Istio upgrade from 1.4 to 1.5 - kubernetes

Question

We have installed istion-1.4.0 from istio-demo.yml file by running the following command on k8s cluster - 1.15.1
kubectl apply -f istio-demo.yml
Now we need to upgrade our istio from 1.4.0 to 1.5.0 and as per my understanding its not straight forward, due to changes in istio components ( introducing of istiod and removing citadel,galley,policy & telemetry).
How can i move from kubectl to istoctl so that my future upgrade to istio in-line with.??

Answer 1

As I mentioned in comments I have followed a theme on istio discuss about upgrade created by#laurentiuspurba.
I have changed it a little for your use case, so an upgrade from 1.4 to 1.5.
Take a look at below steps to follow.
1.Follow istio documentation and install istioctl 1.4 and 1.5 with:
curl -L https://istio.io/downloadIstio | ISTIO_VERSION=1.4.0 sh -
curl -L https://istio.io/downloadIstio | ISTIO_VERSION=1.5.0 sh -
2.Add the istioctl 1.4 to your path
cd istio-1.4.0
export PATH=$PWD/bin:$PATH
3.Install istio 1.4
istioctl manifest generate > $HOME/generated-manifest.yaml
kubectl create namespace istio-system
kubectl apply -f generated-manifest.yaml
4.Check if everything works correct.
kubectl get pod -n istio-system
kubectl get svc -n istio-system
istioctl version
5.Add the istioctl 1.5 to your path
cd istio-1.5.0
export PATH=$PWD/bin:$PATH
6.Install istio operator for future upgrade.
istioctl operator init
7.Prepare IstioOperator.yaml
nano IstioOperator.yaml
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
metadata:
namespace: istio-system
name: example-istiocontrolplane
spec:
profile: default
tag: 1.5.0
8.Before the upgrade use below commands
kubectl -n istio-system delete service/istio-galley deployment.apps/istio-galley
kubectl delete validatingwebhookconfiguration.admissionregistration.k8s.io/istio-galley
9.Upgrade from 1.4 to 1.5 with istioctl upgrade and prepared IstioOperator.yaml
istioctl upgrade -f IstioOperator.yaml
10.After the upgrade use below commands
kubectl -n istio-system delete deployment istio-citadel istio-galley istio-pilot istio-policy istio-sidecar-injector istio-telemetry
kubectl -n istio-system delete service istio-citadel istio-policy istio-sidecar-injector istio-telemetry
kubectl -n istio-system delete horizontalpodautoscaler.autoscaling/istio-pilot horizontalpodautoscaler.autoscaling/istio-telemetry
kubectl -n istio-system delete pdb istio-citadel istio-galley istio-pilot istio-policy istio-sidecar-injector istio-telemetry
kubectl -n istio-system delete deployment istiocoredns
kubectl -n istio-system delete service istiocoredns
11.Check if everything works correct.
kubectl get pod -n istio-system
kubectl get svc -n istio-system
istioctl version
12.I have deployed a bookinfo app to check if everything work correct.
kubectl label namespace default istio-injection=enabled
kubectl apply -f samples/bookinfo/platform/kube/bookinfo.yaml
kubectl apply -f samples/bookinfo/networking/bookinfo-gateway.yaml
13.Results
curl -v xx.xx.xxx.xxx/productpage | grep HTTP
HTTP/1.1 200 OK
istioctl version
client version: 1.5.0
control plane version: 1.5.0
data plane version: 1.5.0 (8 proxies)
Hope you find this useful. If you have any questions let me know.