Storage

Sample PersistentVolume and PersistentVolumeClaim

The sample scripts demonstrate the creation of a Kubernetes PersistentVolume (PV) and PersistentVolumeClaim (PVC), which can then be used in a Domain YAML file as a persistent storage for the WebLogic domain home or log files.

A PV and PVC can be shared by multiple WebLogic domains or dedicated to a particular domain.

Prerequisites

Before you begin, read this document, Persistent storage .

Using the scripts to create a PV and PVC

Prior to running the create-pv-pvc.sh script, make a copy of the create-pv-pvc-inputs.yaml file, and uncomment and explicitly configure the weblogicDomainStoragePath property in the inputs file.

Run the create script, pointing it at your inputs file and an output directory:

$ ./create-pv-pvc.sh \
  -i create-pv-pvc-inputs.yaml \
  -o /path/to/output-directory

The create-pv-pvc.sh script will create a subdirectory pv-pvcs under the given /path/to/output-directory directory. By default, the script generates two YAML files, namely weblogic-sample-pv.yaml and weblogic-sample-pvc.yaml, in the /path/to/output-directory/pv-pvcs. These two YAML files can be used to create the Kubernetes resources using the kubectl create -f command.

$ kubectl create -f weblogic-sample-pv.yaml

$ kubectl create -f weblogic-sample-pvc.yaml

As a convenience, the script can optionally create the PV and PVC resources using the -e option.

The usage of the create script is as follows:

$ sh create-pv-pvc.sh -h

usage: create-pv-pvc.sh -i file -o dir [-e] [-h]
  -i Parameter inputs file, must be specified.
  -o Output directory for the generated yaml files, must be specified.
  -e Also create the Kubernetes objects using the generated yaml files
  -h Help

If you copy the sample scripts to a different location, make sure that you copy everything in the <weblogic-kubernetes-operator-project>/kubernetes/samples/scripts directory together into the target directory, maintaining the original directory hierarchy.

Configuration parameters

The PV and PVC creation inputs can be customized by editing the create-pv-pvc-inputs.yaml file.

Parameter	Definition	Default
`domainUID`	ID of the Domain to which the generated PV and PVC will be dedicated. Leave it empty if the PV and PVC are going to be shared by multiple domains.	no default
`namespace`	Kubernetes Namespace to create the PVC.	`default`
`baseName`	Base name of the PV and PVC. The generated PV and PVC will be `<baseName>-pv` and `<baseName>-pvc` respectively.	`weblogic-sample`
`weblogicDomainStoragePath`	Physical path of the storage for the PV. When `weblogicDomainStorageType` is set to `HOST_PATH`, this value should be set the to path to the domain storage on the Kubernetes host. When `weblogicDomainStorageType` is set to NFS, then `weblogicDomainStorageNFSServer` should be set to the IP address or name of the DNS server, and this value should be set to the exported path on that server. Note that the path where the domain is mounted in the WebLogic containers is not affected by this setting; that is determined when you create your domain.	no default
`weblogicDomainStorageReclaimPolicy`	Kubernetes PVC policy for the persistent storage. The valid values are: `Retain`, `Delete`, and `Recycle`.	`Retain`
`weblogicDomainStorageSize`	Total storage allocated for the PVC.	`10Gi`
`weblogicDomainStorageType`	Type of storage. Legal values are `NFS` and `HOST_PATH`. If using `NFS`, `weblogicDomainStorageNFSServer` must be specified.	`HOST_PATH`
`weblogicDomainStorageNFSServer`	Name or IP address of the NFS server. This setting only applies if `weblogicDomainStorateType` is `NFS`.	no default

Shared versus dedicated PVC

By default, the domainUID is left empty in the inputs file, which means the generated PV and PVC will not be associated with a particular domain, but can be shared by multiple Domains in the same Kubernetes Namespaces as the PV and PVC. If the PV/PVC is being shared across domains, then, as a best practice, you should specify a unique baseName.

For the use cases where dedicated PV and PVC are desired for a particular domain, the domainUID needs to be set in the create-pv-pvc-inputs.yaml file. The presence of a non-empty domainUID in the inputs file will cause the generated PV and PVC to be associated with the specified domainUID. The association includes that the names of the generated YAML files and the Kubernetes PV and PVC objects are decorated with the domainUID, and the PV and PVC objects are also labeled with the domainUID.

Verify the results

The create script will verify that the PV and PVC were created, and will report a failure if there was any error. However, it may be desirable to manually verify the PV and PVC, even if just to gain familiarity with the various Kubernetes objects that were created by the script.

Generated YAML files with the default inputs

The content of the generated weblogic-sample-pvc.yaml:

# Copyright 2018, 2021, Oracle and/or its affiliates.
# Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: weblogic-sample-pvc
  namespace: default

  storageClassName: weblogic-sample-storage-class
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi

The content of the generated weblogic-sample-pv.yaml:

# Copyright 2018, 2021, Oracle and/or its affiliates.
# Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: weblogic-sample-pv
  # labels:
  #   weblogic.domainUID:
spec:
  storageClassName: weblogic-sample-storage-class
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  # Valid values are Retain, Delete or Recycle
  persistentVolumeReclaimPolicy: Retain
  hostPath:
  # nfs:
    # server: %SAMPLE_STORAGE_NFS_SERVER%
    path: "/scratch/k8s_dir"

Generated YAML files for dedicated PV and PVC

The content of the generated domain1-weblogic-sample-pvc.yaml when domainUID is set to domain1:

# Copyright 2018, 2021, Oracle and/or its affiliates.
# Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: domain1-weblogic-sample-pvc
  namespace: default
  labels:
    weblogic.domainUID: domain1
spec:
  storageClassName: domain1-weblogic-sample-storage-class
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi

The content of the generated domain1-weblogic-sample-pv.yaml when domainUID is set to domain1:

# Copyright 2018, 2021, Oracle and/or its affiliates.
# Licensed under the Universal Permissive License v 1.0 as shown at http://oss.oracle.com/licenses/upl.

apiVersion: v1
kind: PersistentVolume
metadata:
  name: domain1-weblogic-sample-pv
  labels:
    weblogic.domainUID: domain1
spec:
  storageClassName: domain1-weblogic-sample-storage-class
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  # Valid values are Retain, Delete or Recycle
  persistentVolumeReclaimPolicy: Retain
  hostPath:
  # nfs:
    # server: %SAMPLE_STORAGE_NFS_SERVER%
    path: "/scratch/k8s_dir"

Verify the PV and PVC objects

You can use this command to verify the PersistentVolume was created. Note that the Status field should have the value Bound, indicating the that PersistentVolume has been claimed:

$ kubectl describe pv weblogic-sample-pv

Name:            weblogic-sample-pv
Annotations:     pv.kubernetes.io/bound-by-controller=yes
StorageClass:    weblogic-sample-storage-class
Status:          Bound
Claim:           default/weblogic-sample-pvc
Reclaim Policy:  Retain
Access Modes:    RWX
Capacity:        10Gi
Message:         
Source:
    Type:          HostPath (bare host directory volume)
    Path:          /scratch/k8s_dir
    HostPathType:  
Events:            <none>

You can use this command to verify the PersistentVolumeClaim was created:

$ kubectl describe pvc weblogic-sample-pvc

Name:          weblogic-sample-pvc
Namespace:     default
StorageClass:  weblogic-sample-storage-class
Status:        Bound
Volume:        weblogic-sample-pv
Annotations:   pv.kubernetes.io/bind-completed=yes
               pv.kubernetes.io/bound-by-controller=yes
Finalizers:    []
Capacity:      10Gi
Access Modes:  RWX
Events:        <none>