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Diff for: ‎package-managers/helm/helm-demo.md

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

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