nuriel77 / helm-nfs-server

Example of NFS as storageClass in K8S

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This link: https://github.com/helm/charts/tree/master/stable/nfs-server-provisioner

NFS Server Provisioner

NFS Server Provisioner is an out-of-tree dynamic provisioner for Kubernetes. You can use it to quickly & easily deploy shared storage that works almost anywhere.

This chart will deploy the Kubernetes external-storage projects nfs provisioner. This provisioner includes a built in NFS server, and is not intended for connecting to a pre-existing NFS server. If you have a pre-existing NFS Server, please consider using the NFS Client Provisioner instead.

TL;DR;

$ helm install stable/nfs-server-provisioner

Warning: While installing in the default configuration will work, any data stored on the dynamic volumes provisioned by this chart will not be persistent!

Introduction

This chart bootstraps a nfs-server-provisioner deployment on a Kubernetes cluster using the Helm package manager.

Installing the Chart

To install the chart with the release name my-release:

$ helm install stable/nfs-server-provisioner --name my-release

The command deploys nfs-server-provisioner on the Kubernetes cluster in the default configuration. The configuration section lists the parameters that can be configured during installation.

Uninstalling the Chart

To uninstall/delete the my-release deployment:

$ helm delete my-release

The command removes all the Kubernetes components associated with the chart and deletes the release.

Configuration

The following table lists the configurable parameters of the kibana chart and their default values.

Parameter	Description	Default
extraArgs	Additional command line arguments	{}
imagePullSecrets	Specify image pull secrets	nil (does not add image pull secrets to deployed pods)
image.repository	The image repository to pull from	quay.io/kubernetes_incubator/nfs-provisioner
image.tag	The image tag to pull from	v2.2.2
image.pullPolicy	Image pull policy	IfNotPresent
service.type	service type	ClusterIP
service.nfsPort	TCP port on which the nfs-server-provisioner NFS service is exposed	2049
service.mountdPort	TCP port on which the nfs-server-provisioner mountd service is exposed	20048
service.rpcbindPort	TCP port on which the nfs-server-provisioner RPC service is exposed	111
service.nfsNodePort	if service.type is NodePort and this is non-empty, sets the nfs-server-provisioner node port of the NFS service	nil
service.mountdNodePort	if service.type is NodePort and this is non-empty, sets the nfs-server-provisioner node port of the mountd service	nil
service.rpcbindNodePort	if service.type is NodePort and this is non-empty, sets the nfs-server-provisioner node port of the RPC service	nil
persistence.enabled	Enable config persistence using PVC	false
persistence.storageClass	PVC Storage Class for config volume	nil
persistence.accessMode	PVC Access Mode for config volume	ReadWriteOnce
persistence.size	PVC Storage Request for config volume	1Gi
storageClass.create	Enable creation of a StorageClass to consume this nfs-server-provisioner instance	true
storageClass.provisionerName	The provisioner name for the storageclass	cluster.local/{release-name}-{chart-name}
storageClass.defaultClass	Whether to set the created StorageClass as the clusters default StorageClass	false
storageClass.name	The name to assign the created StorageClass	nfs
storageClass.allowVolumeExpansion	Allow base storage PCV to be dynamically resizeable (set to null to disable )	`true
storageClass.parameters	Parameters for StorageClass	{}
storageClass.mountOptions	Mount options for StorageClass	[ "vers=3" ]
storageClass.reclaimPolicy	ReclaimPolicy field of the class, which can be either Delete or Retain	Delete
resources	Resource limits for nfs-server-provisioner pod	{}
nodeSelector	Map of node labels for pod assignment	{}
tolerations	List of node taints to tolerate	[]
affinity	Map of node/pod affinities	{}
podSecurityContext	Security context settings for nfs-server-provisioner pod (see https://kubernetes.io/docs/tasks/configure-pod-container/security-context/#set-the-security-context-for-a-pod)	{}

$ helm install stable/nfs-server-provisioner --name my-release \
  --set=image.tag=v1.0.8,resources.limits.cpu=200m

Alternatively, a YAML file that specifies the values for the above parameters can be provided while installing the chart. For example,

$ helm install stable/nfs-server-provisioner --name my-release -f values.yaml

Tip: You can use the default values.yaml as an example

Persistence

The nfs-server-provisioner image stores it's configuration data, and importantly, the dynamic volumes it manages /export path of the container.

The chart mounts a Persistent Volume volume at this location. The volume can be created using dynamic volume provisioning. However, it is highly recommended to explicitly specify a storageclass to use rather than accept the clusters default, or pre-create a volume for each replica.

If this chart is deployed with more than 1 replica, storageClass.defaultClass=true and persistence.storageClass, then the 2nd+ replica will end up using the 1st replica to provision storage - which is likely never a desired outcome.

Recommended Persistence Configuration Examples

The following is a recommended configuration example when another storage class exists to provide persistence:

persistence:
  enabled: true
  storageClass: "standard"
  size: 200Gi

storageClass:
  defaultClass: true

On many clusters, the cloud provider integration will create a "standard" storage class which will create a volume (e.g. a Google Compute Engine Persistent Disk or Amazon EBS volume) to provide persistence.

---

The following is a recommended configuration example when another storage class does not exist to provide persistence:

persistence:
  enabled: true
  storageClass: "-"
  size: 200Gi

storageClass:
  defaultClass: true

In this configuration, a PersistentVolume must be created for each replica to use. Installing the Helm chart, and then inspecting the PersistentVolumeClaim's created will provide the necessary names for your PersistentVolume's to bind to.

An example of the necessary PersistentVolume:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: data-nfs-server-provisioner-0
spec:
  capacity:
    storage: 200Gi
  accessModes:
    - ReadWriteOnce
  gcePersistentDisk:
    fsType: "ext4"
    pdName: "data-nfs-server-provisioner-0"
  claimRef:
    namespace: kube-system
    name: data-nfs-server-provisioner-0

---

The following is a recommended configration example for running on bare metal with a hostPath volume:

persistence:
  enabled: true
  storageClass: "-"
  size: 200Gi

storageClass:
  defaultClass: true

nodeSelector:
  kubernetes.io/hostname: {node-name}

In this configuration, a PersistentVolume must be created for each replica to use. Installing the Helm chart, and then inspecting the PersistentVolumeClaim's created will provide the necessary names for your PersistentVolume's to bind to.

An example of the necessary PersistentVolume:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: data-nfs-server-provisioner-0
spec:
  capacity:
    storage: 200Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: /srv/volumes/data-nfs-server-provisioner-0
  claimRef:
    namespace: kube-system
    name: data-nfs-server-provisioner-0

Warning: hostPath volumes cannot be migrated between machines by Kubernetes, as such, in this example, we have restricted the nfs-server-provisioner pod to run on a single node. This is unsuitable for production deployments.