DevOps Classroom notes 17/Oct/2026

Hostpath Volume:

• A hostpth volume in k8s mount as filesystem or directory.
• it will create same node where my pod will deploy.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: recreate-deployment-app
  labels:
    app: apache2
spec:
  replicas: 2
  selector:
    matchLabels:
      app: apache2
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: apache2
    spec:
      initContainers:
        - name: download-template
          image: alpine:latest
          command:
            - sh
            - -c
            - |
              set -e
              apk add --no-cache wget unzip
              wget -O /tmp/template.zip \
                https://templatemo.com/tm-zip-files-2020/templatemo_589_lugx_gaming.zip
              mkdir -p /tmp/template
              unzip -o /tmp/template.zip -d /tmp/template
              cp -a /tmp/template/templatemo_589_lugx_gaming/. \
                /usr/local/apache2/htdocs/
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/

      containers:
        - name: apache2
          image: httpd:2
          ports:
            - containerPort: 80
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/

      volumes:
        - name: apache2-html
          hostPath:
            path: /var/data/apache2-htdocs
            type: DirectoryOrCreate

Configmap & Secrets mount volume:

1. create configMap

apiVersion: v1
Kind: ConfigMap
metadata:
  name: app-config
data:
  location: hyd
  app.properties: |
    mode=production
    log_level=info

Add configmap volume mount pah

apiVersion: apps/v1
kind: Deployment
metadata:
  name: recreate-deployment-app
  labels:
    app: apache2
spec:
  replicas: 2
  selector:
    matchLabels:
      app: apache2
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: apache2
    spec:
      initContainers:
        - name: download-template
          image: alpine:latest
          command:
            - sh
            - -c
            - |
              set -e
              apk add --no-cache wget unzip
              wget -O /tmp/template.zip \
                https://templatemo.com/tm-zip-files-2020/templatemo_589_lugx_gaming.zip
              mkdir -p /tmp/template
              unzip -o /tmp/template.zip -d /tmp/template
              cp -a /tmp/template/templatemo_589_lugx_gaming/. \
                /usr/local/apache2/htdocs/
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/
      containers:
        - name: apache2
          image: httpd:2
          ports:
            - containerPort: 80
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/
            - name: app-config-data
              mountPath: /etc/app
      volumes:
        - name: apache2-html
          hostPath:
            path: /var/data/apache2-htdocs
            type: DirectoryOrCreate
        - name: app-config-data
          configMap:
            name: app-config

2. secret mount

kubectl create secret generic rds-secret \
  --from-literal=DB_HOST=://amazonaws.com \
  --from-literal=DB_PORT=5432 \
  --from-literal=DB_USER=dbadmin \
  --from-literal=DB_PASSWORD=yoursecurepassword

Generate yaml by using --dry-run=client -o yaml

To create secret by yaml

apiVersion: v1
data:
  DB_HOST: Oi8vYW1hem9uYXdzLmNvbQ==
  DB_PASSWORD: eW91cnNlY3VyZXBhc3N3b3Jk
  DB_PORT: NTQzMg==
  DB_USER: ZGJhZG1pbg==
kind: Secret
metadata:
  name: rds-secret

apiVersion: apps/v1
kind: Deployment
metadata:
  name: recreate-deployment-app
  labels:
    app: apache2
spec:
  replicas: 2
  selector:
    matchLabels:
      app: apache2
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: apache2
    spec:
      initContainers:
        - name: download-template
          image: alpine:latest
          command:
            - sh
            - -c
            - |
              set -e
              apk add --no-cache wget unzip
              wget -O /tmp/template.zip \
                https://templatemo.com/tm-zip-files-2020/templatemo_589_lugx_gaming.zip
              mkdir -p /tmp/template
              unzip -o /tmp/template.zip -d /tmp/template
              cp -a /tmp/template/templatemo_589_lugx_gaming/. \
                /usr/local/apache2/htdocs/
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/
      containers:
        - name: apache2
          image: httpd:2
          ports:
            - containerPort: 80
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/
            - name: app-config-data
              mountPath: /etc/app
            - name: rds-secret-pg
              mountPath: /etc/secrets
              readOnly: true
      volumes:
        - name: apache2-html
          hostPath:
            path: /var/data/apache2-htdocs
            type: DirectoryOrCreate
        - name: app-config-data
          configMap:
            name: app-config
        - name: rds-secret-pg
          secret:
            secretName: rds-secret

Presistance volume:

Offical docs

• k8s pv will suppourt multiple back storages

Offical docs for PV API referance

accessModes in volume:

RWO ==> ReadWirteOnce (Read-wirte by a single node) – local storage RWM ==> ReadWirteMany (Read-wirte by many nodes) – NFS ROM ==> ReadOnlyMany (Read-only by many nodes) RWOP ==> ReadWirteOncePod (single pod having read-wirte once)

Actions required

sudo mkdir -p /mnt/data
sudo chmod 777 /mnt/data

Create PV, PVC and deployment

apiVersion: v1
kind: PersistentVolume
metadata:
  name: sample-pv
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: local-storage
  volumeMode: Filesystem
  local:
    path: /mnt/data
    fsType: ext4
  nodeAffinity:
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:
                - ip-172-31-39-231

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: sample-pvc
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: local-storage
  volumeName: sample-pv

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: recreate-deployment-app
  labels:
    app: apache2
spec:
  replicas: 2
  selector:
    matchLabels:
      app: apache2
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: apache2
    spec:
        
      initContainers:
        - name: download-template
          image: alpine:latest
          command:
            - sh
            - -c
            - |
              set -e

              apk add --no-cache wget unzip

              wget -O /tmp/template.zip \
                https://templatemo.com/tm-zip-files-2020/templatemo_589_lugx_gaming.zip

              mkdir -p /tmp/template

              unzip -o /tmp/template.zip -d /tmp/template

              cp -a /tmp/template/templatemo_589_lugx_gaming/. \
                /usr/local/apache2/htdocs/
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/

      containers:
        - name: apache2
          image: httpd:2
          ports:
            - containerPort: 80
          volumeMounts:
            - name: apache2-html
              mountPath: /usr/local/apache2/htdocs/

      volumes:
        - name: apache2-html
          persistentVolumeClaim:
            claimName: sample-pvc

Task:

1. create a pv name qt-pv

• capacity: 2GI
• VolumeType:local
• Hostpath: /qt/data
• Nodeaffinity: spcific node

2. create pvc

   1. request: 1Gi
   2. access: rwo
   3. bind pv volumeName: sample-pv

3. attach this volume to deployment:

   1. nginx
   2. replic2
   3. /usr/share/nginx/html -volume mount