Usage

This document describes what’s needed to create and deploy a typical Model in Image domain.

Contents

WebLogic Kubernetes Operator

Deploy the operator and ensure that it is monitoring the desired namespace for your Model in Image domain. See Manage operators and Quick Start.

WebLogic Server image

Model in Image requires an image with a WebLogic Server installation.

  • You can start with WebLogic Server 12.2.1.4 or later, an Oracle Container Registry pre-built base image, such as container-registry.oracle.com/middleware/weblogic:12.2.1.4.

    The example base images are GA images and are suitable for demonstration and development purposes only where the environments are not available from the public Internet; they are not acceptable for production use. In production, you should always use CPU (patched) images from OCR or create your images using the WebLogic Image Tool (WIT) with the --recommendedPatches option. For more guidance, see Apply the Latest Patches and Updates in Securing a Production Environment for Oracle WebLogic Server.

    For an example of this approach, see the Model in Image sample. For detailed instructions on how to log in to the Oracle Container Registry and accept the license agreement for an image (required to allow pulling an Oracle Container Registry image), see this document.

  • Or, you can manually build your own base image, as described in Create a custom image with patches applied. This is useful if you want your base images to include additional patches. Note that any 12.2.1.3 image must also include patch 29135930 (the pre-built images already contain this patch).

    NOTE: As of December, 2022, Oracle will continue support of WebLogic Server 12.2.1.3, for six months only, for PSUs and security patches. CPU images for WebLogic Server 12.2.1.3 will be published in the January, 2023, and April, 2023, CPU cycles.

Directory structure

Model in Image requires the following directory structure in its pods for its (optional) WDT model artifacts and (required) WDT binaries:

Domain resource attribute Default directory Contents
domain.spec.configuration.model.modelHome /u01/wdt/models Zero or more model .yaml, .properties, and/or archive .zip files.
domain.spec.configuration.model.wdtInstallHome /u01/wdt/weblogic-deploy Unzipped WDT installation binaries (required).

Supplying initial model files and WDT

Model in Image minimally requires an image with a WebLogic installation (see WebLogic Server image), plus access to:

  • A WDT installation in domain.spec.configuration.model.wdtInstallHome.
  • One or more WDT model .yaml files that configure your domain in the domain.spec.configuration.model.modelHome directory or in the optional WDT model ConfigMap.
  • Zero or more WDT model .properties files in the domain.spec.configuration.model.modelHome directory or in the optional WDT model ConfigMap.
  • Zero or more WDT model application .zip archives in the domain.spec.configuration.model.modelHome directory. Archives must be supplied in the model home because application archives are not supported in the optional WDT model ConfigMap.

There are multiple methods for supplying Model in Image WDT artifacts:

  • Include in main image: You can include the artifacts in your domain resource domain.spec.image in its domain.spec.configuration.model.modelHome and domain.spec.configuration.model.wdtInstallHome directories as a layer on top of your base image (where the base image includes your WebLogic installation).

    Use either of the following methods.

    • Manual image creation uses Docker commands to layer the WDT artifacts, described in the previous table, on top of your base image into a new image.
    • The WebLogic Image Tool (WIT) has built-in options for layering WDT model files, WDT binaries, WebLogic Server binaries, and WebLogic Server patches in an image. The Model in Image sample uses the WIT approach.

  • Use auxiliary images: Use auxiliary images to create one or more small images that contain the desired files. This automatically copies files from each of the small images into each pod’s file system’s configuration.model.modelHome or configuration.model.wdtInstallHome location.

  • Use a Persistent Volume Claim (PVC): This method is for advanced use cases only. Supply WDT model YAML, variable, or archive files in a Persistent Volume Claim and modify configuration.model.modelHome and configuration.model.wdtInstallHome to the corresponding directory within the PVC’s mount location.

  • Use a WDT model ConfigMap: Use the Optional WDT model ConfigMap for WDT model YAML and .properties files. This can be combined with any of the previously mentioned methods and is most often used to facilitate runtime updates to models supplied by one of these methods.

For more information about model file syntax, see Model files.

Optional WDT model ConfigMap

You can create a WDT model ConfigMap that defines additional model .yaml and .properties files beyond what you’ve already supplied in your image, and then reference this ConfigMap using your Domain YAML file’s configuration.model.configMap attribute. This is optional if the supplied image already fully defines your model.

WDT model ConfigMap files will be merged with the WDT files defined in your image at runtime before your domain home is created. The ConfigMap files can add to, remove from, or alter the model configuration that you supplied within your image.

For example, place additional .yaml and .properties files in a directory called /home/acmeuser/wdtoverride and run the following commands:

$ kubectl -n MY-DOMAIN-NAMESPACE \
  create configmap MY-DOMAINUID-my-wdt-config-map \
  --from-file /home/acmeuser/wdtoverride

$ kubectl -n MY-DOMAIN-NAMESPACE \
  label  configmap MY-DOMAINUID-my-wdt-config-map \
  weblogic.domainUID=MY-DOMAINUID

See Model files for a description of model file syntax and loading order, and see Runtime updates for a description of using WDT model ConfigMaps to update the model configuration of a running domain.

Required runtime encryption secret

Model in Image requires a runtime encryption secret with a secure password key. This secret is used by the operator to encrypt model and domain home artifacts before it adds them to a runtime ConfigMap or log. You can safely change the password, at any time after you’ve fully shut down a domain, but it must remain the same for the life of a running domain. The runtime encryption secret that you create can be named anything, but note that it is a best practice to name and label secrets with their domain UID to help ensure that cleanup scripts can find and delete them.

NOTE: Because the runtime encryption password does not need to be shared and needs to exist only for the life of a domain, you may want to use a password generator.

Example:

$ kubectl -n MY-DOMAIN-NAMESPACE \
  create secret generic MY-DOMAINUID-runtime-encrypt-secret \
  --from-literal=password=welcome1

$ kubectl -n MY-DOMAIN-NAMESPACE \
  label secret MY-DOMAINUID-runtime-encrypt-secret \
  weblogic.domainUID=MY-DOMAINUID

Corresponding Domain YAML file snippet:

configuration:
  model:
    runtimeEncryptionSecret: MY-DOMAINUID-runtime-encrypt-secret

Secrets for model macros

Create additional secrets as needed by macros in your model files. For example, these can store database URLs and credentials that are accessed using @@SECRET macros in your model that reference the secrets. For a description of model macros, see Model files.

Domain fields

The following Domain fields are specific to Model in Image domains.

Domain Resource Attribute Notes
domainHomeSourceType Required. Set to FromModel.
domainHome Must reference an empty or non-existent directory within your image. Do not include the mount path of any persistent volume. Note that Model in Image recreates the domain home for a WebLogic Server pod every time the pod restarts.
configuration.model.configMap Optional. Set if you have stored additional models in a ConfigMap as per Optional WDT model ConfigMap.
configuration.secrets Optional. Set this array if your image or ConfigMap models contain macros that reference custom Kubernetes Secrets. For example, if your macros depend on secrets my-secret and my-other-secret, then set to [my-secret, my-other-secret].
configuration.model.runtimeEncryptionSecret Required. All Model in Image domains must specify a runtime encryption secret. See Required runtime encryption secret.
configuration.model.domainType Set the type of domain. WLS is the default. See WDT Domain Types.
configuration.model.runtimeEncryptionSecret Required. All Model in Image domains must specify a runtime encryption secret. See Required runtime encryption secret.
configuration.model.modelHome Optional. Location of the WDT model home, which can include model YAML files, .properties files, and application .zip archives. Defaults to /u01/wdt/models.
configuration.model.wdtInstallHome Optional. Location of the WDT install. Defaults to /u01/wdt/weblogic-deploy.

Notes:

  • There are additional attributes that are common to all domain home source types, such as the image field. See the Domain Resource schema and documentation for a full list of Domain fields.

  • There are also additional fields that are specific to JRF domain types. For more information, see Requirements for JRF domain types.

  • For fully specified Model in Image Domain YAML file examples, see the operator source directory kubernetes/samples/scripts/create-weblogic-domain/model-in-image/domain-resources for the Model in Image sample.

Always use external state

Regardless of the domain home source type, we recommend that you always keep state outside the image. This includes cluster database leasing tables, JMS and transaction stores, EJB timers, and so on. This ensures that data will not be lost when a container is destroyed.

We recommend that state be kept in a database to take advantage of built-in database server high availability features, and the fact that disaster recovery of sites across all but the shortest distances, almost always requires using a single database server to consolidate and replicate data (DataGuard).

For more information see: