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1. Introduction

To fulfill various usage needs it is important that all CPS applications can be configured when they are deployed without requiring any change in the application artifacts (docker images).

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• Custom CPS properties specific to the application
• Spring Boot defined properties: https://docs.spring.io/spring-boot/docs/current/reference/html/application-properties.html#appendix.application-properties

2. Current Implementation (Jakarta)

CPS configuration properties are implemented at different level

2.1.

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Application Level

Following are the properties that are should be defined at application level in the default application.yml file from the application repository:

• Application custom properties for any value that should not be hard-coded in the application code source. A default value is provided in the properties file. When deploying the application any user has the option to use the default value provided by the application or change the value to run with a different one.
• Spring Boot defined properties that need to be set for the application (either because Spring default value does not fit or is not set).

Detailed configuration:

• All application configuration
• Database connectivity configuration
• Kafka connectivity configuration at application level is a Plain Text basic configuration ready to be used and tested easily on a local dev environment.

For example , see properties file for CPS applicationCore:

• https://github.com/onap/cps/blob/jakarta/cps-application/src/main/resources/application.yml

2.2. Helm Chart Level

When CPS applications are deployed in a Kubernetes environment, they are configured to run with a specific helm Spring profile specified by SPRING_PROFILES_ACTIVE environment variable. For example, see CPS Core:

• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/templates/deployment.yaml#L92
• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/values.yaml#L177

Then, OOM chart application-helm.yml is mounted in the application container to provide helm  profile configuration values. For example see CPS Core:

• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/templates/deployment.yaml#L102

OOM chart application-helm.yml should contain following properties:

• All properties already defined in application application.yaml file but need to be changed (overridden) to provide another default value for Kubernetes deployment and runtime.
• Any Spring Boot defined property that is not specified in application aplication.yml file but need to be specified (set) for Kubernetes deployment and runtime.

Any value property set in application application.yaml file and not re-defined in Helm profile is still loaded and kept unchanged. There is no need to duplicate the properties in Helm profile.

Detailed configuration:

• Database connectivity configuration for with Helm defined database service values
• Kafka connectivity configuration if ONAP Strimzy Kafka is used

For example see CPS Core:

• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/resources/config/application-helm.yml

2.3. Helm Values Level

Finally, still when deploying CPS application in a specific user environment, the user can to provide its own custom helm overrides values to customize the application in any specific target environment.

When doing this the user is still able to provide and set any additional application property he needs. Such properties are added under following properties paths:

• config.additionaProperties.* for any additional application or Spring property to be added
• config.eventPublisher.* for Kafka custom configuration properties (if ONAP Strimzi Kafka is not used)

These properties paths are automatically added to the Spring Helm profile by following Helm templating:

• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/resources/config/application-helm.yml#L66
• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/resources/config/application-helm.yml#L62

Detailed configuration:

• Any application configuration (custom application or default Spring Boot to be overridden or added)
• Kafka connectivity configuration if Kafka server is provisioned independently from ONAP

For example, see CPS Core:

• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/values.yaml#L193
• https://github.com/onap/oom/blob/jakarta/kubernetes/cps/components/cps-core/values.yaml#L199

The values above are specified in the OOM CPS values file, but the user is still able to also create and provide its own overrides values file to be used when deploying.

3. Improvements & Cleanup

Jira for below work:  

3.1. Remove Unused Properties

At application level, properties that are not used can be removed:

• spring.liquibase.labels ?
• Any other ?

3.2. Remove Duplicated Properties

At Helm chart level, considering that Helm profile is an add-on to the default profile, useless duplicates can be removed:

• spring.liquibase.* 
• spring.kafka.producer.client-id
• security.* 
• logging.*  (and also remove logging.*  values from values files if not used anywhere else)
• dmi.* 

3.3. Rename path for properties dynamically redefined (optional)

4. Example

Considering following configuration files for default application properties, helm profile properties and helm overrides values:

my-cps:
  property-1: my-value-1
  property-2: my-value-2
  property-3: my-value-3

spring:
  application:
    name: my-application-name
  main:
    banner-mode: console

my-cps:
  property-2: my-other-value-2

spring:
  main:
    banner-mode: off
    log-startup-info: false

config:
  overrides:
    my-cps.property-3: my-other-value-3
    spring.datasource.hikari.maximum-pool-size: 20

Then resulting configuration are:

• Default application running:

my-cps:
  property-1: my-value-1
  property-2: my-value-2
  property-3: my-value-3

spring:
  application:
    name: my-application-name
  main:
    banner-mode: console
    log-startup-info: true				# Default Spring value
  datasource:
    hikari:
      maximum-pool-size: 10				# Default Spring value

• K8s helm deployment without overrides provided:

my-cps:
  property-1: my-value-1
  property-2: my-other-value-2			# From Spring Helm profile
  property-3: my-value-3

spring:
  application:
    name: my-application-name
  main:
    banner-mode: off					# From Spring Helm profile
    log-startup-info: false				# From Spring Helm profile
  datasource:
    hikari:
      maximum-pool-size: 10				# Default Spring value

• K8s helm deployment with overrides provided:

my-cps:
  property-1: my-value-1
  property-2: my-other-value-2			# From Spring Helm profile
  property-3: my-other-value-3			# From Helm overrides

spring:
  application:
    name: my-application-name
  main:
    banner-mode: off				 	# From Spring Helm profile
    log-startup-info: false				# From Spring Helm profile
  datasource:
    hikari:
      maximum-pool-size: 20				# From Helm overrides