feat(self-managed): OpenShift ROSA instructions and rework of the ref…

…erence arch for OpenShift (#4734)

docs/self-managed/setup/deploy/amazon/amazon-eks/eks-helm.md

@@ -4,6 +4,8 @@ title: "Install Camunda 8 on an EKS cluster"
 description: "Set up the Camunda 8 environment with Helm and an optional Ingress setup on Amazon EKS."
 ---
 
+<!-- (!) Note: Please ensure that this guide maintains a consistent structure and presentation style throughout, as with docs/self-managed/setup/deploy/openshift/terraform-setup.md. The user should have a similar experience when reading both guides. -->
+
 import Tabs from "@theme/Tabs";
 import TabItem from "@theme/TabItem";
 
@@ -30,6 +32,7 @@ Multi-tenancy is disabled by default and is not covered further in this guide. I
 :::caution Optimize compatibility with OpenSearch
 
 **Migration:** The migration step will be disabled during the installation. For more information, refer to [using Amazon OpenSearch Service](/self-managed/setup/guides/using-existing-opensearch.md).
+
 :::
 
 ## Architecture
@@ -427,7 +430,6 @@ https://github.com/camunda/camunda-tf-eks-module/blob/main/examples/camunda-8.7/
 
 Use these environment variables in the `kubectl` command to create the secret.
 
-- The values for `postgres-password` and `password` are not required if you are using an external database. If you choose not to use an external database, you must provide those values.
 - The `smtp-password` should be replaced with the appropriate external value ([see how it's used by Web Modeler](/self-managed/modeler/web-modeler/configuration/configuration.md#smtp--email)).
 
 ```bash reference
@@ -569,7 +571,7 @@ Below is a summary of the necessary instructions:
 1. Open Identity in your browser at `https://${DOMAIN_NAME}/identity`. You will be redirected to Keycloak and prompted to log in with a username and password.
 2. Use `demo` as both the username and password.
 3. Select **Add application** and select **M2M** as the type. Assign a name like "test."
-4. Select the newly created application. Then, select **Access to APIs > Assign permissions**, and select the **Zeebe API** with "write" permission.
+4. Select the newly created application. Then, select **Access to APIs > Assign permissions**, and select the **Core API** with "read" and "write" permission.
 5. Retrieve the `client-id` and `client-secret` values from the application details
 
 ```shell
@@ -591,7 +593,7 @@ kubectl port-forward services/camunda-keycloak 18080:80 --namespace camunda
 1. Open Identity in your browser at `http://localhost:8080`. You will be redirected to Keycloak and prompted to log in with a username and password.
 2. Use `demo` as both the username and password.
 3. Select **Add application** and select **M2M** as the type. Assign a name like "test."
-4. Select the newly created application. Then, select **Access to APIs > Assign permissions**, and select the **Zeebe API** with "write" permission.
+4. Select the newly created application. Then, select **Access to APIs > Assign permissions**, and select the **Core API** with "read" and "write" permission.
 5. Retrieve the `client-id` and `client-secret` values from the application details
 
 ```shell

docs/self-managed/setup/deploy/amazon/amazon-eks/terraform-setup.md

@@ -96,25 +96,25 @@ Advanced users may want to handle this part differently and use a different back
 #### Set up AWS authentication
 
 The [AWS Terraform provider](https://registry.terraform.io/providers/hashicorp/aws/latest/docs) is required to create resources in AWS. Before you can use the provider, you must authenticate it using your AWS credentials.
-You can further change the region and other preferences and explore different [authentication](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#authentication-and-configuration) methods.
 
-We recommend using the [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html). If you have configured your AWS CLI, Terraform will automatically detect and use those credentials.
+:::caution Ownership of the created resources
 
-To configure the AWS CLI:
+A user who creates resources in AWS will always retain administrative access to those resources, including any Kubernetes clusters created. It is recommended to create a dedicated [AWS IAM user](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_users.html) for Terraform purposes, ensuring that the resources are managed and owned by that user.
 
-```bash
-aws configure
-```
+:::
 
-Enter your `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY`, region, and output format. These can be retrieved from the [AWS Console](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html).
+You can further change the region and other preferences and explore different [authentication](https://registry.terraform.io/providers/hashicorp/aws/latest/docs#authentication-and-configuration) methods:
 
-:::caution Ownership of the created resources
+- For development or testing purposes you can use the [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html). If you have configured your AWS CLI, Terraform will automatically detect and use those credentials.
+  To configure the AWS CLI:
 
-A user who creates resources in AWS will always retain administrative access to those resources, including any Kubernetes clusters created. It is recommended to create a dedicated [AWS IAM user](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_users.html) for Terraform purposes, ensuring that the resources are managed and owned by that user.
+  ```bash
+  aws configure
+  ```
 
-[Create access keys](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html) for the new IAM user via the console and export them as `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY` variables to use with the AWS CLI and `eksctl`
+  Enter your `AWS_ACCESS_KEY_ID`, `AWS_SECRET_ACCESS_KEY`, region, and output format. These can be retrieved from the [AWS Console](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html).
 
-:::
+- For production environments, we recommend the use of a dedicated IAM user. Create [access keys](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html) for the new IAM user via the console, and export them as `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`.
 
 #### Create an S3 bucket for Terraform state management