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This article shows you how to use emptyDir,hostPath,nfs,pv,pvc to do storage in K8s. The content is concise and easy to understand, which will definitely brighten your eyes. I hope you can get something through the detailed introduction of this article.

There are three ways to store volumes: emptyDir,gitRepo,hostPath

EmptyDir: a pod creates two containers, one pod provides request service, the other pod provides file storage, pod deletes, and the storage volume is deleted.

GitRepo: provides storage using docker mirrors

HostPath: host path, pod deleted, storage volume still there (path to be created in multiple node nodes)

Nfs: using shared storage (multiple pod to create multiple directories in shared storage)

Help:

[root@k8s1 ~] # kubectl explain pods.spec.volumes.persistentVolumeClaim-- pvc help

[root@k8s1 ~] # kubectl explain pods.spec.volumes-- View help

[root@k8s1 ~] # kubectl explain pv-- pv help

1. Use emptyDir for storage (two pod, one for storage and one for service)

[root@k8s1 ~] # vim 11.yaml

ApiVersion: v1

Kind: Pod

Metadata:

Name: pod-demo-- define a pod

Namespace: default

Labels:

App: myapp

Tier: frontend

Spec:

Containers:

-name: myapp-- define a container

Image: ikubernetes/myapp:v1

ImagePullPolicy: IfNotPresent

Ports:

-name: http

ContainerPort: 80

VolumeMounts:

-name: html

MountPath: / usr/share/nginx/html-- the myapp container html volume is mounted to / usr/share/nginx/html (is the default path for nginx)

-name: busybox

Image: busybox:latest

ImagePullPolicy: IfNotPresent

VolumeMounts:

-name: html-- the busybox container mounts the html volume to / data

MountPath: / data/

Command: ["/ bin/sh", "- c", "while true;do echo $(date) > > / data/index.html;sleep 2done"]

Volumes:-- define a html volume

-name: html

EmptyDir: {}

[root@k8s1] # kubectl apply-f 11.yaml

Pod/pod-demo created

[root@k8s1] # kubectl get pods-o wide

NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES

Pod-demo 2/2 Running 0 103s 10.244.1.13 k8s2

[root@k8s1] # kubectl exec-it pod-demo-c busybox-/ bin/sh

/ # cat / data/index.html

Fri Feb 22 09:39:53 UTC 2019

Fri Feb 22 09:39:55 UTC 2019

Fri Feb 22 09:39:57 UTC 2019

Fri Feb 22 09:39:59 UTC 2019

[root@k8s1 ~] # curl http://10.244.1.13

Fri Feb 22 09:39:53 UTC 2019

Fri Feb 22 09:39:55 UTC 2019

Fri Feb 22 09:39:57 UTC 2019

Fri Feb 22 09:39:59 UTC 2019

Fri Feb 22 09:40:01 UTC 2019

Fri Feb 22 09:40:03 UTC 2019

Fri Feb 22 09:40:05 UTC 2019

[root@k8s1 ~] #

two。 Use hostPath for storage (if the node node is down, the data of pod accessing the down node will not exist)

Node1 node:

[root@k8s2] # mkdir-p / data/pod

[root@k8s2 ~] # cat / data/pod/index.html-to distinguish between node nodes, write the contents of the file differently

Node1

[root@k8s2 ~] #

Node2 node:

[root@k8s3] # mkdir-p / data/pod

[root@k8s3 ~] # cat / data/pod/index.html

Node2

[root@k8s3 ~] #

Master node:

[root@k8s1 ~] # vim 12.yaml

ApiVersion: v1

Kind: Pod

Metadata:

Name: pod-vol-hostpath

Namespace: default

Spec:

Containers:

-name: myapp

Image: ikubernetes/myapp:v1

VolumeMounts:

-name: html-- using html volume storage

MountPath: / usr/share/nginx/html-- nginx web page root directory

Volumes:

-name: html

HostPath:

Path: / data/pod/-- the path of the html volume (create a new directory for the corresponding node node, and create a new node for pod)

Type: DirectoryOrCreate

[root@k8s1] # kubectl get pods-o wide

NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES

Pod-demo 2/2 Running 0 64m 10.244.1.13 k8s2

Pod-vol-hostpath 1/1 Running 0 4s 10.244.2.22 k8s3

[root@k8s1 ~] # curl http://10.244.2.22-- pod is on the node2 node, so you are visiting the web page of node2. If you are in node1, it is the content of node1.

Node2

[root@k8s1 ~] #

3. Using nfs shared Storage

Nfs storage:

[root@liutie1 ~] # mkdir / data/v6

[root@liutie1 ~] # vim / etc/exports

/ data/v6 172.16.8.0 Compact 24 (rw,no_root_squash)

[root@liutie1 ~] # systemctl restart nfs

[root@liutie1 ~] # exportfs-arv

Exporting 172.16.8.0/24:/data/v6

[root@liutie1] # showmount-e

Export list for liutie1:

/ data/v6 172.16.8.0/24

[root@liutie1 ~] #

K8s node:

[root@k8s1 ~] # mkdir / data/v6-create a shared directory

[root@k8s1 ~] # mount.nfs 172.16.8.108:/data/v6 / data/v6-- Test manual mount

[root@k8s1 ~] # umount / data/v6

[root@k8s1 ~] # vim nfs.yaml

ApiVersion: v1

Kind: Pod

Metadata:

Name: pod-vol-nfs

Namespace: default

Spec:

Containers:

-name: pod-nfs

Image: ikubernetes/myapp:v1

VolumeMounts:

-name: html1

MountPath: / usr/share/nginx/html

Volumes:

-name: html1

Nfs:

Path: / data/v6

Server: 172.16.8.108

[root@k8s1] # kubectl apply-f nfs.yaml

Pod/pod-vol-nfs created

[root@k8s1] # kubectl get pods-o wide

NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES

Pod-vol-nfs 1/1 Running 0 2m21s 10.244.1.78 k8s2

[root@k8s1 ~] #

Create a file in the nfs store

[root@liutie1 ~] # cd / data/v6/

[root@liutie1 v6] # cat index.html

Nfs store

[root@liutie1 v6] #

Open the web page in the k8s node

[root@k8s1 ~] # curl 10.244.1.78-ip address of pod

Nfs store

[root@k8s1 ~] #

4. Use nfs shared storage (fixed size)

Nfs server:

[root@liutie1 ~] # mkdir / data/v {1pm 2je 3pm 4pm 5}-- create a new directory on the storage

[root@liutie1 ~] # yum install nfs*-y-install nfs

[root@liutie1 ~] # vim / etc/exports-- shared directory

/ data/v1 172.16.8.0 Compact 24 (rw,no_root_squash)

/ data/v2 172.16.8.0 Compact 24 (rw,no_root_squash)

/ data/v3 172.16.8.0 Compact 24 (rw,no_root_squash)

/ data/v4 172.16.8.0 Compact 24 (rw,no_root_squash)

/ data/v5 172.16.8.0 Compact 24 (rw,no_root_squash)

[root@liutie1 ~] # exportfs-arv

Exporting 172.16.8.0/24:/data/v5

Exporting 172.16.8.0/24:/data/v4

Exporting 172.16.8.0/24:/data/v3

Exporting 172.16.8.0/24:/data/v2

Exporting 172.16.8.0/24:/data/v1

[root@liutie1] # showmount-e

Export list for liutie1:

/ data/v5 172.16.8.0/24

/ data/v4 172.16.8.0/24

/ data/v3 172.16.8.0/24

/ data/v2 172.16.8.0/24

/ data/v1 172.16.8.0/24

[root@liutie1 ~] #

Node nodes:

[root@k8s2 ~] # yum install nfs-common nfs-utils-y-all node nodes must have nfs-utils packages installed, otherwise errors will occur

Master node:

[root@k8s1 ~] # yum install-y nfs-utils

[root@k8s1 ~] # kubectl explain PersistentVolume-help information

[root@k8s1 ~] # vim pv.yaml-- convert remote nfs directories to pv

ApiVersion: v1

Kind: PersistentVolume

Metadata:

Name: pv001

Labels:

Name: pv001

Spec:

Nfs:

Path: / data/v1

Server: 172.16.8.108

AccessModes: ["ReadWriteMany", "ReadWriteOnce"]

Capacity:

Storage: 5Gi

-

ApiVersion: v1

Kind: PersistentVolume

Metadata:

Name: pv002

Labels:

Name: pv002

Spec:

Nfs:

Path: / data/v2

Server: 172.16.8.108

AccessModes: ["ReadWriteMany", "ReadWriteOnce"]

Capacity:

Storage: 15Gi

-

ApiVersion: v1

Kind: PersistentVolume

Metadata:

Name: pv003

Labels:

Name: pv003

Spec:

Nfs:

Path: / data/v3

Server: 172.16.8.108

AccessModes: ["ReadWriteMany", "ReadWriteOnce"]

Capacity:

Storage: 1Gi

-

ApiVersion: v1

Kind: PersistentVolume

Metadata:

Name: pv004

Labels:

Name: pv004

Spec:

Nfs:

Path: / data/v4

Server: 172.16.8.108

AccessModes: ["ReadWriteMany", "ReadWriteOnce"]

Capacity:

Storage: 20Gi

-

ApiVersion: v1

Kind: PersistentVolume

Metadata:

Name: pv005

Labels:

Name: pv005

Spec:

Nfs:

Path: / data/v5

Server: 172.16.8.108

AccessModes: ["ReadWriteMany", "ReadWriteOnce"]

Capacity:

Storage: 13Gi

[root@k8s1 ~] # kubectl apply-f pv.yaml-generate pv

Persistentvolume/pv001 created

Persistentvolume/pv002 created

Persistentvolume/pv003 created

Persistentvolume/pv004 created

Persistentvolume/pv005 created

[root@k8s1 ~] # kubectl get pv-- View pv

NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE

Pv001 5Gi RWO,RWX Retain Available 2m40s

Pv002 15Gi RWO,RWX Retain Available 2m40s

Pv003 1Gi RWO,RWX Retain Available 2m40s

Pv004 20Gi RWO,RWX Retain Available 2m40s

Pv005 13Gi RWO,RWX Retain Available 2m40s

[root@k8s1 ~] # vim pvc.yaml-create a pvc,pvc with a size of 6G

ApiVersion: v1

Kind: PersistentVolumeClaim

Metadata:

Name: mypvc

Namespace: default-- pvc that defines a mypvc name

Spec:

AccessModes: ["ReadWriteMany"]

Resources:

Requests:

Storage: 6Gi

-

ApiVersion: v1

Kind: Pod-- defines a pod,pod that uses pvc

Metadata:

Name: pod-vol-pvc

Namespace: default

Spec:

Containers:

-name: myapp

Image: ikubernetes/myapp:v1

VolumeMounts:

-name: html-- using mypvc storage

MountPath: / usr/share/nginx/html

Volumes:

-name: html

PersistentVolumeClaim:

ClaimName: mypvc-- reference the mypvc above

[root@k8s1] # kubectl apply-f pvc.yaml

Persistentvolumeclaim/mypvc created

Pod/pod-vol-pvc created

[root@k8s1 ~] # kubectl get pv

NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE

Pv001 5Gi RWO,RWX Retain Available 8m31s

Pv002 15Gi RWO,RWX Retain Available 8m31s

Pv003 1Gi RWO,RWX Retain Available 8m31s

Pv004 20Gi RWO,RWX Retain Available 8m31s

Pv005 13Gi RWO,RWX Retain Bound default/mypvc 8m31s-- Bound means to use the

[root@k8s1 ~] # kubectl get pvc

NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE

Mypvc Bound pv005 13Gi RWO,RWX 2m31s-mypvc storage volume using pv005

[root@k8s1 ~] # kubectl get pods

NAME READY STATUS RESTARTS AGE

Pod-demo 2/2 Running 0 141m

Pod-vol-hostpath 1/1 Running 0 77m

Pod-vol-pvc 1/1 Running 0 4s

[root@k8s1 ~] # kubectl describe pods pod-vol-pvc-- View details

The above is how to use emptyDir,hostPath,nfs,pv,pvc for storage in K8s. Have you learned any knowledge or skills? If you want to learn more skills or enrich your knowledge reserve, you are welcome to follow the industry information channel.

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