Model in Image
This sample demonstrates how to use the WebLogic Kubernetes Operator (hereafter “the operator”) to set up a WebLogic Server (WLS) cluster on the Azure Kubernetes Service (AKS) using the model in image domain home source type. After going through the steps, your WLS domain runs on an AKS cluster instance and you can manage your WLS domain by interacting with the operator.
Contents
Prerequisites
This sample assumes the following prerequisite environment.
- If you don’t have an
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Azure subscription , create a
target="_blank” rel=“noopener noreferrer”
free account before you begin.
- It’s recommended that the Azure identity you use to sign in and complete this article has either the
<a href=“ https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#owner"
target="_blank” rel=“noopener noreferrer”
Owner role in the current subscription or the
<a href=“ https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#contributor"
target="_blank” rel=“noopener noreferrer”
Contributor and
target="_blank” rel=“noopener noreferrer”
User Access Administrator roles in the current subscription.
- If your identity has very limited role assignments, ensure you have
<a href=“ https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles#contributor"
target="_blank” rel=“noopener noreferrer”
Contributor role and
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User Access Administrator role in the resource group that runs the AKS cluster. This requires asking a privileged user to assign the roles before creating resources in the resource group.
- It’s recommended that the Azure identity you use to sign in and complete this article has either the
- Operating System: GNU/Linux, macOS (Intel only, Apple Silicon not supported),
<a href=“ https://learn.microsoft.com/windows/wsl/install"
target="_blank” rel=“noopener noreferrer”
Windows Subsystem for Linux (WSL) .
-
<a href=“ https://git-scm.com/downloads"
target="_blank” rel=“noopener noreferrer”
Git ; use
git –versionto test ifgitworks. This document was tested with version 2.25.1. -
<a href=“ https://docs.microsoft.com/cli/azure"
target="_blank” rel=“noopener noreferrer”
Azure CLI ; use
az –versionto test ifazworks. This document was tested with version 2.58.0. -
<a href=“ https://www.docker.com/products/docker-desktop"
target="_blank” rel=“noopener noreferrer”
Docker for Desktop . This document was tested with
Docker version 20.10.7. -
<a href=“ https://kubernetes-io-vnext-staging.netlify.com/docs/tasks/tools/install-kubectl/"
target="_blank” rel=“noopener noreferrer”
kubectl ; use
kubectl versionto test ifkubectlworks. This document was tested with version v1.21.2. -
<a href=“ https://helm.sh/docs/intro/install/"
target="_blank” rel=“noopener noreferrer”
Helm , version 3.1 and later; use
helm versionto check thehelmversion. This document was tested with version v3.6.2. - A JDK, version 8 or 11. Azure recommends
<a href=“ https://docs.microsoft.com/java/openjdk/download"
target="_blank” rel=“noopener noreferrer”
Microsoft Build of OpenJDK . Ensure that your
JAVA_HOMEenvironment variable is set correctly in the shells in which you run the commands. - Ensure that you have the zip/unzip utility installed; use
zip/unzip -vto test ifzip/unzipworks. - You will need an Oracle account.
Prepare parameters
Set required parameters by running the following commands.
Oracle Container Registry
The following steps will direct you to accept the license agreement for WebLogic Server. Make note of your Oracle Account password and email. This sample pertains to 12.2.1.4, but other versions may work as well.
- In a web browser, navigate to
<a href=“ https://container-registry.oracle.com ”
target="_blank" rel=“noopener noreferrer”
https://container-registry.oracle.com and log in using the Oracle Single Sign-On authentication service. If you do not already have SSO credentials, at the top of the page, click the Sign In link to create them.
- The Oracle Container Registry provides a WebLogic 12.2.1.4 General Availability (GA) installation image that is used in this sample.
- In the Oracle Container Registry, navigate to Middleware, then weblogic.
- On the left, choose a language and accept the license agreement. You will then see a message such as: “You last accepted the Oracle Standard Terms and Restrictions on 08/10/2020 at 06:12 AM Coordinated Universal Time (UTC).”
- NOTE: General Availability (GA) images 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 the OCR
or create your images using the
<a href=“ https://oracle.github.io/weblogic-image-tool/userguide/tools/create-image/"
target="_blank” rel=“noopener noreferrer”
WebLogic Image Tool
(WIT) with the
–recommendedPatchesoption. For more guidance, seetarget="_blank” rel=“noopener noreferrer”
Apply the Latest Patches and Updates
in Securing a Production Environment for Oracle WebLogic Server.
- Ensure that Docker is running. Find and pull the WebLogic 12.2.1.4 installation image:
If you have problems accessing the Oracle Container Registry, you can build your own images from the
<a href=“ https://github.com/oracle/docker-images/tree/main/OracleWebLogic/dockerfiles"
target="_blank” rel=“noopener noreferrer”
Oracle GitHub repository .
Sign in with Azure CLI
The steps in this section show you how to sign in to the Azure CLI.
-
Open a Bash shell.
-
Sign out and delete some authentication files to remove any lingering credentials.
-
Sign in to your Azure CLI.
-
Set the subscription ID. Be sure to replace the placeholder with the appropriate value.
Download the WebLogic Kubernetes Operator sample
Download the WebLogic Kubernetes Operator sample ZIP file. We will use several scripts in this zip file to create a WebLogic domain. This sample was tested with v4.2.8, but should work with the latest release.
Create Resource Group
Create the resource group by issuing the following commands.
Create the AKS cluster
This sample doesn’t enable application routing. If you want to enable application routing, follow
<a href=“ https://learn.microsoft.com/azure/aks/app-routing?tabs=default%2Cdeploy-app-default"
target="_blank” rel=“noopener noreferrer”
Managed nginx Ingress with the application routing add-on in AKS .
Run the following command to create the AKS cluster.
Successful output will be a JSON object with the entry "type": "Microsoft.ContainerService/ManagedClusters".
After the deployment finishes, run the following command to connect to the AKS cluster. This command updates your local ~/.kube/config so that subsequent kubectl commands interact with the named AKS cluster.
Successful output will look similar to:
After your Kubernetes cluster is up and running, run the following commands to make sure kubectl can access the Kubernetes cluster:
Successful output will look like the following.
NOTE: If you run into VM size failure, see Troubleshooting - Virtual Machine size is not supported .
Install WebLogic Kubernetes Operator
The WebLogic Kubernetes Operator is an adapter to integrate WebLogic Server and Kubernetes, allowing Kubernetes to serve as container infrastructure hosting WLS instances. The operator runs as a Kubernetes Pod and stands ready to perform actions related to running WLS on Kubernetes.
Create a namespace and service account for the operator.
The output will show something similar to the following:
The output will show something similar to the following:
Validate the service account was created with this command.
The output will show something similar to the following:
Install the operator. The operator’s Helm chart is located in the kubernetes/charts/weblogic-operator directory. This sample installs the operator using Helm charts from GitHub. It may take you several minutes to install the operator.
Update the repo to get the latest Helm charts. It is a best practice to do this every time before installing a new operator version. In this example, we are using a pinned version, but you may also find success if you use the latest version. In this case, you can omit the --version argument. Be warned that these instructions have only been tested with the exact version shown.
The output will show something similar to the following:
Tip
If you wish to use a more recent version of the operator, replace the 4.2.8 in the preceding command with the other version number. To see the list of versions, visit the
GitHub releases page
.
Verify the operator with the following commands; the status will be Running.
The output will show something similar to the following:
The output will show something similar to the following:
Note
You can specify the operator image by changing value of --set image. If you run into failures, see
Troubleshooting - WebLogic Kubernetes Operator installation failure
.
Info
If you have an image built with domain models following Model in Image , you can go to Create WebLogic domain directly.
Create Docker image
Image creation prerequisites
-
The
JAVA_HOMEenvironment variable must be set and must reference a valid JDK 8 or 11 installation. -
Copy the sample to a new directory; for example, use the directory
/tmp/mii-sample. In the directory name,miiis short for “model in image”. Model in image is one of three domain home source types supported by the operator. To learn more, see Choose a domain home source type .Save the model file directory.
NOTE: We will refer to this working copy of the sample as
/tmp/mii-sample; however, you can use a different location.
-
Download the latest WebLogic Deploying Tooling (WDT) and WebLogic Image Tool (WIT) installer ZIP files to your
${WDT_MODEL_FILES_PATH}directory. Both WDT and WIT are required to create your Model in Image images. -
Set up the WebLogic Image Tool, run the following commands:
These steps will install WIT to the
${WDT_MODEL_FILES_PATH}/imagetooldirectory, plus put awdt_latestentry in the tool’s cache which points to the WDT ZIP file installer. You will use WIT later in the sample for creating model images.
Image creation - Introduction
The goal of image creation is to demonstrate using the WebLogic Image Tool to create an image tagged as wdt-domain-image:WLS-v1 from files that you will stage to ${WDT_MODEL_FILES_PATH}/WLS-v1/.
- The directory where the WebLogic Deploy Tooling software is installed (also known as WDT Home) is expected in an image’s
/auxiliary/weblogic-deploydirectory. - WDT model YAML (model), WDT variable (property), and WDT archive ZIP (archive) files are expected in directory
/auxiliary/models.
Understanding your first archive
See Understanding your first archive .
Staging a ZIP file of the archive
When you create the image, you will use the files in the staging directory, ${WDT_MODEL_FILES_PATH}/WLS-v1. In preparation, you need it to contain a ZIP file of the WDT application archive.
Run the following commands to create your application archive ZIP file and put it in the expected directory:
Create a ZIP file of the archive in the location that we will use when we run the WebLogic Image Tool.
Staging model files
In this step, you explore the staged WDT model YAML file and properties in the ${WDT_MODEL_FILES_PATH}/WLS-v1 directory. The model in this directory references the web application in your archive, configures a WebLogic Server Administration Server, and configures a WebLogic cluster. It consists of only two files, model.10.properties, a file with a single property, and, model.10.yaml, a YAML file with your WebLogic configuration.
Here is the WLS model.10.properties:
Here is the WLS model.10.yaml:
The model file:
-
Defines a WebLogic domain with:
- Cluster
cluster-1 - Administration Server
admin-server - An EAR application, targeted to
cluster-1, located in the WDT archive ZIP file atwlsdeploy/applications/myapp-v1
- Cluster
-
Leverages macros to inject external values:
- The property file
CLUSTER_SIZEproperty is referenced in the model YAML fileDynamicClusterSizeandMaxDynamicClusterSizefields using a PROP macro. - The model file domain name is injected using a custom environment variable named
CUSTOM_DOMAIN_NAMEusing an ENV macro.- You set this environment variable later in this sample using an
envfield in its Domain. - This conveniently provides a simple way to deploy multiple differently named domains using the same model image.
- You set this environment variable later in this sample using an
- The model file administrator user name and password are set using a
weblogic-credentialssecret macro reference to the WebLogic credential secret.- This secret is in turn referenced using the
webLogicCredentialsSecretfield in the Domain. - The
weblogic-credentialsis a reserved name that always dereferences to the owning Domain actual WebLogic credentials secret name.
- This secret is in turn referenced using the
- The property file
A Model in Image image can contain multiple properties files, archive ZIP files, and YAML files but in this sample you use just one of each. For a complete description of Model in Images model file naming conventions, file loading order, and macro syntax, see Model files in the Model in Image user documentation.
Creating the image with WIT
At this point, you have all of the files needed for image wdt-domain-image:WLS-v1 staged; they include:
/tmp/sample/wdt-artifacts/wdt-model-files/WLS-v1/model.10.yaml/tmp/sample/wdt-artifacts/wdt-model-files/WLS-v1/model.10.properties/tmp/sample/wdt-artifacts/wdt-model-files/WLS-v1/archive.zip
Now, you use the Image Tool to create an image named wdt-domain-image:WLS-v1. You’ve already set up this tool during the prerequisite steps.
Run the following command to create the image and verify that it worked.
This command runs the WebLogic Image Tool to create the domain creation image and does the following:
- Builds the final container image as a layer on a small
busyboxbase image. - Copies the WDT ZIP file that’s referenced in the WIT cache into the image.
- Note that you cached WDT in WIT using the keyword
latestwhen you set up the cache during the sample prerequisites steps. - This lets WIT implicitly assume it’s the desired WDT version and removes the need to pass a
-wdtVersionflag.
- Note that you cached WDT in WIT using the keyword
- Copies the specified WDT model, properties, and application archives to image location
/auxiliary/models.
When the command succeeds, it should end with output like the following:
Verify the image is available in the local Docker server with the following command.
The output will show something similar to the following:
Note
The imagetool.sh is not supported on macOS with Apple Silicon. See
Troubleshooting - exec format error
.
Note
You may run into a Dockerfile parsing error if your Docker buildkit is enabled, see
Troubleshooting - WebLogic Image Tool failure
.
Pushing the image to Azure Container Registry
AKS can pull images from any container registry, but the easiest integration is to use Azure Container Registry (ACR). In addition to simplicity, using ACR simplifies high availability and disaster recovery with features such as geo-replication. For more information, see
<a href=“ https://learn.microsoft.com/en-us/azure/container-registry/container-registry-geo-replication"
target="_blank” rel=“noopener noreferrer”
Geo-replication in Azure Container Registry . In this section, we will create a new Azure Container Registry, connect it to our pre-existing AKS cluster and push the image built in the preceding section to it. For complete details, see
<a href=“ https://learn.microsoft.com/en-us/azure/container-registry/"
target="_blank” rel=“noopener noreferrer”
Azure Container Registry documentation .
Let’s create an instance of ACR in the same resource group we used for AKS. We will use the environment variables used during the steps above. For simplicity, we use the resource group name as the name of the ACR instance.
Closely examine the JSON output from this command. Save the value of the loginServer property aside. It will look something like the following.
Use this value to sign in to the ACR instance. Note that because you are signing in with the az CLI, you do not need a password because your identity is already conveyed by having done az login previously.
Successful output will include Login Succeeded.
Ensure Docker is running on your local machine. Run the following commands to tag and push the image to your ACR.
The output will show something similar to the following:
Finally, connect the AKS cluster to the ACR. For more details on connecting ACR to an existing AKS, see
target="_blank” rel=“noopener noreferrer”
Configure ACR integration for existing AKS clusters .
Successful output will be a JSON object with the entry "type": "Microsoft.ContainerService/ManagedClusters".
If you see an error that seems related to you not being an Owner on this subscription, please refer to the troubleshooting section Cannot attach ACR due to not being Owner of subscription .
Create WebLogic domain
In this section, you will deploy the new image to the namespace sample-domain1-ns, including the following steps:
- Create a namespace for the WebLogic domain.
- Upgrade the operator to manage the WebLogic domain namespace.
- Create a secret containing your WebLogic administrator user name and password.
- Create a secret containing your Model in Image runtime encryption password:
- All Model in Image domains must supply a runtime encryption Secret with a
passwordvalue. - The runtime encryption password is used to encrypt configuration that is passed around internally by the operator.
- The value must be kept private but can be arbitrary; you can optionally supply a different secret value every time you restart the domain.
- All Model in Image domains must supply a runtime encryption Secret with a
- Deploy a domain YAML file that references the new image.
- Wait for the domain’s pods to start and reach their ready state.
Namespace
Create a namespace that can host one or more domains:
Label the domain namespace so that the operator can autodetect and create WebLogic Server pods. Without this step, the operator cannot see the namespace.
Kubernetes Secrets for WebLogic image
You will use the kubernetes/samples/scripts/create-kubernetes-secrets/create-docker-credentials-secret.sh script to create the Docker credentials as a Kubernetes secret to pull image from OCR. Please run:
The output will show something similar to the following:
Kubernetes Secrets for WebLogic
First, create the secrets needed by the WLS type model domain. For more on secrets in the context of running domains, see Prepare to run a domain . In this case, you have two secrets.
Run the following kubectl commands to deploy the required secrets:
Some important details about these secrets:
-
Make sure to enclose your values in double quotes and perform the necessary escaping to prevent the shell from modifying the values before the secret values are set.
-
Choosing passwords and user names:
- Set the variables
WEBLOGIC_USERNAMEandWEBLOGIC_PASSWORDwith a user name and password of your choice. The password should be at least eight characters long and include at least one digit. Remember what you specified. These credentials may be needed again later. - Set the variable
WEBLOGIC_WDT_PASSWORDwith a password of your choice.
- Set the variables
-
The WebLogic credentials secret:
- It is required and must contain
usernameandpasswordfields. - It must be referenced by the
spec.webLogicCredentialsSecretfield in your Domain resource YAML file. For complete details about theDomainresource, see the Domain resource reference . - It also must be referenced by macros in the
domainInfo.AdminUserNameanddomainInfo.AdminPassWordfields in yourmodel.10.yamlfile.
- It is required and must contain
-
The Model WDT runtime encryption secret:
- This is a special secret required by Model in Image.
- It must contain a
passwordfield. - It must be referenced using the
spec.model.runtimeEncryptionSecretfield in your Domain resource YAML file. - It must remain the same for as long as the domain is deployed to Kubernetes but can be changed between deployments.
- It is used to encrypt data as it’s internally passed using log files from the domain’s introspector job and on to its WebLogic Server pods.
-
Deleting and recreating the secrets:
- You must delete a secret before creating it, otherwise the
createcommand will fail if the secret already exists. - This allows you to change the secret when using the
kubectl create secretcommand.
- You must delete a secret before creating it, otherwise the
-
You name and label secrets using their associated
domainUIDfor two reasons:- To make it obvious which secrets belong to which domains.
- To make it easier to clean up a domain. Typical cleanup scripts use the
weblogic.domainUIDlabel as a convenience for finding all resources associated with a domain.
Now, you can verify the secrets with command:
The output looks similar to the following content.
Domain resource
Now, you create a domain YAML file. Think of the domain YAML file as the way to configure some aspects of your WebLogic domain using Kubernetes. The operator uses the Kubernetes “custom resource” feature to define a Kubernetes resource type called Domain. For more on the Domain Kubernetes resource, see
Domain Resource
. For more on custom resources see
the Kubernetes documentation
.
We provide a script at $BASE_DIR/sample-scripts/create-weblogic-domain-on-azure-kubernetes-service/create-domain-on-aks-mii-generate-yaml.sh to generate a domain resource description.
Run the following command to generate resource files.
After running above commands, you will get three files: mii-initial.yaml, admin-lb.yaml and cluster-lb.yaml.
Run the following command to create the domain custom resource:
Successful output will look like:
Verify the WebLogic Server pods are all running:
Output will look similar to the following.
When the system stabilizes with the following state, it is safe to proceed.
It may take you up to 10 minutes to deploy all pods, please wait and make sure everything is ready.
If the system does not reach this state, troubleshoot and resolve the problem before continuing. See Troubleshooting for hints.
Invoke the web application
Create Azure load balancer
Create an Azure public standard load balancer to access the WebLogic Server Administration Console and applications deployed to the cluster.
Use the file admin-lb.yaml to create a load balancer service for the Administration Server. If you are choosing not to use the predefined YAML file and instead created a new one with customized values, then substitute the following content with your domain values.
Use the file cluster-lb.yaml to create a load balancer service for the managed servers. If you are choosing not to use the predefined YAML file and instead created new one with customized values, then substitute the following content with your domain values.
Create the load balancer services using the following commands:
Successful output will look like:
Successful output will look like:
Get the external IP addresses of the Administration Server and cluster load balancers (please wait for the external IP addresses to be assigned):
Successful output will look like:
In the example, the URL to access the Administration Server is: http://52.191.234.149:7001/console.
The expected username and password must match the values that you chose during the
Kubernetes Secrets for WebLogic
step.
IMPORTANT: You must ensure that any Network Security Group rules that govern access to the console allow inbound traffic on port 7001.
If the WLS Administration Console is still not available, use kubectl describe domain to check domain status.
Make sure the status of cluster-1 is ServersReady and Available.
Access the application
Access the Administration Console using the admin load balancer IP address.
Access the sample application using the cluster load balancer IP address.
Successful output will look like:
Rolling updates
Naturally, you will want to deploy newer versions of the EAR application, located in the WDT archive ZIP file at wlsdeploy/applications/myapp-v1. To learn how to do this, follow the steps in
Update 3
.
Database connection
For guidance on how to connect a database to your AKS with WebLogic Server application, see Deploy a Java application with WebLogic Server on an Azure Kubernetes Service (AKS) cluster .
Clean up resources
Run the following commands to clean up resources.
Troubleshooting
For troubleshooting advice, see Troubleshooting .