Blue-green deployments

A blue-green deployment has two separate, but identical, environments where both “old” and “new” versions of an application run simultaneously in production. Blue is the old version, and Green is the new one. Users are migrated to the new application version (Green) after it has been deployed to production.

Using a blue-green deployment increases application availability and reduces deployment risk by simplifying the rollback process if a deployment fails. Deployments and upgrades can be staged in advance during normal business hours so end users are not interrupted. After users are moved to the new application version (Green), the old version (Blue) can act as a failover if code must be rolled back to the previous version due to bugs or critical errors. Changes made on Blue never affect Green, including code running adapters and applications, database documents such as workflows, and configurations.

Blue-green architecture in Itential Platform

Itential structures its blue-green deployment architecture with two Itential Platform stacks defined as “Separate” and “Identical”.

Blue-green deployment architecture diagram showing separate and identical Itential Platform stacks with shared MongoDB and Redis — Itential Highly Available Architecture

Separate Itential Platform

Itential Platform that is “Separate” is defined as having a separate:

Logical database in MongoDB
Database in Redis

A “Separate” Itential Platform does not interfere with the “Identical” Itential Platform environment during the execution of automations.

Identical Itential Platform

Itential Platform is “Identical” to another Itential Platform if it has the same set of native resource models (defined below) in the MongoDB logical database. The database data required to make an “Identical” Itential Platform is:

An iap_profiles document for both Green Itential Platform and Blue Itential Platform
A service_configs document for both Green Itential Platform and Blue Itential Platform
An identical set of native resource model documents
An identical set of custom resource model documents owned by custom applications/adapters

Native resource models

Each Itential Platform in a blue-green deployment has a set of native resource models that configure Itential Platform to work with automations and resource components to provide a consistent development and automated management experience. These include the following collections, but may also include custom collections from custom applications/adapters.

Collections:

accounts
automations
catalog_store
component_groups
forms
groups
iap_profiles
iap_versioning
ids
integration_models
json_forms
mop_analytic_templates
mop_templates
rate_limit
roles
service_configs
tags
templates
transformations
triggers
ucm_compliance_reports
ucm_config_parsers
ucm_configs
ucm_golden_configs
ucm_json_specs
workflows

blue-green deployment process

Create a blue-green environment using the process outlined below. This requires Itential Platform release version 2023.1 and higher.

Create Green Itential Platform

Create a “Separate”, but “Identical” Itential Platform using the desired new version of Itential Platform. The new Itential Platform will be referred to as “Green” and the existing (old) Itential Platform will be referred to as “Blue”.

Green Itential Platform must have:

startJobs deactivated
Task Worker deactivated
An iap_profiles document
A service_configs document

Copy native resource models

Copy over all native resource models, including any running schema migrations.

Start Green Itential Platform

Start the Green Itential Platform.

Deactivate Blue startJobs

Deactivate startJobs on Blue Itential Platform.

Activate Green

Activate startJobs and Task Worker on Green Itential Platform.

Point traffic to Green

Point the Load Balancer or DNS at Green Itential Platform.

Deactivate Blue Task Worker

Once all jobs are completed on Blue Itential Platform, deactivate Task Worker.

Migrate execution data

Migrate any desired jobs and tasks and other automation execution data to Green Itential Platform for record keeping or another secure location for archived data.