Table of Contents |
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HostPath Volume
Simply add hostpath to volumes section in the deployment definition:
volumes:
- name: local-vol
hostPath:
path: {{ .Values.persistentVolume.path }}
type: DirectoryOrCreate
Example:
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kind: Deployment
...
spec:
containers:
- name: registry
...
volumeMounts:
- mountPath: /var/lib/registry
name: local-vol
subPath: registry/data
volumes:
- name: local-vol
hostPath:
path: {{ .Values.persistentVolume.path }}
type: DirectoryOrCreate
... |
HostPath Storage using Persistent Volume
This is the simplest and best approach for bare metal deployments when a network file system is not available.
Define storage class and make it the default
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apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: hostpath-storage
annotations:
storageclass.kubernetes.io/is-default-class: "true"
provisioner: keystone/hostpath-storage
volumeBindingMode: Immediate
reclaimPolicy: Retain |
Remove default status from other storage classes
> kubectl patch storageclass <STORAGE_CLASS> -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}'
Create Persistent Volumes
This example creates 10 persistent volumes using helm
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{{- $root := . -}}
{{range $i, $e := until 10}}
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv-{{ $i }}
spec:
capacity:
storage: {{ $root.Values.persistentVolume.size }}
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: hostpath-storage
hostPath:
path: /var/pv/pv-{{ $i }}
type: DirectoryOrCreate
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: NotIn
values:
- master
---
{{end}} |
Make a Claim using Default Storage Class
Code Block | ||
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kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: my-claim
spec:
storageClassName: ""
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 2Gi |
Local Storage using Persistent Volume and Claim
We can use disk space on a node by defining a PersistentVolume (see below) and then making a claim against that volume by specifying the storageclass name in the PersistentVolumeClaim.
- Only one claim can be made against a volume.
- File path (local.path) must exist for the volume to be usable.
- USE HOSTPATH STORAGE since it will create the folders for you.
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apiVersion: v1
kind: PersistentVolume
metadata:
name: local-storage
spec:
capacity:
storage: 10Gi
# volumeMode field requires BlockVolume Alpha feature gate to be enabled.
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Persist
storageClassName: local-storage
local:
path: /var/k8s/LOCAL_STORAGE
nodeAffinity:
required:
nodeSelectorTerms:
- matchExpressions:
- key: kubernetes.io/hostname
operator: In
values:
- k8sworker1
- k8sworker2
- k8sworker3
- docker-for-desktop
---
|
Make a claim by specifying the storage class
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kind: PersistentVolumeClaim apiVersion: v1 metadata: name: local-storage-claim spec: storageClassName: local-storage accessModes: - ReadWriteOnce resources: requests: storage: 3Gi |
Make any required folders on the worker nodes:
ssh k8sworker1
sudo mkdir -p /var/k8s/LOCAL_STORAGE
Repeat for all nodes requiring local storage.
Using Default Storage Class with Prebuilt Persistent Volumes
We can create a storage class for our local-storage class the default
...
storage and use it as default storage. The only issue with doing this with local-storage is that we need to pre-build all of the persistent volumes. Since only 1 claim can be made against a volume, we will need to make a few.
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apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: local-storage |
...
annotations: storageclass.kubernetes.io/is-default-class |
...
: " |
...
Make a claim using the default
Code Block |
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kind: PersistentVolumeClaimtrue" provisioner: keystone/local-storage volumeBindingMode: Immediate reclaimPolicy: Retain --- apiVersion: v1 kind: PersistentVolume metadata: name: local-storage-claim spec:1 spec: capacity: storage: 2Gi volumeMode: Filesystem accessModes: - ReadWriteOnce persistentVolumeReclaimPolicy: Retain storageClassName: "" accessModes: local-storage local: path: /var/pv1 nodeAffinity: required: nodeSelectorTerms: - ReadWriteOncematchExpressions: resources: - key: kubernetes.io/hostname requestsoperator: NotIn storage values: 3Gi |
Make a claim by specifying the storage class
- master
---
...REPEAT UNTIL HAPPY ... |
To use the default storage of the cluster, you just need to create a claim and specify "" for storageClassName.
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Code Block | ||
kind: PersistentVolumeClaim apiVersion: v1 metadata: name: local-storage-claim spec: storageClassName: local-storage"" accessModes: - ReadWriteOnce resources: requests: storage: 3Gi |
...
GlusterFS
sudo mkdir -p /var/k8s/LOCAL_STORAGE
Gluster-kubernetes is a project to provide Kubernetes administrators a mechanism to easily deploy GlusterFS as a native storage service onto an existing Kubernetes cluster.
See https://github.com/gluster/gluster-kubernetes
Repeat for all nodes requiring local storage.
From master node
...
References
Reference | URL |
---|---|
Volumes - Kubernetes | https://kubernetes.io/docs/concepts/storage/volumes/ |
Local Persistent Volumes for Kubernetes Goes Beta | https://kubernetes.io/blog/2018/04/13/local-persistent-volumes-beta/ |
Change Default Storage Class | https://kubernetes.io/docs/tasks/administer-cluster/change-default-storage-class/ |
Bare Metal Storage | https://medium.com/devityoself/kubernetes-bare-metal-storage-49b69d090dfa |
GlusterFS Native Storage Service for Kubernetes | https://github.com/gluster/gluster-kubernetes |