Add new idle stop order examples

blue-green-deploy-strategy/blue-green-dependency-aware-idle-stop-order/README.adoc

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+= Dependency-Aware Stop Order in Blue-Green Deployments
+:toc:
+:toclevels: 2
+
+== Overview
+
+This example demonstrates how to use the `bg-dependency-aware-stop-order` parameter together with the `deployed-after` attribute to prevent transient failures during blue-green deployments of MTAs.
+
+In complex application setups, some modules depend on others being continuously available. During the final phase of a blue-green deployment, idle applications are restarted and stopped. If this happens in an incorrect order, dependent modules may temporarily lose access to their dependencies, leading to request failures.
+
+== Scenario
+
+The MTA consists of the following modules:
+
+* `provider-app` – a module that must remain available
+* `consumer-app` – an application module that depends on `provider-app`
+
+The `consumer-app` module communicates with `provider-app` during runtime. If `provider-app` is stopped while `consumer-app` is still running, requests from `consumer-app` to `provider-app` will fail.
+
+== Problem
+
+During a standard blue-green deployment:
+
+. Idle versions of all modules are started.
+. The deployment enters the final (resume) phase.
+. Idle applications are stopped and restarted.
+
+Without dependency-aware ordering, `provider-app-idle` may be stopped while `consumer-app-idle` is still running, causing transient failures due to the temporary unavailability of `provider-app`.
+
+== Solution
+
+Enable dependency-aware stop order using one of the following options:
+
+Set the global boolean parameter bg-dependency-aware-stop-order (default: false) in the deployment descriptor, or enable it at deploy time using the command-line option:
+
+`cf deploy hello.mtar --strategy blue-green --dependency-aware-stop-order`
+
+NOTE: When both are specified, the command-line flag `--dependency-aware-stop-order` takes precedence over the descriptor parameter.
+
+This ensures that during the final phase of the blue-green deployment:
+
+* Dependent modules are stopped first
+* Dependencies remain available
+* Dependencies are restarted before dependent modules are updated and started
+
+
+== Example Deployment
+
+Deploy the application using the blue-green strategy:
+
+[source,bash]
+----
+ cf deploy hello.mtar --strategy blue-green --skip-testing-phase                            
+Deploying multi-target app archive hello.mtar in org ... / space ... as ...
+...
+Operation ID: 42063835-fde4-11f0-b2f9-eeee0a981ee1
+Deploying in org "..." and space "..."
+Detected MTA schema version: "3"
+No deployed MTA detected - this is initial deployment of MTA with ID "hello-world"
+Detected new MTA version: "1.0.0"
+Creating application "provider-app-idle" from MTA module "provider-app"...
+Uploading application "provider-app-idle"...
+Started async upload of application "provider-app-idle"
+Staging application "provider-app-idle"...
+Application "provider-app-idle" staged
+Starting application "provider-app-idle"...
+Application "provider-app-idle" started and available at "..."
+Creating application "consumer-app-idle" from MTA module "consumer-app"...
+Uploading application "consumer-app-idle"...
+Started async upload of application "consumer-app-idle"
+Staging application "consumer-app-idle"...
+Application "consumer-app-idle" staged
+Starting application "consumer-app-idle"...
+Application "consumer-app-idle" started and available at "..."
+----
+
+Resume phase: 
+
+[source,bash]
+----
+Detected new MTA version: "1.0.0"
+Application "consumer-app-idle" stopped
+Updating application "provider-app-idle"...
+Renaming application "provider-app-idle" to "provider-app"...
+Stopping application "provider-app"...
+Starting application "provider-app"...
+Application "provider-app" started and available at "..."
+Updating application "consumer-app-idle"...
+Renaming application "consumer-app-idle" to "consumer-app"...
+Starting application "consumer-app"...
+Application "consumer-app" started and available at "..."
+Skipping deletion of services, because the command line option "--delete-services" is not specified.
+Process finished.
+Use "cf dmol -i 42063835-fde4-11f0-b2f9-eeee0a981ee1" to download the logs of the process.
+----
+
+We can see that with dependency-aware stop order enabled in the resume phase:
+
+* `consumer-app` is stopped before `provider-app`
+* `provider-app` is restarted before `consumer-app` is started again
+
+
+== Notes
+
+* This parameter affects only the final phase of a blue-green deployment.
+* It does not affect the testing phase, during which both live and idle applications run in parallel.
+* The feature is disabled by default and must be explicitly enabled.
+
+For more information, see:
+https://help.sap.com/docs/btp/sap-business-technology-platform/parameters-and-properties#parameters

blue-green-deploy-strategy/blue-green-dependency-aware-idle-stop-order/mta.yaml

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+_schema-version: 3.3.0
+ID: hello-world
+version: 1.0.0
+parameters:
+  bg-dependency-aware-stop-order: true
+
+modules:
+- name: provider-app
+  type: staticfile
+  path: content/hello_world.zip
+  parameters:
+    memory: 64M
+
+- name: consumer-app
+  type: staticfile
+  path: content/hello_world.zip
+  deployed-after:
+      - provider-app
+  parameters:
+    memory: 64M