Decision Management (ODM, ADS)

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CP4BA ODM topologies on OpenShift

By Pierre-Andre Paumelle posted Fri June 24, 2022 06:15 AM

  

Please find a PDF version of this article available here 

Introduction

Operational Decision Manager (ODM) empowers business users and developers to collaborate when they automate an organization’s business policies. ODM automates the decision-making process and governs future policy updates. Execution of the business rules (decision services at runtime) can scale out in clusters of servers running on bare metal, virtual machines, or containers.
In this article we will focus on OpenShift.
These topologies were tested on CP4BA 21.0.3 and 22.0.1

Components and Environments

The main components of ODM in a topology are: 
  • Decision Server console to manage the runtimes
  • Decision Server runtime to execute the decisions services
  • Decision Center to author the decisions services
  • Decision Runner (non production) to execute tests and simulations on decisions
The environments are:
  • Authoring and Unit testing
    •  Decision Center and Decision Runner and Decision Server Console
  • Sandbox runtime testing
    • Decision Server Console and a Decision Server Runtime
  • Pre-prod for runtime to testing the scalability 
    • Decision Server Console and Decision Server Runtimes
  • Production for runtime independent configuration
    • Decision Server Console and Decision Server Runtimes
  • Migration and Upgrade testing (a Bronze Topology)
    • Decision Center, Decision Runner, Decision Server Console and 2 Decision Server Runtimes

ODM topology types

We have three topologies. The names bronze, silver, and gold come about because performance studies show that the scalability depends on the topology. Gold demonstrates better performance than silver, and silver demonstrates better performance than bronze.
  • Bronze topology
    • For prototypes or applications with low production constraints
  • Silver topology
    • For applications with medium production constraints 
  • Gold topology 
    • For applications with high production constraints

Bronze Topology

Bronze topology is the default installation.
All the components are installed in a single namespace.

Boxes represent pods. Decision Center is scaled up to
two pods for HA.
  • Advantages of the Bronze topology

    • Easy to install (Default installation)
    • Tshirt sizing available   
    • HA is supported – multi zone could help
    • External database
    • Disadvantages of the Bronze topology

      • No separation of Dev and production
      • Tests of Migration or update should be done on another cluster
      • DR is not supported
      • No Pre-Prod tests
      • Only Decision Runner tests are possible
    A Bronze topology is for prototypes or applications with low production constraints
     

    Silver topology

    Silver topology makes use of several namespaces in a single cluster.
    Silver topology is multi- namespace, which uses separate routes per namespace.

    Minimum Silver topology without Pre-Prod

    Full silver configuration with Pre-prod and 2 sandboxes

    • Advantages of the Silver topology

      • HA is supported – multi zone could help
      • Pre-Prod test available
      • One Decision Center to govern all Decision Servers
      • Sand Box for developers available
      • External database
    • Warnings of the Silver Topology

      • All Environments are using the same IAM for Authentication
      • Minimum of two namespaces to install (Role and certificate should be tuned)
      • Separation of Dev and production is better than the Bronze Topology
        • But Tests could impact Production performance

    • Disadvantages of the Silver Topology

      • Tests of Migration or update should be done on another cluster
      • DR is not supported (need another cluster)
    The Silver topology is for applications with medium production constraints

    Gold topology

    Multi cluster to get a production authoring separation
    The authentication is separated
    The resources for production are dedicated (cpu/disk/memory/network)
    Pre-Prod and sandboxes could be separated

    Minimum gold topology No Pre-Prod and a single sandbox

    Gold Topology with two sandboxes and a pre-prod

    Gold topology with specialized productions.

    You have 2 Production namespace to make sure that  rulesets are not impacted by others. So, the SLA of these rulesets are guaranteed.
    • Warnings of the Gold topology

      • Complex to install
        • Role and certificate should be tuned
    • Advantages of the Gold topology

      • Complete separation of Dev and production
        • Resources (CPU/Memory/Disks/databases)
        • Authentication coming from separate IAM
      • Migration test could be done step by steps
      • HA is supported – multi zone could help
      • DR could be supported by adding clusters in multi-geo ( several Datacenters)
      • Pre-Prod test available
      • Decision Runner tests are possible
      • Sand Box for developers available
      • External database
    Gold topology is for application with high production constraints

    ODM Topology options

    The best topology for you depends on your needs and choices.
    To choose the option best suited for your needs answer the following questions:
      • Do you need a separation per domain or Business unit? 
        • For Authoring?
        • For Production?
      • Do you need multi-geo for Disaster Recovery or performance? 
        • Multi-geo for Authoring is on an Active/passive mode only
      • Do you need a specific access management per domain or Business unit?
      • Ruleset Deployment mode
        • With Decision Center
        • With CI/CD
          • With CI/CD the artifacts can be stored in a repository and redeployed with the exact same version.


    Installation guides

    All these topologies were tested and we are writing installation guides based on these tests.

    Bronze topology installation guide 21.0.3 version
    Silver topology installation guide 21.0.3 version 


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