Release lab lesson 9

README.org

@@ -65,4 +65,10 @@ As a general rule, if the exercise contains only the =README.org=, you should pr
 - [[file:e28][Exercise 28 - Namespaces]]
 - [[file:e29][Exercise 29 - Labels and Selectors]]
 - [[file:e30][Exercise 30 - Install k8s Dashboard]]
-- [[file:e31][Exercise 31 - ConfigMaps & Secrets]]
\ No newline at end of file
+- [[file:e31][Exercise 31 - ConfigMaps & Secrets]]
+* Lab09_2022053
+- [[file:e32][Exercise 32 - Volumes]]
+- [[file:e33][Exercise 33 - Install Helm]]
+- [[file:e34][Exercise 34 - NGINX Ingress Controller]]
+- [[file:e35][Exercise 35 - Ingress resource usage]]
+- [[file:e36][Exercise 36 - Pod placement]]
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e27/README.org

@@ -6,7 +6,7 @@
     Deployment (of course is the ReplicaSet which scale) created
     during previous exercise to 6 replicas. While scaling it, look at the 
     workload in the cluster and especially paying attention on how the
-    scheduler spread the workload. Then have a look at how the Service
+    scheduler distribute the workload. Then have a look at how the Service
     resource has been modified by Kubernetes and finally try to access
     the server many times.
 

e32/README.org

+* Exercise 32 - Volumes
+  - Time :: 15 minutes
+    - 6 minutes: /Try by yourself/
+    - 9 minutes: /Check, Verify, Ask/
+  - Description :: Create two webservers: the first with ephemeral
+    storage and the second with persistent storage, finally then check
+    the differences. In the second case the webserver =document-root=
+    is exposed via a Volume.
+
+    There will be a built in storage class so that I can deploy
+    applications that request persistent volume claims.
+
+    Ensure that modification on the document root are persistent
+    across pod restarts: If my pod restarts I want that pod to be
+    scheduled such that the persistent volume claim is available again
+    to it.
+
+    This ensures that if I have to restart my pod will always come
+    back with access to the same data.
+
+* Solutions and Instructions
+  Inspect the default solution to manage Volumes in kind: [[https://github.com/rancher/local-path-provisioner][Ranchers
+  local path persistent storage solution]].
+
+  Check which is the default StorageClass
+  #+BEGIN_SRC sh
+  kubectl get storageclass
+  #+END_SRC
+
+  This solution relies on a deployment of some resources in the
+  =local-path-storage= namespace, inspect them
+  #+BEGIN_SRC sh
+  kubectl get all -n local-path-storage
+  #+END_SRC
+
+  *Note:* /Note the way this storage solution works: When a pvc is
+  created the persistent volume will be dynamically created on the
+  node that the pod is scheduled to. This means that in the case of
+  pod failure or restart the pod will only be scheduled to the node
+  where the persistent volume was allocated. If that node is not
+  available then the pod will not schedule./
+
+  *Create the first webserver - with ephemeral storage*
+
+  Create an ephemeral webserver
+  #+BEGIN_SRC sh
+  kubectl create deploy --image=nginx ws-ephemeral
+  #+END_SRC
+
+  Expose this webserver via a =Service=
+  #+BEGIN_SRC sh
+  kubectl expose deploy ws-ephemeral --type=NodePort --port=80
+  #+END_SRC
+
+  Get the IP of the master node
+  #+BEGIN_SRC sh
+  MASTER_IP=`docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $USER-control-plane`
+  #+END_SRC
+
+  Get the random NodePort
+  #+BEGIN_SRC sh
+  RANDOM_PORT_EPH=`kubectl get svc ws-ephemeral -o jsonpath='{.spec.ports[0].nodePort}'`
+  #+END_SRC
+
+  Test access from the Lab Virtual Machine or from your browser
+  #+BEGIN_SRC sh
+  echo "I can reach the service using this URL: http://$MASTER_IP:$RANDOM_PORT_EPH"
+  curl http://$MASTER_IP:$RANDOM_PORT_EPH
+  #+END_SRC
+
+  Overwrite the main nginx page
+  #+BEGIN_SRC sh
+  WS_EPH=`kubectl get pod -l app=ws-ephemeral -o jsonpath='{.items[0].metadata.name}'`
+  kubectl cp index.html $WS_EPH:/usr/share/nginx/html/index.html
+  #+END_SRC
+
+  Check the service again. Default page is customized
+  #+BEGIN_SRC sh
+  curl http://$MASTER_IP:$RANDOM_PORT_EPH
+  #+END_SRC
+
+  Delete the pod
+  #+BEGIN_SRC sh
+  kubectl delete pod -l app=ws-ephemeral
+  #+END_SRC
+
+  Check the service again (waith for the pod the be
+  rescheduled). Default page is back to NGINX default one
+  #+BEGIN_SRC sh
+  curl http://$MASTER_IP:$RANDOM_PORT_EPH
+  #+END_SRC
+
+  *Create the second webserver - with persistent storage*
+
+  Inspect =PersistentVolumes= and =PersistentVolumeClaims=
+  #+BEGIN_SRC sh
+  kubectl get pv
+  kubectl get pvc
+  #+END_SRC
+
+  Check the [[file:pvc.yaml][resource]] and create a PersistentVolumeClaim
+  #+BEGIN_SRC sh
+  kubectl create -f pvc.yaml
+  #+END_SRC
+
+  Check again the =PersistentVolumeClaims=
+  #+BEGIN_SRC sh
+  kubectl get pvc
+  #+END_SRC
+
+  Check the [[file:ws-persistent.yaml][resource]] and create a persistent webserver
+  #+BEGIN_SRC sh
+  kubectl create -f ws-persistent.yaml
+  #+END_SRC
+
+  Inspect again the =PersistentVolumes= and =PersistentVolumeClaims=
+  #+BEGIN_SRC sh
+  kubectl get pv
+  kubectl get pvc
+  #+END_SRC
+
+  Expose this webserver via a =Service=
+  #+BEGIN_SRC sh
+  kubectl expose deploy ws-persistent --type=NodePort --port=80
+  #+END_SRC
+
+  Get the random NodePort
+  #+BEGIN_SRC sh
+  RANDOM_PORT_PER=`kubectl get svc ws-persistent -o jsonpath='{.spec.ports[0].nodePort}'`
+  #+END_SRC
+
+  Test access from the Lab Virtual Machine or from your browser, the
+  service reply with =403= because the document root is empty and we
+  cannot list =/= by default.
+  #+BEGIN_SRC sh
+  echo "I can reach the service using this URL: http://$MASTER_IP:$RANDOM_PORT_PER"
+  curl http://$MASTER_IP:$RANDOM_PORT_PER
+  #+END_SRC
+
+  Let's create a default page by copying an =index.html= page into the NGINX document root
+  #+BEGIN_SRC sh
+  WS_PER=`kubectl get pod -l app=ws-persistent -o jsonpath='{.items[0].metadata.name}'`
+  kubectl cp index.html $WS_PER:/usr/share/nginx/html/index.html
+  #+END_SRC
+
+  Check the service again. Default page is now present and it is customized by us
+  #+BEGIN_SRC sh
+  curl http://$MASTER_IP:$RANDOM_PORT_PER
+  #+END_SRC
+
+  Delete the pod
+  #+BEGIN_SRC sh
+  kubectl delete pod -l app=ws-persistent
+  #+END_SRC
+
+  Check the service again. Default page is customized also in the new pod
+  #+BEGIN_SRC sh
+  curl http://$MASTER_IP:$RANDOM_PORT_PER
+  #+END_SRC
+
+  - How can we check the file of the persistent storage on the k8s node?
+    Tip: use =docker exec=
+  - Inspect the =PersistentVolume=. How is it attached to the chosen worker node?
+    Tip: Inspect the =PersistentVolume= manifest created by the
+    provisioner

e32/index.html

+<!DOCTYPE html>
+<html>
+<head>
+	<title>Custom webserver v1</title>
+</head>
+<body>
+<h1>Custom webserver v1</h1>
+<h2>Absolutely !!! This is the best course in UniTN... ;D</h2>
+</body>
+</html>
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e32/pvc.yaml

+apiVersion: v1
+kind: PersistentVolumeClaim
+metadata:
+  name: mypvc
+  labels:
+    # insert any desired labels to identify your claim
+    app: mypvc
+spec:
+  storageClassName: standard
+  accessModes:
+    - ReadWriteOnce
+  resources:
+    requests:
+      # The amount of the volume's storage to request
+      storage: 2Gi

e32/ws-persistent.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: ws-persistent
+  namespace: default
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: ws-persistent
+  template:
+    metadata:
+      labels:
+        app: ws-persistent
+    spec:
+      containers:
+      - name: ws
+        image: nginx
+        imagePullPolicy: Always
+        ports:
+        - containerPort: 80
+        volumeMounts:
+        - name: volume
+          mountPath: /usr/share/nginx/html/
+      volumes:
+      - name: volume
+        persistentVolumeClaim:
+          claimName: mypvc

e33/README.org

+* Exercise 33 - Helm installation
+  - Time :: 10 minutes
+    - 4 minutes: /Try by yourself/
+    - 6 minutes: /Check, Verify, Ask/
+  - Description :: Install Helm and practice with basic commands
+* Solutions and Instructions
+
+  *Please note:* If you are in a group, commands marked with * *must*
+  be done by one member only
+
+  Install Helm (*)
+  #+BEGIN_SRC sh
+  cd $HOME
+  curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/master/scripts/get-helm-3
+  chmod 700 get_helm.sh
+  ./get_helm.sh
+  #+END_SRC
+
+  Verify Helm installation
+  #+BEGIN_SRC sh
+  helm version
+  #+END_SRC
+
+  Add a repo
+  #+BEGIN_SRC sh
+  helm repo add stable https://charts.helm.sh/stable
+  #+END_SRC
+
+  Search for charts in the repo
+  #+BEGIN_SRC sh
+  helm search repo stable
+  #+END_SRC
+
+  Update the repo
+  #+BEGIN_SRC sh
+  helm repo update
+  #+END_SRC
+
+  Install a chart
+  #+BEGIN_SRC sh
+  helm install $USER-mysql stable/mysql
+  #+END_SRC
+
+  List all installed charts
+  #+BEGIN_SRC sh
+  helm list
+  #+END_SRC
+
+  Check status of a chart
+  #+BEGIN_SRC sh
+  helm status $USER-mysql
+  kubectl get pod
+  #+END_SRC
+
+  Uninstall a chart
+  #+BEGIN_SRC sh
+  helm uninstall $USER-mysql
+  kubectl get pod
+  #+END_SRC

e34/README.org

+* Exercise 34 - NGINX Ingress Controller
+  - Time :: 10 minutes
+    - 4 minutes: /Try by yourself/
+    - 6 minutes: /Check, Verify, Ask/
+  - Description :: Install the NGINX Ingress Controller in your kind cluster.
+* Solutions and Instructions
+  Free up some resources
+  #+BEGIN_SRC sh
+  kubectl delete all --all
+  #+END_SRC
+
+  Install the NGINX Ingress controller
+  #+BEGIN_SRC sh
+  kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/provider/kind/deploy.yaml
+  #+END_SRC
+
+  Enable a node where the NGINX Ingress controller should run
+  #+BEGIN_SRC sh
+  kubectl label node $USER-control-plane ingress-ready=true
+  #+END_SRC
+
+  Wait for the Ingress Controller to be ready
+  #+BEGIN_SRC sh
+  kubectl wait --namespace ingress-nginx \
+  --for=condition=ready pod \
+  --selector=app.kubernetes.io/component=controller \
+  --timeout=30s
+  #+END_SRC
+
+  Check the controller is running
+  #+BEGIN_SRC sh
+  kubectl get pod -n ingress-nginx
+  #+END_SRC
+
+  Check events in the controller creation
+  #+BEGIN_SRC sh
+  kubectl describe pod -l app.kubernetes.io/name=ingress-nginx -n ingress-nginx
+  #+END_SRC

e35/README.org

+* Exercise 35 - Ingress resource usage
+  - Time :: 10 minutes
+    - 4 minutes: /Try by yourself/
+    - 6 minutes: /Check, Verify, Ask/
+  - Description :: Create two services which prints different
+    strings. Expose them via two different Services and finally create
+    an Ingress rule that forward the traffic to the right Pod
+    depending on the HTTP path.
+* Solutions and Instructions
+  Free-up the cluster resources
+  #+BEGIN_SRC sh
+  kubectl delete all --all
+  #+END_SRC
+
+  Inspect and install the =foo= pod, see manifest [[file:foo.yaml][here]]
+  #+BEGIN_SRC sh
+  kubectl create -f foo.yaml
+  #+END_SRC
+
+  Inspect and install the =bar= pod, see manifest [[file:bar.yaml][here]]
+  #+BEGIN_SRC sh
+  kubectl create -f bar.yaml
+  #+END_SRC
+
+  Inspect and install the =Ingress= resource, see manifest [[file:ingress.yaml][here]]
+  #+BEGIN_SRC sh
+  kubectl create -f ingress.yaml
+  #+END_SRC
+
+  Check the resources are deployed
+  #+BEGIN_SRC sh
+  kubectl get pod -o wide
+  kubectl get svc
+  kubectl get ingress
+  #+END_SRC
+
+  Get the master IP
+  #+BEGIN_SRC sh
+  MASTER_IP=`docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $USER-control-plane`
+  #+END_SRC
+
+  Check the =Ingress= rules are working as expected
+  #+BEGIN_SRC sh
+  curl http://$MASTER_IP/foo
+  curl http://$MASTER_IP/bar
+  curl http://$MASTER_IP/noo
+  #+END_SRC

e35/bar.yaml

+kind: Pod
+apiVersion: v1
+metadata:
+  name: bar-app
+  labels:
+    app: bar
+spec:
+  containers:
+  - name: bar-app
+    image: hashicorp/http-echo:0.2.3
+    args:
+    - "-text=bar"
+---
+kind: Service
+apiVersion: v1
+metadata:
+  name: bar-service
+spec:
+  selector:
+    app: bar
+  ports:
+  # Default port used by the image
+  - port: 5678
\ No newline at end of file

e35/foo.yaml

+kind: Pod
+apiVersion: v1
+metadata:
+  name: foo-app
+  labels:
+    app: foo
+spec:
+  containers:
+  - name: foo-app
+    image: hashicorp/http-echo:0.2.3
+    args:
+    - "-text=foo"
+---
+kind: Service
+apiVersion: v1
+metadata:
+  name: foo-service
+spec:
+  selector:
+    app: foo
+  ports:
+  # Default port used by the image
+  - port: 5678
\ No newline at end of file

e35/ingress.yaml

+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: example-ingress
+spec:
+  rules:
+  - http:
+      paths:
+      - path: /foo
+        pathType: Prefix
+        backend:
+          service:
+            name: foo-service
+            port:
+              number: 5678
+      - path: /bar
+        pathType: Prefix
+        backend:
+          service:
+            name: bar-service
+            port:
+              number: 5678
\ No newline at end of file

e36/README.org

+* Exercise 36 - Pod placement
+  - Time :: 10 minutes
+    - 4 minutes: /Try by yourself/
+    - 6 minutes: /Check, Verify, Ask/
+  - Description :: Modify the lb-example Deployment adding a
+    NodeSelector requiring a label =region=EDGE= constraint and deploy
+    it on a specific node.
+
+    If this does not work out of the box, try
+    to inspect why the scheduler is not able to complete the request
+    and apply corrective actions.
+
+* Solutions and Instructions
+** Inspect the modified Deployment
+   Identify the changes in [[file:lb-example-edge.yaml][this]] file
+** Deploy the new lb-example
+   #+BEGIN_SRC sh
+   kubectl create -f lb-example-edge.yaml
+   #+END_SRC
+** Check the work load
+   #+BEGIN_SRC sh
+   kubectl get pod -o wide
+   #+END_SRC
+** Check the scheduling status
+   #+BEGIN_SRC sh
+   kubectl describe pod -l app=lb-example-edge
+   #+END_SRC
+** Apply corrective actions
+   Open another terminal and watch the cluster status
+   #+BEGIN_SRC sh
+   kubectl get pod -o wide -w
+   #+END_SRC
+   Mark a node with a label =region=EDGE= and look at the other terminal
+   #+BEGIN_SRC sh
+   kubectl label node $USER-worker region=EDGE
+   #+END_SRC
+
+   Why k8s reacted instantly?

e36/lb-example-edge.yaml

+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: lb-example-edge
+  namespace: default
+  labels:
+    app: lb-example-edge
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: lb-example-edge
+  template:
+    metadata:
+      labels:
+        app: lb-example-edge
+    spec:
+      nodeSelector:
+        region: "EDGE"
+      containers:
+      - name: worker
+        image: python:3.6-alpine
+        command:
+        - "/bin/sh"
+        - "-ecx"
+        - |
+          echo "I am pod: $MY_POD_NAME runing on node: $MY_NODE_NAME" | tee index.html
+          python -m http.server 8000 2>&1
+        env:
+        - name: MY_NODE_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: spec.nodeName
+        - name: MY_POD_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: "lb-example-edge"
+  annotations:
+    # Create endpoints also if the related pod isn't ready
+    service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
+spec:
+  type: NodePort
+  ports:
+  - port: 8000
+    nodePort: 30001
+    targetPort: 8000
+  selector:
+    app: lb-example-edge