PersistentVolumeClaims
To run HCL Digital Experience 9.5 Container deployments in your Kubernetes or OpenShift cluster, you need to set up PersistentVolumes (PVs) on your cluster and configure the Helm Chart to create the appropriate PersistentVolumeClaims (PVCs).
Before you proceed, review the Persistent Volumes and related operations considerations topic in the DX Help Center.
Note
The provisioning of PersistentVolumes (PVs) may differ based on your cluster configuration and your cloud provider. Please reference the documentation of your cloud provider for additional information.
Persistent Volume Types
Important
Ensure that your PersistentVolumes (PVs) are created with the Reclaim Policy set to RETAIN. This allows for the reuse of PVs after a PersistentVolumeClaim (PVC) is deleted. This is important to keep data persisted, for example, between deployments or tests. Refrain from using the Reclaim Policy DELETE unless you have the experience in managing these operations successfully, to avoid unpredictable results. This is not recommended in production use, as deleting PVCs causes the Kubernetes or OpenShift cluster to delete the bound PV as well, thus, deleting all the data on it.
-
ReadWriteOnce
(RWO)ReadWriteOnce
PVs allow only one pod per volume to perform reading and writing transactions. This means that the data on that PV cannot be shared with other pods and is linked to one pod at a time.In the HCL Digital Experience 9.5 Kubernetes or OpenShift deployment using Helm, the only DX applications leveraging RWO PVs are Core and Persistence.
Information regarding how to calculate the number of required volumes for the DX Core and Persistence applications is presented in the Persistent Volumes and related operations considerations topic in the DX Help Center.
Since Core requires RWO PVs per pod, it may be necessary to have auto-provisioning of such volumes configured in your cluster if you don't know the final maximum number of possible Core pods running at the same time. Each Core pod requires 2 RWO PVs.
Since the number of pods for Persistence is limited by design, you need 2 RWO PVs for Persistence.
-
ReadWriteMany
(RWX)ReadWriteMany
PVs support read and write operations by multiple pods. This means the data on that PV can be shared with other pods and can be linked to multiple pods at a time.In the HCL Digital Experience 9.5 Kubernetes and OpenShift deployment using Helm the only DX applications leveraging RWX PVs are Core and Digital Asset Management.
Since the PV can be shared between all Core pods, you need one (1) RWX PV for Core, regardless of the pod count. Since the PV can be shared between all Digital Asset Management pods, you need one (1) RWX PV for Digital Asset Management, regardless of the pod count.
Configuration parameters
To access the PersistentVolumes (PVs) on your cluster, the HCL Digital Experience 9.5 Kubernetes or OpenShift deployment using Helm creates PersistentVolumeClaims (PVCs) that binds the PVs to the corresponding pods.
Each PVC that applications require allows you to configure the following parameters, as shown below. For a PVC of the Core application:
# Persistent Volume Setup
volumes:
# Persistent Volumes for Core
core:
# Shared profile PVC shared by all Core pods
profile:
storageClassName: "manual"
requests:
storage: "10Gi"
# Optional volume name to specifically map to
volumeName:
Important
Make sure to properly define the PVC configuration in your custom-values.yaml file before running the deployment. This avoids issues when trying to get your deployment up and running.
-
StorageClassName
Depending on your Cluster configuration, you may have configured a specific
StorageClass
that should be used for your PVs and the PVCs of HCL Digital Experience.This property allows you to enter the name of the
StorageClass
you want the deployment to use. PVCs then only accepts PVs that match theStorageClassName
you have defined in the configuration. If there are no PVs that match, the pods remain pending and do not start until a fitting PV is provided by the cluster.If you enter an empty
StorageClassName
, Kubernetes falls back to the defaultStorageClass
configured in your Cluster. Refer to your cloud provider for additional information about your default StorageClass, since this depends on your Kubernetes or OpenShift environment.Reference the original values.yaml file you have extracted as outlined in the Prepare configuration topic for all configurable PVCs.
-
Requests
Storage
Storage allows you to define the amount of space that is required by the PVC. Once defined, it only accepts PVs that have the same or more storage capacity as requested. If there are no PVs matching the definitions, the pods remain pending and do not start until a properly-sized PV is provided by the cluster.
-
Selector
If you want your deployment to pick up specific PVs that you have created, the
selector
option can be used to match PVs by their labels.A detailed description on how to use the
selector
can be found in the officialKubernetes
documentation.A PVC will only match with a PV satisfying the selector and all the other requirements such as type (
RWO/RWX
, as defined by the deployment itself), storage capacity, andStorageClassName
. -
VolumeName
If you want your deployment to pick up a specific PV that you have created, use of the
VolumeName
can define that instruction. Ensure that the PV you created has a unique name. Then, add that name as a configuration parameter for the PVC.The PVCs only matches with a PV of that name, matching the other requirements-like type (
RWO/RWX
, as defined by the deployment itself), storage capacity, andStorageClassName
.Important
As a single persistent Volume is assigned using the
volumeName
, this should only be used forRWX
claims or for Pods that are only ever scaled to one replica.If a second
PersistentVolumeClaim
is created with the samevolumeName
, it can never be fulfilled as the names for Volumes are unique. Please refer to theSelector
section to select specificPersistentVolumes
for multiple claims.
Sample PVC configurations
The following are some examples for configuration of the PersistentVolumeClaims (PVCs) using your custom-values.yaml:
Fallback to default StorageClass
for all applications
Leaving an empty StorageClassName
causes Kubernetes or OpenShift to fall back to the StorageClass
that has been configured as the default one in your cluster:
# Persistent Volume Setup
volumes:
# Persistent Volumes for Core
core:
# Shared profile PVC shared by all Core pods
profile:
storageClassName: ""
# Transaction Log PVC, one per Core pod
tranlog:
storageClassName: ""
# Application Log PVC, one per Core pod
log:
storageClassName: ""
# Persistent Volumes for Digital Asset Management
digitalAssetManagement:
# Binary storage PVC, shared by all Digital Asset Management Pods
binaries:
storageClassName: ""
# Persistent Volumes for Persistence
persistence:
# Database PVC, one per Persistence pod
database:
storageClassName: ""
# Persistent Volumes for Open LDAP
openLdap:
# slapd directory PVC, one per Open LDAP pod
slapd:
storageClassName: ""
# certificate directory, on per Open LDAP pod
certificate:
storageClassName: ""
# ldap directory PVC, one per Open LDAP pod
ldap:
storageClassName: ""
# Persistent Volumes for Remote Search
remoteSearch:
# Remote Search profile PVC, one per Remote Search pod
prsprofile:
storageClassName: ""
Specific StorageClasses for all applications
Setting the StorageClassName
to mycloudstorage
causes Kubernetes or OpenShift to create PVCs that only accepts PVs with the StorageClass
mycloudstorage
:
# Persistent Volume Setup
volumes:
# Persistent Volumes for Core
core:
# Shared profile PVC shared by all Core pods
profile:
storageClassName: "mycloudstorage"
# Transaction Log PVC, one per Core pod
tranlog:
storageClassName: "mycloudstorage"
# Application Log PVC, one per Core pod
log:
storageClassName: "mycloudstorage"
# Persistent Volumes for Digital Asset Management
digitalAssetManagement:
# Binary storage PVC, shared by all Digital Asset Management Pods
binaries:
storageClassName: "mycloudstorage"
# Persistent Volumes for Persistence
persistence:
# Database PVC, one per Persistence pod
database:
storageClassName: "mycloudstorage"
# Persistent Volumes for Open LDAP
openLdap:
# slapd directory PVC, one per Open LDAP pod
slapd:
storageClassName: "mycloudstorage"
# certificate directory, on per Open LDAP pod
certificate:
storageClassName: "mycloudstorage"
# ldap directory PVC, one per Open LDAP pod
ldap:
storageClassName: "mycloudstorage"
# Persistent Volumes for Remote Search
remoteSearch:
# Remote Search profile PVC, one per Remote Search pod
prsprofile:
storageClassName: "mycloudstorage"
Specific volumes using selectors and labels
In the custom-values.yaml file, set the selectors for a specific application. In this example, the persistenceNode
is used.
volumes:
# Persistent Volumes for Persistence Node
persistenceNode:
# Database PVC, one per persistence node
database:
# Optional label selector to further filter the set of volumes. Only the volumes whose labels match the selector can be bound to the claim.
selector:
matchLabels:
myVolumeLabel: persistence-node
By default, 3 replicas of persistenceNode
are created. To make sure all PersistenceVolumeClaims
are satisfied, we need to create at least 3 PersistentVolumes
with matching labels.
Each PersistentVolume
should look similar to the following example:
apiVersion: v1
kind: PersistentVolume
metadata:
name: persistence-node-volume-0
labels:
myVolumeLabel: persistence-node
spec:
capacity:
storage: 100Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: mycloudstorage
This will make sure that one of the persistenceNode
Pods will pick up the Volume. To ensure an exact 1 to 1 match between Volume and Claim, refer to the "Reserving a PersistentVolume" documentation for Kubernetes to set a claimRef
in the PersistentVolume
in addition to the selectors.
apiVersion: v1
kind: PersistentVolume
metadata:
name: persistence-node-volume-0
labels:
myVolumeLabel: persistence-node
spec:
capacity:
storage: 100Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: mycloudstorage
claimRef:
name: database-dx-deployment-persistence-node-0
namespace: myDXNamespace
This will ensure that only the dx-deployment-persistence-node-0
Pod and none of the other replicas will use this PersistentVolume
.
Specific volume names
Specifying a name ensures that Kubernetes or OpenShift only assigns PVs with the matching name to the PVCs created for the applications:
# Persistent Volume Setup
volumes:
# Persistent Volumes for Core
core:
# Shared profile PVC shared by all Core pods
profile:
storageClassName: "mycloudstorage"
# Optional volume name to specifically map to
volumeName: "core-profile"
# Persistent Volumes for Digital Asset Management
digitalAssetManagement:
# Binary storage PVC, shared by all Digital Asset Management Pods
binaries:
storageClassName: "mycloudstorage"
# Optional volume name to specifically map to
volumeName: "dam-binaries"
Adjusted volume size for Core PVCs
You may override the default sizes for PVCs by adjusting the storage requests:
# Persistent Volume Setup
volumes:
# Persistent Volumes for Core
core:
# Shared profile PVC shared by all Core pods
profile:
storageClassName: "mycloudstorage"
requests:
storage: "150Gi"
# Transaction Log PVC, one per Core pod
tranlog:
storageClassName: "mycloudstorage"
requests:
storage: "1Gi"
# Application Log PVC, one per Core pod
log:
storageClassName: "mycloudstorage"
requests:
storage: "1Gi"
Sample Persistent Volume definitions
Sample StorageClass
It is recommended to have a separate StorageClass
for HCL Digital Experience 9.5 deployments in order to prevent other deployed applications in the same Kubernetes or OpenShift cluster to interfere with Persistent Volumes (PVs) that should only be used by HCL Digital Experience.
The following example shows a StorageClass
with the name dx-deploy-stg
that can be created in your cluster for that purpose:
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: dx-deploy-stg
provisioner: kubernetes.io/no-provisioner
reclaimPolicy: Retain
volumeBindingMode: WaitForFirstConsumer
Applying this yaml on your Kubernetes or OpenShift cluster creates the StorageClass
as a cluster-wide resource.
Sample Persistent Volume
To leverage the StorageClass
you created, you can use the following Persistent Volume example, which connects to an NFS Server of your choice to provide a PV:
kind: PersistentVolume
apiVersion: v1
metadata:
name: wp-profile-volume
spec:
capacity:
storage: 100Gi
nfs:
server: your_nfs_server.com
path: /exports/volume_name
accessModes:
- ReadWriteMany
persistentVolumeReclaimPolicy: Retain
storageClassName: dx-deploy-stg
mountOptions:
- hard
- nfsvers=4.1
- rsize=8388608
- wsize=8388608
- timeo=600
- retrans=2
- noresvport
volumeMode: Filesystem
Configuring additional core persistent volumes
A HCL Digital Experience Kubernetes deployment requires a number of persistent volumes as standard, such as for the Core profile and for digital asset storage. It is now also possible to connect additional persistent volumes to the Core stateful set and mount them in the main container of all Core pods. It is anticipated that this optional feature will be of use to customers running custom applications on DX that require additional persistent storage.
This feature allows you to configure additional Persistent Volume Claims (PVCs) for the Core stateful set and specify the directories at which they will be mounted in the main containers of all Core pods.
Important
Core pods will remain "Pending" until all the new claims have been satisfied. Please ensure that you have created the necessary Persistent Volumes in advance or have suitable provisioners in your Kubernetes cluster to create the volumes on demand.
The following syntax can be used to configure additional Persistent Volume Claims (PVCs) in your custom-values.yaml
:
volumes:
# Persistent Volumes for Core
core:
# List of optional additional Core PVCs for customer applications
# Each list element must include a unique "name", one or more "accessModes"
# from the options ReadWriteOnce, ReadOnlyMany or ReadWriteMany, a "mountPath" specifying where in the
# core container it should be mounted, a "storageClassName" and a size in "requests/storage".
# It may also optionally include a "selector" section to select specific PVs based on their labels.
# It may also optionally include a "volumeName" to select a specific PV.
# Example:
# customPVCs:
# - name: "test1"
# accessModes:
# - "ReadWriteMany"
# mountPath: "/opt/HCL/test1"
# storageClassName: "manual"
# requests:
# storage: "20Gi"
# selector:
# matchLabels:
# label: test
# matchExpressions:
# - key: name
# operator: In
# values:
# - test1
# - test2
# volumeName: "test-pv"
customPVCs: []
Example
The following example creates a new PVC called <deployment-name>-core-custom-test1
and mounts it in the main Core pod containers at /opt/HCL/test1
. To be satisfied this claim requires a Persistent Volume with access mode ReadWriteOnce
, storage class manual
and at least 20Gb capacity. Since volumeName
and selector
are not specified, Kubernetes is free to choose any unbound volume that meets the above criteria.
volumes:
core:
customPVCs:
- name: "test1"
accessModes:
- "ReadWriteOnce"
mountPath: "/opt/HCL/test1"
storageClassName: "manual"
requests:
storage: "20Gi"