Merge pull request Tikam02#180 from siwar9/helm-demo

Create helm-demo.md
zaki-faani · Nov 3, 2022 · d5ab502 · d5ab502
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diff --git a/package-managers/helm/helm-demo.md b/package-managers/helm/helm-demo.md
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+## Helm demo
+*This demo will user the ingress on bare-metal using the Nginx Ingress Controller and metalLB.*
+
+In my `helm-demo` folder, I have the `templates` directory and the `Chart` and `values` YAML files :
+```bash
+k8s-master@master:~/helm-demo$ ls
+Chart.yaml  templates  values.yaml
+```
+Inside the Chart.yaml file :
+```YAML
+name: my-first-demo
+version: 1.0.0
+description: easy helm demo
+maintainers:
+- name: Siwar
+```
+This is the metadata to describe each deployment.
+
+Now inside the templates directory :
+```bash
+k8s-master@master:~/helm-demo/templates$ ls
+deployment.yaml  ingress.yaml  service.yaml
+```
+The depoyment.yaml file contains a simple nginx deployment :
+```YAML
+apiVersion: apps/v1
+kind: Deployment
+metadata: 
+  name: my-nginx-deployment
+spec:
+  selector:
+    matchLabels:
+      app: nginx
+  replicas: 3
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.14.2
+        ports:
+        - containerPort: 80
+
+```
+And the service.yaml file :
+``` YAML
+apiVersion: v1
+kind: Service
+metadata: 
+  name: my-nginx-service
+spec:
+  selector:
+    app: nginx
+  ports:
+  - name: main
+    protocol: TCP
+    port: 80
+```
+And the ingress.yaml :
+```YAML
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: my-nginx-ingress
+  annotations:
+    nginx.ingress.kubernetes.io/rewrite-target: /
+    http.port: "443"
+spec:
+  ingressClassName: nginx
+  rules:
+  - http:
+      paths:
+      - path: /testpath
+        pathType: Prefix
+        backend:
+          service:
+            name: my-nginx-service
+            port:
+              number: 80
+
+```
+We're exposing port 443 on our ingress.
+
+Next is `helm install`:
+```bash 
+k8s-master@master:~$ helm install --generate-name helm-demo/
+NAME: helm-demo-1660310990
+LAST DEPLOYED: Fri Aug 12 06:29:50 2022
+NAMESPACE: default
+STATUS: deployed
+REVISION: 1
+TEST SUITE: None
+```
+So now with Helm and thanks to only one command line tool `helm install`, we were able to deploy our app very easily and very fast.
+```bash
+k8s-master@master:~$ kubectl get all
+NAME                                      READY   STATUS              RESTARTS   AGE
+pod/my-nginx-deployment-9456bbbf9-c74rs   0/1     ContainerCreating   0          11s
+pod/my-nginx-deployment-9456bbbf9-k4cdb   0/1     ContainerCreating   0          11s
+pod/my-nginx-deployment-9456bbbf9-mm7dm   0/1     ContainerCreating   0          11s
+
+NAME                       TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
+service/kubernetes         ClusterIP   10.96.0.1        <none>        443/TCP   22m
+service/my-nginx-service   ClusterIP   10.100.146.193   <none>        80/TCP    11s
+
+NAME                                  READY   UP-TO-DATE   AVAILABLE   AGE
+deployment.apps/my-nginx-deployment   0/3     3            0           11s
+
+NAME                                            DESIRED   CURRENT   READY   AGE
+replicaset.apps/my-nginx-deployment-9456bbbf9   3         3         0       11s
+```
+We can check our app running in the browser using the ingress ip `192.168.1.240` and specifying the path `/testpath`:
+
+<img src="nginx.png" width=50% height=50%>
+
+The usual way to do this with kubectl is by executing the `kubectl apply` command line for every resource.
+
+Another important feature in Helm are placeholders!
+so if we look at another deployment.yaml file for example :
+```Yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata: 
+  name: my-nginx-deployment
+spec:
+  selector:
+    matchLabels:
+      app: nginx
+  replicas: {{.Values.scale}}
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+      - name: nginx
+        image: nginx:1.14.2
+        ports:
+        - containerPort: 80
+```
+The `{{.Values.scale}}`placeholder makes it possible to modify the configuration without having to edit the actual manifest file every time.
+
+So whatever the value of scale is in `values.yaml` file is going to be the value of the configuration file.
+
+The `values.yaml` file :
+```bash
+k8s-master@master:~/helming-once-more$ cat values.yaml
+scale: 3
+```
+
+And now let's install our app again :
+```bash
+k8s-master@master:~$ helm install another-demo helming-once-more/
+NAME: another-demo
+LAST DEPLOYED: Fri Aug 12 11:48:53 2022
+NAMESPACE: default
+STATUS: deployed
+REVISION: 1
+TEST SUITE: None
+```
+Just to check that we have our pods up and running :
+```bash
+k8s-master@master:~$ kubectl get pods
+NAME                                  READY   STATUS    RESTARTS   AGE
+my-nginx-deployment-9456bbbf9-mx45n   1/1     Running   0          3m9s
+my-nginx-deployment-9456bbbf9-rqkmw   1/1     Running   0          3m9s
+my-nginx-deployment-9456bbbf9-tl4wj   1/1     Running   0          3m9s
+```
+So thanks to the scale value in the values.yaml file, we now have 3 pods.
+
+For some reason or another, we needed to scale up our up :
+```bash 
+k8s-master@master:~$ helm upgrade --set scale=5 another-demo ./helming-once-more/
+Release "another-demo" has been upgraded. Happy Helming!
+NAME: another-demo
+LAST DEPLOYED: Fri Aug 12 11:55:14 2022
+NAMESPACE: default
+STATUS: deployed
+REVISION: 2
+TEST SUITE: None
+```
+```bash 
+k8s-master@master:~$ kubectl get pod
+NAME                                  READY   STATUS    RESTARTS   AGE
+my-nginx-deployment-9456bbbf9-7ddlm   1/1     Running   0          95s
+my-nginx-deployment-9456bbbf9-mx45n   1/1     Running   0          8m9s
+my-nginx-deployment-9456bbbf9-rqkmw   1/1     Running   0          8m9s
+my-nginx-deployment-9456bbbf9-tl4wj   1/1     Running   0          8m9s
+my-nginx-deployment-9456bbbf9-tpsqv   1/1     Running   0          96s
+```
+
+To finish off, we will delete our app :
+```bash 
+k8s-master@master:~$ helm list
+NAME           NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                   APP VERSION
+another-demo    default         2               2022-08-12 11:55:14.913503686 -0700 PDT deployed        another-demo-1.0.0
+k8s-master@master:~$ helm uninstall another-demo
+release "another-demo" uninstalled
+```