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Overview

Polystack Orchestration is built on a three-tier architecture: an API tier that accepts template submissions, an engine tier that resolves dependencies and drives resource provisioning, and a plugin layer that delegates individual resource operations to the appropriate cloud service API. The engine is stateless — all stack state is persisted in a relational database, enabling horizontal engine scaling.
Administrator Access Required — This operation requires the admin role. Contact your Polystack administrator if you do not have sufficient permissions.

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Service Topology

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Service Components

The Orchestration API and CloudWatch-compatible API are separate processes. Both must be running for auto-scaling and WaitCondition resources to function correctly. Port 8000 must be accessible from instances that use WaitCondition signal URLs.

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How the Engine Processes a Template

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Request Flow Details

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Template Parsing

The engine parses the YAML template and evaluates all parameters sections, applying default values where the caller did not provide overrides. Intrinsic functions are not evaluated at parse time — they are resolved lazily when a resource is being provisioned and its dependencies are known.

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Dependency Graph Resolution

The engine constructs a directed acyclic graph (DAG) from:
  • Explicit depends_on declarations in resource definitions
  • Implicit dependencies detected from get_resource and get_attr references in resource properties
Resources without dependencies are provisioned in parallel. Resources with dependencies are queued until all prerequisite resources reach CREATE_COMPLETE.

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Resource Plugin Architecture

Each resource type (Polystack::Compute::Server, Polystack::Networking::Net, etc.) is handled by a dedicated plugin that implements a standard interface:

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Database Schema Overview

The Orchestration service persists all state in a dedicated database schema:

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Next Steps

Configuration

Configure the Orchestration service, quotas, and stack domain

Scaling the Service

Deploy multiple engine workers for high-throughput deployments

Security

Stack domain users, trust authorization, and policy configuration

Admin Troubleshooting

Diagnose engine failures and service-level issues