All technological notes.
Create a Persistent Volume with the given specification: -
Volume name: pv-analytics Storage: 100Mi Access mode: ReadWriteMany Host path: /pv/data-analytics
# pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv-analytics
spec:
capacity:
storage: 100Mi
accessModes:
- ReadWriteMany
hostPath:
path: "/pv/data-analytics"
k apply -f pv.yaml
# persistentvolume/pv-analytics created
# confirm
k get pv
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# pv-analytics 100Mi RWX Retain Available <unset> 11s
# confirm
k describe pv
# Name: pv-analytics
# Labels: <none>
# Annotations: <none>
# Finalizers: [kubernetes.io/pv-protection]
# StorageClass:
# Status: Available
# Claim:
# Reclaim Policy: Retain
# Access Modes: RWX
# VolumeMode: Filesystem
# Capacity: 100Mi
# Node Affinity: <none>
# Message:
# Source:
# Type: HostPath (bare host directory volume)
# Path: /pv/data-analytics
# HostPathType:
# Events: <none>
Create a PV name rompv with the accessmode ReadOnlyMany and a capacity of 1Gi.
# task-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: rompv
spec:
capacity:
storage: 1Gi
accessModes:
- ReadOnlyMany
hostPath:
path: "/mnt/data"
k apply -f task-pv.yaml
# persistentvolume/rompv created
# confirm
k get pv rompv
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# rompv 1Gi ROX Retain Available <unset> 42s
if pv type is not specified, use hostPath
A user accidentally deleted the MariaDB Deployment in the mariadb namespace, which was configured with persistent storage. Your responsibility is to re-establish the Deployment while ensuring data is preserved by reusing the available PersistentVolume.
Task: A PersistentVolume already exists and is retained for reuse. only one pv exist.
Create a PersistentVolumeClaim (PVC) named mariadb in the mariadb NS with the spec: Access mode ReadWriteOnce and Storage 250Mi
Edit the MariaDB Deploy file located at ~/mariadb-deploy.yaml to use PVC created in the previous step.
Apply the updated Deployment file to the cluster.
Ensure the MariaDB Deployment is running and Stable
ssh node02
sudo mkdir -p /mnt/data/mariadb
sudo chmod 777 /mnt/data/mariadb
ssh controlplane
kubectl create namespace mariadb
# create pv
tee pv.yaml<<'EOF'
apiVersion: v1
kind: PersistentVolume
metadata:
name: mariadb-pv
spec:
capacity:
storage: 250Mi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: local-path
hostPath:
path: /mnt/data/mariadb
EOF
kubectl apply -f pv.yaml
kubectl get pv mariadb-pv
# Create the MariaDB deploy YAML file
tee ~/mariadb-deploy.yaml<<'EOF'
apiVersion: apps/v1
kind: Deployment
metadata:
name: mariadb
namespace: mariadb
spec:
replicas: 1
selector:
matchLabels:
app: mariadb
template:
metadata:
labels:
app: mariadb
spec:
containers:
- name: mariadb
image: mariadb:11.4
ports:
- containerPort: 3306
env:
- name: MARIADB_ROOT_PASSWORD
value: "rootpass"
volumeMounts:
- name: data
mountPath: /var/lib/mysql
volumes:
- name: data
emptyDir: {}
EOF
kubectl apply -f ~/mariadb-deploy.yaml
# “accidentally deleted”
kubectl -n mariadb delete deployment mariadb --ignore-not-found
kubectl -n mariadb delete pvc mariadb --ignore-not-found
# Confirm
kubectl -n mariadb get deploy,pods,pvc
kubectl get pv
ls -l ~/mariadb-deploy.yaml
# get pv storageClass
kubectl get pv
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# mariadb-pv 250Mi RWO Retain Available local-path <unset> 6s
# pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mariadb
namespace: mariadb
spec:
storageClassName: local-path # match the pv sc
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 250Mi
kubectl apply -f pvc.yaml
# persistentvolumeclaim/mariadb created
# confirm
kubectl get pvc mariadb -n mariadb
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# mariadb Bound mariadb-pv 250Mi RWO local-path <unset> 6s
vi mariadb-deploy.yaml
# volumes:
# - name: data
# persistentVolumeClaim:
# claimName: mariadb
kubectl apply -f mariadb-deploy.yaml
# deployment.apps/mariadb created
kubectl get pod -n mariadb
# NAME READY STATUS RESTARTS AGE
# mariadb-586c877688-f5bbd 1/1 Running 0 77s
kubectl describe pod mariadb-586c877688-f5bbd -n mariadb
# Containers:
# mariadb:
# Mounts:
# /var/lib/mysql from data (rw)
# Volumes:
# data:
# Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
# ClaimName: mariadb
设置配置环境： [candidate@node-1] $ kubectl config use-context hk8s
Task 创建名为 app-config 的 persistent volume，容量为 1Gi，访问模式为 ReadWriteMany。 volume 类型为 hostPath，位于 /srv/app-config
# pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: app-config
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteMany
hostPath:
path: "/srv/app-config"
kubectl apply -f pv.yaml
# persistentvolume/app-config created
kubectl get pv app-config
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# app-config 1Gi RWX Retain Available <unset> 27s
kubectl describe pv app-config
# Name: app-config
# Labels: <none>
# Annotations: <none>
# Finalizers: [kubernetes.io/pv-protection]
# StorageClass:
# Status: Available
# Claim:
# Reclaim Policy: Retain
# Access Modes: RWX
# VolumeMode: Filesystem
# Capacity: 1Gi
# Node Affinity: <none>
# Message:
# Source:
# Type: HostPath (bare host directory volume)
# Path: /srv/app-configCopy
# HostPathType:
# Events: <none>
A developer needs a persistent volume for an application. Create a PersistentVolumeClaim with: · size 100Mi . access mode ReadWriteOnce . using the storage class “local-path” (installed)
Create a Pod that mounts this PVC at /data and verify that the volume is automatically created and mounted.
Solution
ref:
# pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: task-pvc
spec:
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 100Mi
storageClassName: csi-hostpath-sc
kubectl apply -f pvc.yaml
# persistentvolumeclaim/task-pvc created
# confirm
kubectl get pvc task-pvc
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# task-pvc Bound pvc-92755743-039e-488b-86c0-d0a46a2ebdda 100Mi RWO csi-hostpath-sc <unset> 6m30s
# pvc-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: task-pvc-pod
spec:
volumes:
- name: task-pvc-vol
persistentVolumeClaim:
claimName: task-pvc
containers:
- name: busybox
image: busybox
volumeMounts:
- mountPath: "/data"
name: task-pvc-vol
command:
- "sh"
- "-c"
args:
- |
echo "task pvc" >> /data/msg.txt;
sleep infinity
kubectl apply -f pvc-pod.yaml
# pod/task-pvc-pod created
kubectl get pod task-pvc-pod
# NAME READY STATUS RESTARTS AGE
# task-pvc-pod 1/1 Running 0 36s
kubectl describe pod task-pvc-pod
# Volumes:
# task-pvc-vol:
# Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
# ClaimName: task-pvc
# ReadOnly: false
设置配置环境： [candidate@node-1] $ kubectl config use-context ok8s
Task 创建一个新的 PersistentVolumeClaim： 名称: pv-volume Class: csi-hostpath-sc 容量: 10Mi
创建一个新的 Pod，来将 PersistentVolumeClaim 作为 volume 进行挂载： 名称：web-server Image：nginx:1.16 挂载路径：/usr/share/nginx/html
配置新的 Pod，以对 volume 具有 ReadWriteOnce 权限。
最后，使用 kubectl edit 或 kubectl patch 将 PersistentVolumeClaim 的容量扩展为 70Mi，并记录此更改。
# pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: pv-volume
spec:
storageClassName: csi-hostpath-sc
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 10Mi
kubectl apply -f pvc.yaml
# persistentvolumeclaim/pv-volume created
kubectl get pvc
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# pv-volume Bound pvc-20bb7ba7-c811-47c6-85fb-13881c9af538 10Mi RWO csi-hostpath-sc <unset> 4m
# pvc-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: web-server
spec:
volumes:
- name: pv-storage
persistentVolumeClaim:
claimName: pv-volume
containers:
- name: nginx
image: nginx:1.16
volumeMounts:
- mountPath: "/usr/share/nginx/html"
name: pv-storage
kubectl apply -f pvc-pod.yaml
# pod/web-server created
kubectl get pod web-server
# NAME READY STATUS RESTARTS AGE
# web-server 1/1 Running 0 24s
kubectl describe pod web-server
# Containers:
# nginx:
# Mounts:
# /usr/share/nginx/html from pv-storage (rw)
# Volumes:
# pv-storage:
# Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
# ClaimName: pv-volume
kubectl edit pvc pv-volume --record
# spec:
# resources:
# requests:
# storage: 70Mi
# persistentvolumeclaim/pv-volume edited
# confirm
kubectl get pvc pv-volume
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# pv-volume Bound pvc-20bb7ba7-c811-47c6-85fb-13881c9af538 70Mi RWO csi-hostpath-sc <unset> 12m
kubectl describe pvc pv-volume
# Capacity: 70Mi
# Events:
# Type Reason Age From Message
# ---- ------ ---- ---- -------
# Normal Resizing 26s external-resizer hostpath.csi.k8s.io External resizer is resizing volume pvc-20bb7ba7-c811-47c6-85fb-13881c9af538
# Normal FileSystemResizeRequired 25s external-resizer hostpath.csi.k8s.io Require file system resize of volume on node
Manage persistent volumes and persistent volume claims
Task :
# task-pvc02.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: rwopvc
spec:
accessModes:
- ReadWriteOnce
volumeMode: Filesystem
resources:
requests:
storage: 400Mi
---
apiVersion: v1
kind: Pod
metadata:
name: rwopod
spec:
containers:
- name: nginx
image: nginx
volumeMounts:
- mountPath: "/var/www/html"
name: mypd
volumes:
- name: mypd
persistentVolumeClaim:
claimName: rwopvc
kubectl apply -f task-pvc02.yaml
k get pvc rwopvc
k describe pod rwopod
# Containers:
# nginx:
# Mounts:
# /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-cvmsd (ro)
# /var/www/html from mypd (rw)
# Volumes:
# mypd:
# Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
# ClaimName: rwopvc
# ReadOnly: false
Manually create a PersistentVolume that: · is named static-pv-example . requests 200Mi . uses a hostPath on node01 . access mode ReadWriteOnce . Retain reclaim policy
Then create a matching PersistentVolumeClaim (static-pvc-example) to bind to it
# task-03-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: static-pv-example
spec:
capacity:
storage: 200Mi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
hostPath:
path: /mnt/static-pv
type: DirectoryOrCreate
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- node01
kubectl apply -f task-03-pv.yaml
# persistentvolume/static-pv-example created
k get pv static-pv-example
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# static-pv-example 200Mi RWO Retain Bound default/static-pvc-example <unset> 46s
# task-03-pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: static-pvc-example
spec:
storageClassName: "" # specify bind with the static pv
volumeName: static-pv-example
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 200Mi
kubectl apply -f task-03-pvc.yaml
# persistentvolumeclaim/static-pvc-example created
kubectl get pvc static-pvc-example
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# static-pvc-example Bound static-pv-example 200Mi RWO <unset> 80s
A PersistentVolumeClaim named app-pvc exists in the namespace storage-ns, but it is not getting bound to the available PersistentVolume named app-pv.
Inspect both the PVC and PV and identify why the PVC is not being bound and fix the issue so that the PVC successfully binds to the PV. Do not modify the PV resource.
k create ns storage-ns
tee pv.yaml<<EOF
apiVersion: v1
kind: PersistentVolume
metadata:
name: app-pv
spec:
capacity:
storage: 1Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
EOF
tee pvc.yaml<<EOF
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: app-pvc
namespace: storage-ns
spec:
storageClassName: ""
accessModes:
- ReadWriteMany
resources:
requests:
storage: 1Gi
EOF
k apply -f pv.yaml
k apply -f pvc.yaml
k get pv
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# app-pv 1Gi RWO Retain Available <unset> 21s
k get pvc -n storage-ns
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# app-pvc Pending local-path <unset> 43s
# debug
k describe pv
# Name: app-pv
# Labels: <none>
# Annotations: <none>
# Finalizers: [kubernetes.io/pv-protection]
# StorageClass:
# Status: Available
# Claim:
# Reclaim Policy: Retain
# Access Modes: RWO
# VolumeMode: Filesystem
# Capacity: 1Gi
# Node Affinity: <none>
# Message:
# Source:
# Type: HostPath (bare host directory volume)
# Path: /mnt/data
# HostPathType:
# Events: <none>
k get pvc app-pvc -n storage-ns -o yaml
# apiVersion: v1
# kind: PersistentVolumeClaim
# metadata:
# annotations:
# kubectl.kubernetes.io/last-applied-configuration: |
# {"apiVersion":"v1","kind":"PersistentVolumeClaim","metadata":{"annotations":{},"name":"app-pvc","namespace":"storage-ns"},"spec":{"accessModes":["ReadWriteMany"],"resources":{"requests":{"storage":"1Gi"}}}}
# creationTimestamp: "2026-01-21T19:55:57Z"
# finalizers:
# - kubernetes.io/pvc-protection
# name: app-pvc
# namespace: storage-ns
# resourceVersion: "34861"
# uid: 40242e27-4d47-49a9-a106-f1d750c0f8f3
# spec:
# accessModes:
# - ReadWriteMany <============== not match
# resources:
# requests:
# storage: 1Gi
# storageClassName: local-path
# volumeMode: Filesystem
# status:
# phase: Pending
# fix
k edit pvc app-pvc -n storage-ns
# spec:
# accessModes:
# - ReadWriteOnce
# confirm
get pvc -n storage-ns
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# app-pvc Bound app-pv 1Gi RWO <unset> 10s
Create a StorageClass named local-sc with the following specifications and set it as the default storage class:
The provisioner should be kubernetes.io/no-provisioner The volume binding mode should be WaitForFirstConsumer Volume expansion should be enabled
# sc.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: local-sc
annotations:
storageclass.kubernetes.io/is-default-class: "true"
provisioner: kubernetes.io/no-provisioner
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
kubectl apply -f sc.yaml
kubectl get sc
Create a StorageClass: . named fast-storage . uses the rancher.io/local-path provisioner sets a Retain reclaim policy . uses Immediate binding (default)
Create a PersistentVolume and a PersistentVolumeClaim: . the PV should use fast-storage · configure node affinity so Kubernetes knows where to create the volume (node01) . the PVC should bind to that PV . Verify that when the PVC is deleted, the PV remains (in Released state)
# storageClass.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: fast-storage
provisioner: rancher.io/local-path
reclaimPolicy: Retain
volumeBindingMode: Immediate
kubectl apply -f storageClass.yaml
# storageclass.storage.k8s.io/fast-storage created
kubectl get sc fast-storage
# NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
# fast-storage rancher.io/local-path Retain Immediate false 12s
# task-sc-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: fast-storage-pv
spec:
capacity:
storage: 100Mi
accessModes:
- ReadWriteOnce
storageClassName: fast-storage
persistentVolumeReclaimPolicy: Retain
hostPath:
path: /mnt/fast-storage/pv
type: DirectoryOrCreate
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- node01
kubectl apply -f task-sc-pv.yaml
# persistentvolume/fast-storage-pv created
kubectl get pv fast-storage-pv
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# fast-storage-pv 100Mi RWO Retain Available fast-storage <unset> 55s
# task-sc-pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: fast-storage-pvc
spec:
accessModes:
- ReadWriteOnce
storageClassName: fast-storage
volumeName: fast-storage-pv
resources:
requests:
storage: 100Mi
kubectl apply -f task-sc-pvc.yaml
# persistentvolumeclaim/fast-storage-pvc created
kubectl get pvc fast-storage-pvc
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# fast-storage-pvc Bound fast-storage-pv 100Mi RWO fast-storage <unset> 11s
Create a new StorageClass named low-latency that uses the existing provisioner rancher.io/local-path. Set the VolumeBindingMode to WaitForFirstConsumer. (Mandatory or the score will be reduced)
Make the newly created StorageClass (low-latency) the default StorageClass in the cluster.
Do NOT modify any existing Deployments or PersistentVolumeClaims. (If modified, the-score will be reduced)
# sc.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: low-latency
annotations:
storageclass.kubernetes.io/is-default-class: "true"
provisioner: rancher.io/local-path
volumeBindingMode: WaitForFirstConsumer
kubectl apply -f sc.yaml
# storageclass.storage.k8s.io/low-latency created
# Mark the default StorageClass as non-default
kubectl patch sc local-path -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'
# storageclass.storage.k8s.io/local-path patched
kubectl get sc
# NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE
# local-path rancher.io/local-path Delete WaitForFirstConsumer false 2d22h
# low-latency (default) rancher.io/local-path Delete WaitForFirstConsumer false 5s
Create a StorageClass named rancher-sc with the following specifications:
The provisioner should be rancher.io/local-path. The volume binding mode should be WaitForFirstConsumer. Volume expansion should be enabled.
tee sc.yaml<<EOF
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: rancher-sc
provisioner: rancher.io/local-path
volumeBindingMode: WaitForFirstConsumer
allowVolumeExpansion: true
EOF
kubectl apply -f sc.yaml
# storageclass.storage.k8s.io/rancher-sc created
pv: web-pv; rwo, 100mi, hostpath /vol/data pvc: web-pvc, ns=production, use pv, deploy: web-deploy, ns=production, nginx:1.14.2, use pvc, /tmp/web-data
list all pv sorted by capacity, saving the full kubectl output to /op/pv/pv_list.txt
kubectl get pv --sort-by=.spec.capacity.storage
# NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS VOLUMEATTRIBUTESCLASS REASON AGE
# web-pv 2Gi RWO Retain Bound production/web-pvc <unset> 114m
kubectl get pv --sort-by=.spec.capacity.storage > /op/pv/pv_list.txt
# Reversely
kubectl get pv --sort-by=.spec.capacity.storage | tac
k get pvc --sort-by=.spec.resources.requests.storage
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE
# pv-volume Bound pvc-07c491d2-dbf2-4095-99e2-ec935381b79b 10Mi RWO local-path <unset> 63m
# q01-pvc Bound pvc-2fb142b8-7ae4-442a-a338-999a924fd2a3 100Mi RWO local-path <unset> 67m
# static-pvc-example Bound static-pv-example 200Mi RWO <unset> 43m
# rwopvc Bound pvc-43f71f51-9499-4e4c-8f84-80d90eb18702 400Mi RWO local-path <unset> 58m
k get pvc --sort-by=.spec.resources.requests.storage | tac
# rwopvc Bound pvc-43f71f51-9499-4e4c-8f84-80d90eb18702 400Mi RWO local-path <unset> 58m
# static-pvc-example Bound static-pv-example 200Mi RWO <unset> 43m
# q01-pvc Bound pvc-2fb142b8-7ae4-442a-a338-999a924fd2a3 100Mi RWO local-path <unset> 67m
# pv-volume Bound pvc-07c491d2-dbf2-4095-99e2-ec935381b79b 10Mi RWO local-path <unset> 63m
# NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE