EmboFlow/design/08-decisions/adr-0002-executor-and-scheduler-separation.md

ADR-0002: Separate Executors From Schedulers

Status

Accepted

Context

EmboFlow needs to support multiple runtime modes now and later:

• direct Python execution
• Docker-isolated execution
• HTTP-based execution
• local scheduling
• future Kubernetes scheduling
• future Volcano scheduling

If execution logic and scheduling logic are coupled together, migration from single-host operation to cluster operation becomes costly.

Decision

The architecture will separate:

• Executor: how node logic runs
• Scheduler: where and under what dispatch policy tasks run

V1 executors:

• Python
• Docker
• HTTP

V1 scheduler:

• Local

Reserved future schedulers:

• Kubernetes
• Volcano

Consequences

Positive

• Cleaner evolution path
• Better runtime abstraction
• Less refactoring required for cluster migration

Negative

• Slightly more abstraction in V1 than the immediate deployment requires

Notes

User-injected code should default to Docker execution, while trusted platform logic may use Python execution.