kubernetes rolling update using helm - kubernetes

Question

I am new to Helm. I have installed Minikube & Helm on my windows system. I am able create pods using Helm and see deployment,pods & replicaset in dashboard.
I want to do rolling update using Helm. Guide me how to do rolling update in K8s using Helm.
Creating Tomcat pod using Helm
helm create hello-world
Changed image name and deployment name in deployment.yaml
kind: Deployment
metadata:
name: mytomcat
spec:
containers:
- name: {{ .Chart.Name }}
image: tomcat
Install
helm install hello-world
NAME: whopping-dolphin
LAST DEPLOYED: Wed Aug 30 21:38:42 2017
NAMESPACE: default
STATUS: DEPLOYED
RESOURCES:
==> v1/Service
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
whopping-dolphin-hello-world 10.0.0.178 <none> 80/TCP 0s
==> v1beta1/Deployment
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
mytomcat 1 1 1 0 0s
NOTES:
1. Get the application URL by running these commands:
export POD_NAME=$(kubectl get pods --namespace default -l "app=hello-world,release=whopping-dolphin" -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
I see mytomcat deployment and pod mytomcat-2768693561-hd2hd in dashboard.
Now I would like to give command which will delete my current deployment & pod in k8s and it should create new deployment and pod.
It will be helpful if I get sample commands and yaml.

Answer 1

Below command is working fine for Rolling update.
First time it will be install
next time it will be upgrade
helm upgrade --install tom-release --set appName=mytomcatcon
hello-world
tom-release is my release name and passing runtime values to helm chart using --set option