways/istio-ingress -n istio-system

• Create new namespace - my-app

$ kubectl create namespace my-app

• Add label for Istio auto injection

$ kubectl label namespace my-app istio.io/rev=1-9-3

• Config default namespace to my-app

$ kubectl config set-context --current --namespace my-app

Running for blue-green deployment

• Change directory to the root folder of blue-green helm chart

$ cd blue-green

• The first time deploy the blue and green deployment with the version "1.0" for both slots by the Helm install command and than switch traffic to blue

$ helm install deploy-test . --namespace=my-app --set blue.enabled=true --set blue.timestamp="$(date '+%Y-%m-%d %H:%M:%S')" --set blue.appVersion="1.0" --set green.timestamp="$(date '+%Y-%m-%d %H:%M:%S')" --set green.appVersion="1.0" --set productionSlot=blue --debug

• Deploy the green deployment with the new version "xx.xx" by the Helm upgrade command

# You can define new version for this release to replace "xx.xx"
$ ./deployBlueOrGreen.sh green xx.xx

• Checkout rolling update status is ready

$ kubectl rollout status deployments/bg-deploy-green -n my-app
deployment "deploy-test-my-app-green" successfully rolled out

• Switch the traffic to green

$ ./switchTraffic.sh green

• Repeat the steps for upgrading the blue deployment with new version again

# You can define new version for this release to replace "xx.xx"
$ ./deployBlueOrGreen.sh blue xx.xx
$ kubectl rollout status deployments/bg-deploy-blue -n my-app
$ ./moveTraffic.sh blue

Running for automatic blue-green deployment

• Port forward to the Istio ingress controller

kubectl port-forward $(kubectl get pods --selector=istio=ingressgateway -n istio-system --no-headers -o custom-columns=NAME:.metadata.name) 8080:8080

• Add a record into your /etc/hosts

127.0.0.1	deploy-test.example.org

• Open your web browser and open the url with http://deploy-test.example.org:8080
• You can monitor automatic blue-green deployment by the following command:

# You can define new version for this release to replace "xx.xx"
$ ./autoDeployBlueOrGreen.sh xx.xx

• Monitor the website changes