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Release J: Simple rApp using Hello World Microservice

Release J: Simple rApp using Hello World Microservice

Owned by Ambrish Singh
Last updated: Feb 02, 2024


Introduction

Welcome to the user guide on packaging the Helm chart for the hello-world microservice into a CSAR (Cloud Service Archive) with Automation Composition Management (ACM) definitions. This guide is designed to help you seamlessly integrate your microservices into an ACM-enabled Kubernetes environment, enabling efficient orchestration and management.

Purpose

As organizations embrace microservices architecture, the need for effective orchestration and automation becomes critical. Automation Composition Management (ACM) provides a solution by allowing users to define, deploy, and manage complex microservice compositions seamlessly.

This documentation focuses on packaging a Helm chart, which encapsulates the hello-world microservice, into a CSAR. The CSAR includes not only the Helm chart for deployment but also ACM definitions that specify how the microservice should be orchestrated and interact with other components in your Kubernetes environment. 

Prerequisites

Before you proceed, please ensure that the following prerequisites are met:

  • ACM components including acm-runtime and required participants (Kubernetes in this case) are deployed in docker or Kubernetes environment.
  • Kubernetes and Helm are installed.
  • Chartmuseum server is installed to host the hello-world microservice helm chart.

Now, let's dive into the step-by-step process of packaging your Helm chart into a CSAR with ACM definitions for a seamless integration with ACM in your Kubernetes environment.

Overview

In this section, we provide a high-level overview of the process of packaging the Helm chart for the hello-world microservice into an rApp Package. This packaging process enables you to create a Cloud Service Archive (CSAR) that not only includes the Helm chart for deployment but also integrates Automation Composition Management (ACM) definitions, TOSCA metadata, and essential metadata files. This integration ensures seamless orchestration and management of your microservices within a Kubernetes environment.

Components

  • Helm Chart - The Helm chart encapsulates the hello-world microservice along with its configurations and dependencies. It serves as the deployment package for your microservice.
  • ACM Compositions - ACM compositions define how the microservice components interact within the Kubernetes environment. These compositions provide a blueprint for orchestrating complex scenarios and enable the dynamic configuration of microservice deployments.
  • ACM Instance Files - Instance files specify the configurations and details for the deployment of ACM compositions. Each instance file represents a unique deployment scenario or configuration set.
  • TOSCA Metadata - The TOSCA Metadata file specifies essential metadata about the CSAR, including version information and the entry definition file. It plays a crucial role in defining the structure and versioning of the CSAR.
  • Metadata File - The Metadata File contains metadata specific to the application service descriptor (ASD). It includes information such as the application name, provider, release date/time, and entry definition type. It also lists the sources for the CSAR, including TOSCA files and ACM definition files.

Relationship with ACM and Kubernetes

The rApp Package combines the strengths of Helm for microservice deployment with the orchestration capabilities of ACM in a Kubernetes environment. ACM ensures that your microservices are deployed and configured according to defined compositions, allowing for flexibility and adaptability in complex scenarios.

Benefits

  • Seamless Integration - The rApp Package seamlessly integrates Helm, ACM, and Kubernetes, providing a unified approach to microservice orchestration.
  • Dynamic Configuration - ACM compositions allow for dynamic configuration changes, enabling the adaptation of your microservices to different deployment scenarios.
  • Efficient Management - The combination of Helm and ACM streamlines the deployment and management of microservices, reducing complexity and enhancing operational efficiency.


Now, let's proceed with the step-by-step guide to package your Helm chart into an rApp Package with ACM definitions for deployment in your Kubernetes environment.

rApp Generator: Creating a CSAR Package

Overview

The rApp Generator simplifies the process of creating a Cloud Service Archive (CSAR) package, including Automation Composition Management (ACM) definitions, for your microservices. This guide outlines the directory structure, contents, and the steps involved in using the `generate.sh` script to generate a CSAR package.

Directory Structure

rapp-hello-world

|-- definitions

    -- asd.yaml

    -- asd_types.yaml

|-- files

      -- Acm

          -- definition

               -- compositions.json

          -- instances

               -- k8s-instance.json

|-- TOSCA-Metadata

      -- TOSCA.meta

|-- asd.mf

|-- generate.sh

|-- generate.bat


ACM Definitions and Types (asd.yaml and asd_types.yaml)

TOSCA is a standard for describing the topology and orchestration of cloud applications. The asd.yaml and asd_types.yaml files conform to the TOSCA specification and defining the application service descriptor (ASD) and related types. They describe the structure and properties of the application service, its components, and configurations.

ACM Compositions (compositions.json)

The file containing ACM compositions must be named compositions.json. This JSON file defines the ACM compositions for the rApp. It includes data types, node types, and a topology template specifying the structure of the compositions. ACM compositions define how the application components interact. They specify the structure of the automation composition and the types of components involved.

ACM Instance (k8s-instance.json)

This JSON file represents an instance of the ACM composition. It specifies the name, version, and properties of the instance, including the elements involved (e.g., K8S microservice) and their configurations. In this case, it includes information about the K8S microservice. While there is no strict naming convention for instance files, it is recommended to use descriptive names that reflect the purpose or content of the instance.

TOSCA Metadata (TOSCA.meta)

This file provides metadata about the CSAR. It includes the CSAR version, TOSCA meta-file version, the entry definition file, and ETSI-specific information.

Metadata File (asd.mf)

This file contains metadata for the application service descriptor (ASD). It includes information such as the application name, provider, release date/time, and entry definition type. It also lists the sources for the CSAR, including TOSCA files and ACM definition files.


CSAR Generation Process

Prepare your rApp Resources:
   - Organize ASD definitions, ACM compositions, instance files, and TOSCA Metadata in the designated directory structure.

Run the `generate.sh` Script:
   - Execute the `generate.sh` script, providing the rApp resource folder name as a parameter.


          ./generate.sh rapp-hello-world     

Verification:
   - Check for any error messages during the CSAR generation process.
   - Verify that the CSAR file (`rapp-hello-world.csar`) is generated in the same directory.

Result:
   - Once the process is complete, the script will indicate that the rApp package has been generated successfully.

rApp package rapp-hello-world.csar generated.


ACM Compositions for Kubernetes Deployment

To construct a seamless ACM topology for Kubernetes (k8s), it is imperative to adhere to a comprehensive TOSCA definition that encapsulates essential elements.

ACM Definition Overview

The following code snippets provide a foundational framework, encompassing data types, node types, and specific configurations necessary for a robust ACM deployment:

{
  "tosca_definitions_version": "tosca_simple_yaml_1_3",
  "data_types": {
    "onap.datatypes.ToscaConceptIdentifier": {
      "derived_from": "tosca.datatypes.Root",
      "properties": {
        "name": {
          "type": "string",
          "required": true
        },
        "version": {
          "type": "string",
          "required": true
        }
      }
    }
  },
  "node_types": {
    "org.onap.policy.clamp.acm.Participant": {
      "version": "1.0.1",
      "derived_from": "tosca.nodetypes.Root",
      "properties": {
        "provider": {
          "type": "string",
          "required": false
        }
      }
    },
    "org.onap.policy.clamp.acm.AutomationCompositionElement": {
      "version": "1.0.1",
      "derived_from": "tosca.nodetypes.Root",
      "properties": {
        "provider": {
          "type": "string",
          "required": false
        },
        "participantType": {
          "type": "onap.datatypes.ToscaConceptIdentifier",
          "required": true
        },
        "startPhase": {
          "type": "integer",
          "required": false,
          "constraints": [
            {
              "greater-or-equal": 0
            }
          ],
          "metadata": {
            "common": true
          },
          "description": "A value indicating the start phase in which this automation composition element will be started, the first start phase is zero. Automation Composition Elements are started in their start_phase order and stopped in reverse start phase order. Automation Composition Elements with the same start phase are started and stopped simultaneously"
        },
        "passiveToRunningTimeout": {
          "type": "integer",
          "required": false,
          "constraints": [
            {
              "greater_or_equal": 0
            }
          ],
          "default": 60,
          "metadata": {
            "common": true
          },
          "description": "The maximum time in seconds to wait for a state chage from passive to running"
        },
        "runningToPassiveTimeout": {
          "type": "integer",
          "required": false,
          "constraints": [
            {
              "greater_or_equal": 0
            }
          ],
          "default": 60,
          "metadata": {
            "common": true
          },
          "description": "The maximum time in seconds to wait for a state chage from running to passive"
        },
        "passiveToUninitializedTimeout": {
          "type": "integer",
          "required": false,
          "constraints": [
            {
              "greater_or_equal": 0
            }
          ],
          "default": 60,
          "metadata": {
            "common": true
          },
          "description": "The maximum time in seconds to wait for a state chage from passive to uninitialized"
        }
      }
    },
    "org.onap.policy.clamp.acm.AutomationComposition": {
      "version": "1.0.1",
      "derived_from": "tosca.nodetypes.Root",
      "properties": {
        "provider": {
          "type": "string",
          "required": false,
          "metadata": {
            "common": true
          }
        },
        "elements": {
          "type": "list",
          "required": true,
          "metadata": {
            "common": true
          },
          "entry_schema": {
            "type": "onap.datatypes.ToscaConceptIdentifier"
          }
        }
      }
    },
    "org.onap.policy.clamp.acm.K8SMicroserviceAutomationCompositionElement": {
      "version": "1.0.0",
      "derived_from": "org.onap.policy.clamp.acm.AutomationCompositionElement",
      "properties": {
        "chart": {
          "type": "string",
          "required": true
        },
        "configs": {
          "type": "list",
          "required": false
        },
        "requirements": {
          "type": "string",
          "required": false
        },
        "templates": {
          "type": "list",
          "required": false,
          "entry_schema": null
        },
        "values": {
          "type": "string",
          "required": true
        }
      }
    }
  },
  "topology_template": {
    "node_templates": {
      "org.onap.k8s.acm.K8SAutomationCompositionParticipant": {
        "version": "2.3.4",
        "type": "org.onap.policy.clamp.acm.Participant",
        "type_version": "1.0.1",
        "description": "Participant for K8S",
        "properties": {
          "provider": "ONAP"
        }
      },
      "onap.policy.clamp.ac.element.K8S_StarterAutomationCompositionElement": {
        "version": "1.2.3",
        "type": "org.onap.policy.clamp.acm.K8SMicroserviceAutomationCompositionElement",
        "type_version": "1.0.0",
        "description": "Automation composition element for the K8S microservice for AC Element Starter",
        "properties": {
          "provider": "ONAP",
          "startPhase": 0,
          "uninitializedToPassiveTimeout": 300,
          "podStatusCheckInterval": 30
        }
      },
      "onap.policy.clamp.ac.element.AutomationCompositionDefinition": {
        "version": "1.2.3",
        "type": "org.onap.policy.clamp.acm.AutomationComposition",
        "type_version": "1.0.1",
        "description": "Automation composition for rapp deployment",
        "properties": {
          "provider": "ONAP",
          "elements": [
            {
              "name": "onap.policy.clamp.ac.element.K8S_StarterAutomationCompositionElement",
              "version": "1.2.3"
            }
          ]
        }
      }
    }
  }
}


The provided ACM TOSCA definition includes key elements necessary for defining an ACM topology for Kubernetes (k8s). However, to avoid errors, ensure that the definitions are complete and correctly referenced.

Required Definitions

The ACM TOSCA definition includes key data types and node types such as ToscaConceptIdentifier, Participant, AutomationCompositionElement, AutomationComposition, and K8SMicroserviceAutomationCompositionElement. These definitions represent building blocks for ACM topologies, specifically for Kubernetes deployments.

  1. ToscaConceptIdentifier:

    • Properties: name and version.

  2. Participant:

    • Properties: provider (optional).

  3. AutomationCompositionElement:

    • Properties: provider (optional), participantType (referencing ToscaConceptIdentifier), and additional timing-related properties.

  4. AutomationComposition:

    • Properties: provider (optional), elements (list of ToscaConceptIdentifier).

  5. K8SMicroserviceAutomationCompositionElement:

    • Derived from AutomationCompositionElement.
    • Properties: chart, configs, requirements, templates, and values.

  6. Topology Template:

    • Node Templates for relevant ACM entities.

Reference Flow

  1. Participant Definition:

    • Ensure that Participant definitions are referenced correctly in node templates.

  2. Automation Composition Element:

    • Use AutomationCompositionElement in the node templates and ensure correct referencing of the ToscaConceptIdentifier for participantType.

  3. Automation Composition:

    • Reference the correct AutomationCompositionElement in the AutomationComposition definition.

  4. K8S Microservice Automation Composition Element:

    • Ensure that the K8SMicroserviceAutomationCompositionElement is used for Kubernetes-specific compositions.

  5. Top-Level Node Templates:

    • Node templates like K8SAutomationCompositionParticipant and others should reference the appropriate definitions.

Errors and Debugging

When utilizing the provided ACM TOSCA definition for Kubernetes (k8s), it is essential to include all key elements to define the ACM topology accurately. Failure to incorporate required definitions may lead to errors during the deployment process. Common indicators of missing components include repeated YAML separator lines (---) and unexpected empty sections. To illustrate, if the definitions for org.onap.policy.clamp.acm.AutomationCompositionElement or org.onap.policy.clamp.acm.Participant are absent, errors such as NullPointerException or unexpected behavior during deployment might occur. Therefore, it is crucial to thoroughly review and complete the TOSCA definition, ensuring all necessary components are correctly specified to avoid potential issues.

  • If errors occur, check the console logs for NullPointerExceptions or missing property issues.
  • The error may indicate missing references or incorrect properties in the TOSCA definitions.
  • Ensure that all referenced elements (e.g., ToscaConceptIdentifier, Participant, etc.) are correctly defined and referenced.

For instance, if the definitions for org.onap.policy.clamp.acm.AutomationCompositionElement or org.onap.policy.clamp.acm.Participant are absent, errors such as NullPointerException or unexpected behavior during deployment might occur. 

java.lang.NullPointerException: Cannot invoke "org.onap.policy.models.tosca.authorative.concepts.ToscaNodeTemplate.getProperties()" because the return value of "java.util.Map.get(Object)" is null
        at com.oransc.rappmanager.models.AcmInterceptor.injectToscaServiceTemplate(AcmInterceptor.java:57) ~[rapp-manager-models-0.1.0-SNAPSHOT.jar!/:0.1.0-SNAPSHOT]
        at com.oransc.rappmanager.dme.service.DmeAcmInterceptor.injectToscaServiceTemplate(DmeAcmInterceptor.java:68) ~[rapp-manager-dme-0.1.0-SNAPSHOT.jar!/:0.1.0-SNAPSHOT]
        at com.oransc.rappmanager.acm.service.AcmDeployer.createComposition(AcmDeployer.java:85) ~[rapp-manager-acm-0.1.0-SNAPSHOT.jar!/:0.1.0-SNAPSHOT]
        at com.oransc.rappmanager.acm.service.AcmDeployer.primeRapp(AcmDeployer.java:187) ~[rapp-manager-acm-0.1.0-SNAPSHOT.jar!/:0.1.0-SNAPSHOT]
        at com.oransc.rappmanager.service.RappService.lambda$primeRapp$0(RappService.java:53) ~[!/:0.1.0-SNAPSHOT]
        at java.base/java.util.stream.MatchOps$1MatchSink.accept(Unknown Source) ~[na:na]
        at java.base/java.util.ArrayList$ArrayListSpliterator.tryAdvance(Unknown Source) ~[na:na]
        at java.base/java.util.stream.ReferencePipeline.forEachWithCancel(Unknown Source) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.copyIntoWithCancel(Unknown Source) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source) ~[na:na]
        at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source) ~[na:na]
        at java.base/java.util.stream.MatchOps$MatchTask.doLeaf(Unknown Source) ~[na:na]
        at java.base/java.util.stream.MatchOps$MatchTask.doLeaf(Unknown Source) ~[na:na]
        at java.base/java.util.stream.AbstractShortCircuitTask.compute(Unknown Source) ~[na:na]
        at java.base/java.util.concurrent.CountedCompleter.exec(Unknown Source) ~[na:na]
        at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source) ~[na:na]
        at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source) ~[na:na]
        at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source) ~[na:na]
        at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) ~[na:na]
        at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) ~[na:na] 



java.lang.NullPointerException: Cannot invoke "org.onap.policy.clamp.models.acm.concepts.AutomationComposition.getElements()" because "automationComposition" is null
        at com.oransc.rappmanager.models.AcmInterceptor.injectAutomationComposition(AcmInterceptor.java:84) ~[rapp-manager-models-0.0.1.jar!/:0.0.1]
        at com.oransc.rappmanager.acm.service.AcmDeployer.deployRappInstance(AcmDeployer.java:141) ~[rapp-manager-acm-0.0.1.jar!/:0.0.1]
        at com.oransc.rappmanager.service.RappService.deployRappInstance(RappService.java:106) ~[!/:0.0.1]
        at com.oransc.rappmanager.rest.RappInstanceController.lambda$deployRappInstance$10(RappInstanceController.java:95) ~[!/:0.0.1]
        at java.base/java.util.Optional.map(Unknown Source) ~[na:na]
        at com.oransc.rappmanager.rest.RappInstanceController.lambda$deployRappInstance$12(RappInstanceController.java:95) ~[!/:0.0.1]
        at java.base/java.util.Optional.map(Unknown Source) ~[na:na]
        at com.oransc.rappmanager.rest.RappInstanceController.deployRappInstance(RappInstanceController.java:93) ~[!/:0.0.1]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:na]
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:na]


ACM Instance for Kubernetes Deployment

The following example showcases an ACM instance designed for Kubernetes deployment:

{
  "name": "DemoInstance0",
  "version": "1.0.1",
  "compositionId": "COMPOSITIONID",
  "description": "Demo automation composition instance 0",
  "elements": {
    "709c62b3-8918-41b9-a747-d21eb79c6c21": {
      "id": "709c62b3-8918-41b9-a747-d21eb79c6c21",
      "definition": {
        "name": "onap.policy.clamp.ac.element.K8S_StarterAutomationCompositionElement",
        "version": "1.2.3"
      },
      "description": "Starter Automation Composition Element for the Hello World",
      "properties": {
        "chart": {
          "chartId": {
            "name": "hello-world-chart",
            "version": "0.1.0"
          },
          "namespace": "nonrtric",
          "releaseName": "hello-world-chart",
          "podName": "hello-world-chart",
          "repository": {
            "repoName": "local",
            "address": "http://10.101.1.90:8879/charts"
          }
        }
      }
    }
  }
}


In this instance, "DemoInstance0" is specified with a version of "1.0.1," associated with a composition ID "COMPOSITIONID," and described as a demo automation composition. The instance contains a single element with the ID "709c62b3-8918-41b9-a747-d21eb79c6c21." This element is defined as the "K8S_StarterAutomationCompositionElement" with version "1.2.3." It represents the starter automation composition element for the Hello World service.

The element's properties include a reference to the Helm chart named "hello-world-chart" with version "0.1.0." The chart is intended for deployment in the "nonrtric" namespace with a release name, pod name, and repository details pointing to the local repository at "http://10.101.1.90:8879/charts."

This structured representation provides a clear overview of the ACM instance designed for deploying the Hello World service on Kubernetes.


SME service exposure for "Hello World" REST endpoints

To expose "Hello World" microservice endpoints through the Service Management and Exposure (SME), you need to create SME configurations and package them within the same rApp package that contains the Kubernetes participant.

SME Configuration Structure

The SME configuration consists of three directories: providers, serviceapis, and invokers, each containing specific JSON files.

providers/provider-function-1.json

{
  "apiProvDomInfo": "Provider domain",
  "apiProvFuncs": [
    {
      "apiProvFuncInfo": "Hello World as APF",
      "apiProvFuncRole": "APF",
      "regInfo": {
        "apiProvPubKey": "APF-PublicKey"
      }
    },
    {
      "apiProvFuncInfo": "Hello World as AEF",
      "apiProvFuncRole": "AEF",
      "regInfo": {
        "apiProvPubKey": "AEF-PublicKey"
      }
    }
  ],
  "regSec": "PSK"
}


serviceapis/api-set-1.json


{
  "apiName": "Hello World API Set 1",
  "description": "Simple Hello World API",
  "aefProfiles": [
    {
      "aefId": "Hello World as AEF",
      "description": "Simple Hello World API",
      "versions": [
        {
          "apiVersion": "v1",
          "resources": [
            {
              "resourceName": "helloworld",
              "commType": "REQUEST_RESPONSE",
              "uri": "/helloworld/v1",
              "operations": [
                "GET"
              ]
            }
          ]
        }
      ],
      "protocol": "HTTP_1_1",
      "securityMethods": [
        "PSK"
      ],
      "interfaceDescriptions": [
        {
          "ipv4Addr": "string",
          "port": 30951,
          "securityMethods": [
            "PKI"
          ]
        },
        {
          "ipv4Addr": "string",
          "port": 30951,
          "securityMethods": [
            "PKI"
          ]
        }
      ]
    }
  ]
}


invokers/invoker-app1.json


[
  {
    "apiInvokerInformation": "Invoker App 1",
    "apiList": [
      {}
    ],
    "notificationDestination": "http://invoker-app1:8086/callback",
    "onboardingInformation": {
      "apiInvokerPublicKey": "{PUBLIC_KEY_INVOKER_1}",
      "apiInvokerCertificate": "apiInvokerCertificate"
    },
    "requestTestNotification": true
  }
]


Querying Available APIs

After configuring SME, you can query the available APIs exposed by SME. Replace <NAMESPACE> with your Kubernetes namespace.


CAPIF_HOST=http://$(kubectl get service capifcore -n nonrtric -o jsonpath='{.spec.clusterIP}'):8090

curl -sS --location "$CAPIF_HOST/service-apis/v1/allServiceAPIs?api-invoker-id=api_invoker_id_Invoker_App_1" --header 'Accept: application/json' | jq

This command queries the SME to retrieve information about all available service APIs for the specified API invoker.

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